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WO2003033530A2 - Antigenes mycobacteriens exprimes a haute tension en oxygene - Google Patents

Antigenes mycobacteriens exprimes a haute tension en oxygene Download PDF

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Publication number
WO2003033530A2
WO2003033530A2 PCT/GB2002/004647 GB0204647W WO03033530A2 WO 2003033530 A2 WO2003033530 A2 WO 2003033530A2 GB 0204647 W GB0204647 W GB 0204647W WO 03033530 A2 WO03033530 A2 WO 03033530A2
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WIPO (PCT)
Prior art keywords
dissolved oxygen
gene
oxygen tension
air saturation
mycobacterium
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PCT/GB2002/004647
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English (en)
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WO2003033530A3 (fr
Inventor
Brian James
Joanna Bacon
Philip March
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Health Protection Agency
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Priority to AU2002337287A priority Critical patent/AU2002337287A1/en
Publication of WO2003033530A2 publication Critical patent/WO2003033530A2/fr
Publication of WO2003033530A3 publication Critical patent/WO2003033530A3/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/195—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria
    • C07K14/35—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria from Mycobacteriaceae (F)
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K2039/505—Medicinal preparations containing antigens or antibodies comprising antibodies
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K2039/51—Medicinal preparations containing antigens or antibodies comprising whole cells, viruses or DNA/RNA
    • A61K2039/52—Bacterial cells; Fungal cells; Protozoal cells
    • A61K2039/522—Bacterial cells; Fungal cells; Protozoal cells avirulent or attenuated
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K2039/51—Medicinal preparations containing antigens or antibodies comprising whole cells, viruses or DNA/RNA
    • A61K2039/53—DNA (RNA) vaccination
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies

Definitions

  • the present invention relates to a method of identifying a gene in mycobacteria the expression of which gene is induced or up-regulated during continuous culture of mycobacteria under growth conditions defined by a high dissolved oxygen tension, to the isolated peptide products or variants or derivatives or fragments thereof and to inhibitors thereof, to antibodies that bind to said peptides, variants, derivatives or fragments, to DNA and RNA vectors that express said peptides, variants, derivatives or fragments, to attenuated mycobacteria in which the activity of at least one of said induced or up-regulated genes has been modified, to vaccines against mycobacterial infections, and to methods of detecting a mycobacterial infection.
  • microorganisms are capable of forming intracellular infections. These include: infections caused by species of Salmonella, Yersinia, Shigella, Campylobacter, Chlamydia and Mycobacteria. Some of these infections are exclusively intracellular, others contain both intracellular and extracellular components. However, it is the intracellular survival cycle of bacterial infection which is suspected as a main supportive factor for disease progression.
  • these microorganisms do not circulate freely in the body, for example, in the bloodstream, and are often not amenable to drug treatment regimes. Where drugs are available, this problem has been exacerbated by the development of multiple drug resistant microorganisms.
  • vaccine therapies have not proved effective against such intracellular microorganisms. Also, increased systemic concentration of antibiotics to improve bioavailability within cells may result in severe side effects.
  • Mycobacterium tuberculosis and closely related species make up a small group of mycobacteria known as the Mycobacterium tuberculosis complex (MTC).
  • MTC Mycobacterium tuberculosis complex
  • This group comprises four species M. tuberculosis, M. microti, M. bovis and M. africanum which are the causative agent in the majority of tuberculosis (TB) cases throughout the world.
  • M. tuberculosis is responsible for more than three million deaths a year world-wide.
  • Other mycobacteria are also pathogenic in man and animals, for example M. avium subsp. paratuberculosiswhlch causes Johne's disease in ruminants, M. bovis which causes tuberculosis in cattle, M. avium and M. intracellulare which cause tuberculosis in immunocompromised patients (eg. AIDS patients, and bone marrow transplant patients) and M. leprae which causes leprosy in humans.
  • M. vaccae Another important mycobacterial species is M. vaccae.
  • M. tuberculosis infects macrophage cells within the body. Soon after macrophage infection, most M. tuberculosis bacteria enter, persist and replicate within cellular phagosome vesicles, where the bacteria are sequestered from host defences and extracellular factors.
  • a further problem is that of providing an adequate bioavailability of the drug within the cells to be treated. Whilst it is possible to increase the systemic concentration of a drug (eg. by administering a higher dosage) this may result in severe side effects caused by the increased drug concentration.
  • the effectiveness of vaccine prevention against M. tuberculosis has varied widely.
  • the current M. tuberculosis vaccine, BCG is an attenuated strain of M. bovis. It is effective against severe complications of TB in children, but it varies greatly in its effectiveness in adults particularly across ethnic groups.
  • BCG vaccination has been used to prevent tuberculous meningitis and helps prevent the spread of M. tuberculosis to extra-pulmonary sites, but does not prevent infection.
  • the limited efficacy of BCG and the global prevalence of TB has led to an international effort to generate new, more effective vaccines.
  • the current paradigm is that protection will be mediated by the stimulation of a Th1 immune response.
  • BCG vaccination in man was given orally when originally introduced, but that route was discontinued because of loss of viable BCG during gastric passage and of frequent cervical adenopathy.
  • aerosol or intra- tracheal delivery of BCG has been achieved without adverse effects, but has varied in efficacy from superior protection than parenteral inoculation in primates, mice and guinea pigs to no apparent advantage over the subcutaneous route in other studies.
  • mycobacterial growth follows a typical sigmoid growth curve involving an exponential growth phase and a stationary phase.
  • the transition from exponential phase to stationary phase involves rapid and transient switches in terms of gene and protein expression, which switches are initiated by a complex set of undefined or poorly defined interactive stimuli as the mycobacteria become starved of essential nutrients.
  • an isolated mycobacterial peptide or a fragment or derivative or variant thereof wherein the peptide is encoded by a gene the expression of which is induced or up-regulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C.
  • the continuous culture methods employed by the present invention are particularly advantageous when compared with the crude, prior art batch culture methods. This is because continuous culture permits strict control of growth culture parameters such as pH, available nutrients, constant growth rate, and dissolved oxygen tension.
  • the prior art batch culture systems are either poorly controlled or totally uncontrolled systems and therefore involve a variety of interactive stimuli as the mycobacteria become starved of essential nutrients.
  • the mycobacteria are exposed to a complex range of starvation stimuli, which stimuli may obscure or modify the cellular effects associated with a single rapid or transient stimulus in isolation.
  • the present invention is concerned with the principal stimulus of a high dissolved oxygen tension, optionally with the co-stimulus of iron limitation.
  • the principal induction parameter is that of a high dissolved oxygen tension (ie. at least 30% air saturation when measured at 37°C).
  • the accidental induction or upregulation of genes that are solely responsive to environmental switches other than to a high dissolved oxygen tension may be substantially prevented. Accordingly, false-positive identification of genes whose induction or up-regulation is unrelated to a high dissolved oxygen tension may be substantially avoided.
  • the dissolved oxygen tension threshold defining the low oxygen culture condition is up to 7 % air saturation when measured at 37 °C, more preferably up to 5 % air saturation when measured at 37 °C, and particularly preferably up to 3 % air saturation at 37 °C.
  • the DOT threshold defining low oxygen culture conditions is up to 1 % air saturation when measured at 37 °C.
  • the minimum dissolved oxygen tension defining the high oxygen culture condition is 40 % air saturation when measured at 37 °C, more preferably 45 % air saturation when measured at 37 °C, and most preferably 50 % air saturation when measured at 37 °C.
  • the pH of the culture medium is preferably maintained between pH 6 and 8, more preferably between pH 6.5 and 7.5, most preferably at about pH 6.9.
  • the dissolved oxygen tension (DOT) parameter is calculated by means of an oxygen electrode and conventional laboratory techniques.
  • 100 % air saturation corresponds to a solution that is saturated with air
  • 0 % corresponds to a solution that has been thoroughly purged with an inert gas such as nitrogen.
  • Calibration is performed under standard atmospheric pressure conditions at 37 °C, and with conventional air comprising approximately 21 % oxygen.
  • a reference temperature and pressure is indicated for DOT measurements as DOT may vary with temperature and pressure.
  • the high oxygen tension induction conditions of the present invention are culture conditions that the present inventors believe would be conducive for a mycobacterium to express at least one gene that would be normally expressed in vivo during infection, or during/following re-activation of a mycobacterium from a latent state. Latency is discussed in more detail below.
  • mycobacteria eg. M. tuberculosis
  • mycobacteria encounter a dynamic host environment and modulate the expression of genes required for infection.
  • tubercle bacilli reside in a number of different locations in the lung, for example lining the walls of cavitary lesions where the close proximity to bronchioles provides a source of air; within macrophages where oxygen availability may be more limited or within granulomas.
  • mycobacteria such as M. tuberculosis must be able to adapt and respond to changes in oxygen availability in order to cause infection.
  • the initial stages of infection which include dissemination and phagocytosis, occur under aerobic conditions, during which the tubercle bacilli replicate rapidly.
  • mycobacteria such as M. tuberculosis can adapt and survive under oxygen-depleted conditions, and can grow over a range of oxygen tensions. Adaptation to a low dissolved oxygen tension triggers transition to a non-replicating persistent state in vitro that may be analogous to latency in vivo.
  • latency is synonymous with persistence, and describes a reversible state of low metabolic activity in which mycobacterial cells can survive for extended periods without cell division. During latency, the clinical symptoms associated with a mycobacterial infection do not become manifest, and the host suffers no significant ill.
  • re-activation of latent mycobacteria may occur when oxygen and nutrients, previously limiting, become available. This may happen, for example, following breakdown of a mycobacterial infected granuloma structure.
  • Antigens expressed under aerobic conditions may play an early and important role in the development of an effective immune response and consequently represent potential vaccine candidates.
  • genes expressed under aerobic conditions are important therapeutic targets for preventing the establishment, spread and reactivation of disease.
  • Such antigens and genes may form the basis for vaccines against pre- and post-infections by mycobacteria.
  • the present inventors also believe that iron limitation (as a co-stimulus with a high DOT) plays an important role in the mycobacterial activation and re-activation cycle.
  • the present invention is also concerned with genes and peptides that are expressed during in vitro co-stimulation with iron limitation and a high DOT, and the various aspects of the present invention therefore include, as a preferred feature, the co-stimulus of iron limitation.
  • a mycobacterial culture is considered to be iron-limited when the medium concentration of iron (ie. Fe 2+ ) is 0.2 mg/per litre or less, preferably 0.1 mg per litre or less, and most preferably 0.08 mg per litre or less.
  • a mycobacterial culture is considered to be not iron-limited (ie. iron-replete) when the medium concentration of iron (ie. Fe 2+ ) is greater than 0.1 mg per litre, preferably greater than 0.2 mg per litre, more preferably greater than 0.3 mg per litre.
  • those genes that are up-regulated by at least 1.5-fold under high oxygen culture conditions (and optionally iron-limited conditions) vis-avis low oxygen culture conditions are selected.
  • the corresponding up-regulation selection criterion is at least 2-fold, more preferably 3- fold, most preferably 4-fold.
  • up-regulation levels of at least 10-fold, preferably 50-fold may be employed.
  • the gene and peptide (plus related) applications of the present invention preferably concern not only genes and peptides that are up-regulated under high DOT conditions by the above-defined levels, but also genes and peptides that are up-regulated under high DOT and iron limitation by the above-defined levels.
  • the mycobacterium is selected from the species M. phlei, M. smegmatis, M. africanum, M. caneti, M. fortuitum, M. marinum, M. ulcerans, M. tuberculosis, M. bovis, M. microti, M. avium, M. paratuberculosis, M. leprae, M. lepraemurium, M. intracellulare, M. scrofulaceum, M. xenopi, M. genavense, M. kansasii, M. simiae, M. szulgai, M. haemophilum, M. asiaticum, M. malmoense, M. vaccae and M. shimoidei. Of particular interest are members of the MTC, preferably M. tuberculosis.
  • Suitable media for culturing mycobacteria are described in Wayne, L.G. (1994) [in Tuberculosis: Pathogenesis, Protection, and Control published by the American Society for Microbiology, pp. 73-83]. These include Middlebrook 7H9 Medium [see Barker, L.P., et al. (1998) Molec. Microbiol., vol. 29(5), pp. 1167-1177, and WO00/52139 in the name of the present Applicant].
  • a peptide is substantially pure when at least about 60 to 75% of a sample exhibits a single peptide sequence.
  • a substantially pure peptide will typically comprise about 60 to 90% w/w of a protein sample, more usually about 95%, and preferably will be over about 99% pure.
  • Peptide purity or homogeneity may be indicated by, for example, polyacrylamide gel electrophoresis of a protein sample, followed by visualizing a single polypeptide band upon staining the gel. Alternatively, higher resolution may be provided by using, for example, HPLC.
  • a peptide is considered to be isolated when it is separated from the contaminants which accompany it in its natural state.
  • a peptide which is chemically synthesized or synthesized in a cellular system different from the cell from which it naturally originates will be substantially free from its naturally associated components.
  • the present invention provides peptides which may be purified from mycobacteria as well as from other types of cells transformed with recombinant nucleic acids encoding these peptides.
  • amino acid sequence of the proteins of the present invention may be determined by protein sequencing methods.
  • peptide oligopeptide
  • polypeptide protein
  • post-translational modifications such as glycosylation, acetylation, and phosphorylation.
  • fragment means a peptide having at least five, preferably at least ten, more preferably at least twenty, and most preferably at least thirty-five amino acid residues of the peptide which is the gene product of the induced or up-regulated gene in question.
  • the fragment preferably includes at least one epitope of the gene product in question.
  • variant means a peptide or peptide fragment having at least seventy, preferably at least eighty, more preferably at least ninety percent amino acid sequence homology with the peptide which is the gene product of the induced or up-regulated gene in question.
  • An example of a “variant” is a peptide or peptide fragment of an induced/up-regulated gene which contains one or more analogs of an amino acid (eg. an unnatural amino acid), or a substituted linkage.
  • the terms “homology” and “identity” are considered synonymous in this specification.
  • a “variant” may be a mimic of the peptide or peptide fragment, which mimic reproduces at least one epitope of the peptide or peptide fragment.
  • the mimic may be, for example, a nucleic acid mimic, preferably a DNA mimic.
  • sequence comparison typically one sequence acts as a reference sequence, to which test sequences may be compared.
  • test and reference sequences are input into a computer, subsequent coordinates are designated, if necessary, and sequence algorithm program parameters are designated.
  • sequence comparison algorithm then calculates the percentage sequence identity for the test sequence(s) relative to the reference sequence, based on the designated program parameters.
  • Optimal alignment of sequences for comparison may be conducted, for example, by the local homology alignment algorithm of Smith and Waterman [Adv. Appl. Math. 2: 484 (1981 )], by the algorithm of Needleman & Wunsch [J. Mol. Biol. 48: 443 (1970)] by the search for similarity method of Pearson & Lipman [Proc. Nat'l. Acad. Sci. USA 85: 2444 (1988)], by computer implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA - Sequence Analysis Software Package of the Genetics Computer Group, University of Wisconsin Biotechnology Center, 1710 University Avenue, Madison, Wis. 53705), or by visual inspection [see Current Protocols in Molecular Biology, F.M. Ausbel et al, eds, Current Protocols, a joint venture between Greene Publishing Associates, In. And John Wiley & Sons, Inc. (1995 Supplement) Ausbubel].
  • the identity exists over a region of the sequences that is at least 10 amino acids, preferably at least 20 amino acids, more preferably at least 35 amino acids in length.
  • derivative means a protein comprising the peptide (or fragment, or variant thereof) which peptide is the gene product of the induced or up-regulated gene in question.
  • a derivative may include the peptide in question, and a further peptide sequence which may introduce one or more additional epitopes.
  • the further peptide sequence should preferably not interfere with the basic folding and thus conformational structure of the peptide in question.
  • Examples of a “derivative” are a fusion protein, a conjugate, and a graft.
  • two or more peptides (or fragments, or variants) may be joined together to form a derivative.
  • a peptide (or fragment, or variant) may be joined to an unrelated molecule (eg.
  • Derivatives may be chemically synthesized, but will be typically prepared by recombinant nucleic acid methods. Additional components such as lipid, and/or polysaccharide, and/or polyketide components may be included.
  • fragments all of the molecules "fragment”, “variant” and “derivative” have a common antigenic cross-reactivity and/or substantially the same in vivo biological activity as the gene product of the induced or up-regulated gene in question from which they are derived.
  • an antibody capable of binding to a fragment, variant or derivative would be also capable of binding to the gene product of the induced or up-regulated gene in question.
  • the fragment, variant and derivative each possess the active site of the peptide which is the induced or up-regulated peptide in question.
  • all of the above embodiments of a peptide of the present invention share a common ability to induce a "recall response" of a T-lymphocyte which has been previously exposed to an antigenic component of a mycobacterial infection.
  • the peptide is selected from the group consisting of SEQ ID NO: 1 , 3, 5, 7, 9, 11 , 13, 15, 17, 19, 21 , 23, 25, 27, 29, 31 , 33, 35, 37, 39, 41 , 43, 45, 47, 49, 51 , 53, 55, 57, 59, 61 , 63, 65, 67, 69, 71 , 73, 75, 77, 79, 81 , 83, 85, 87, 89, 91 , 93, 95, 97, 99, 101 , 103, 105, 107, 109, 111 , 113, 115, 117, 119, 121 , 123, 125, 127, 129, 131 , 133, 135, 137, 139, 141 , 143, 145, 147, 149, 151 , 153, 155, 157, 159, 161 , 163, 165, 167, 169, 171 , 173, 175,
  • a method of identifying a mycobacterial gene the expression of which is induced or upregulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C said method comprising:- culturing a first mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C; culturing a second mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of up to 10 % air saturation measured at 37
  • first and second mRNA populations from said first and second mycobacteria, respectively; preparing first and second cDNA populations from said first and second mRNA populations, respectively, during which cDNA preparation a detectable label is introduced into the cDNA molecules of the first and second cDNA populations; isolating corresponding first and second cDNA molecules from the first and second cDNA populations, respectively; comparing relative amounts of label or corresponding signal emitted from the label present in the isolated first and second cDNA molecules; identifying a greater amount of label or signal provided by the isolated first cDNA molecule than that provided by the isolated second cDNA molecule; and identifying the first cDNA and the corresponding mycobacterial gene which is induced or up-regulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C.
  • Corresponding first and second cDNA molecules from the first and second cDNA populations refers to cDNAs having substantially the same nucleotide sequence.
  • each culture condition ie. high oxygen, and low oxygen
  • the cDNA copy number reflects the corresponding mRNA copy number for each culture condition, and thus it is possible to identify induced or up-regulated genes.
  • the first and second cDNA molecules are isolated from the corresponding cDNA populations by hybridisation to an array containing immobilised DNA sequences that are representative of each known gene (or ORF) within a particular mycobacterial species' genome.
  • a first cDNA may be considered "corresponding" to a second cDNA if both cDNAs hybridise to the same immobilised DNA sequence.
  • representative DNA sequences from a particular mycobacterial strain, or from a number of different species and/or strains may be employed in the array.
  • first and second cDNAs are prepared by incorporation of a fluorescent label.
  • the first and second cDNAs may incorporate labels which fluoresce at different wavelengths, thereby permitting dual fluorescence and simultaneous detection of two cDNA samples.
  • a confocal laser scanner is preferably employed.
  • fluorescently labelled cDNA sequences from low and high oxygen cultured systems were allowed to hybridise with a whole mycobacterial genome array.
  • the first cDNA population was labelled with fluorescent label A
  • the second cDNA population was labelled with fluorescent label B.
  • the array was scanned at two different wavelengths corresponding to the excitable maxima of each dye and the intensity of the emitted light was recorded. Multiple arrays were prepared for each cDNA and a mean intensity value was calculated across the two cDNA populations for each spot with each dye, against which relative induction or up-regulation was quantified.
  • genomic DNA may be isolated from the first and second mycobacteria.
  • labelled DNA is also prepared from isolated DNA. The labelled DNA may be then included on each array as a control.
  • an inhibitor of a mycobacterial peptide wherein the peptide is encoded by a gene the expression of which is induced or up-regulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C, and wherein the inhibitor is capable of preventing or inhibiting the mycobacterial peptide from exerting its native biological effect.
  • Inhibition of the mycobacterial peptide may be effected at the nucleic acid level (ie. DNA, or RNA), or at the peptide level.
  • the inhibitor is capable of inhibiting one or more of acyl carrier protein, maturase, alcohol dehydrogenase, ATP-binding protein, fatty acid CoA ligase, fatty acid CoA synthetase, fatty acid CoA synthase, cobinamide kinase, cobinamide phosphate guanyl transferase, carbon monoxyde dehydrogenase, oxidoreductase, galactokinase, exonuclease, exodeoxyribonuclease, alpha mannosidase, D-3-phosphoglycerate dehydrogenase, protease, thioredoxin, dehydrogenase, monooxygenase, 5'-phosphoribosylglycinamide formyl transferase, transformylase, riboflavin synthase, acyl transferase, threanine dehydratase, molybdopterin
  • the inhibitor may be an antibiotic capable of targeting the induced or up-regulated mycobacterial gene identifiable by the present invention, or the gene product thereof.
  • the antibiotic is preferably specific for the gene and/or gene product.
  • Inhibitors of the present invention may be prepared utilizing the sequence information provided herein. For example, this may be performed by overexpressing the peptide, purifying the peptide, and then performing X-ray crystallography on the purified peptide to obtain its molecular structure. Next, compounds are created which have similar molecular structures to all or portions of the peptide or its substrate. The compounds may be then combined with the peptide and attached thereto so as to block one or more of its biological activities. Also included within the invention are isolated or recombinant polynucleotides that bind to the regions of the mycobacterial chromosome containing sequences that are associated with induction/up-regulation under high oxygen tension, including antisense and triplex-forming polynucleotides.
  • binding refers to an interaction or complexation between an oligonucleotide and a target nucleotide sequence, mediated through hydrogen bonding or other molecular forces.
  • binding more specifically refers to two types of internucleotide binding mediated through base-base hydrogen bonding.
  • the first type of binding is "Watson-Crick-type” binding interactions in which adenine-thymine (or adenine-uracil) and guanine-cytosine base-pairs are formed through hydrogen bonding between the bases.
  • An example of this type of binding is the binding traditionally associated with the DNA double helix and in RNA-DNA hybrids; this type of binding is normally detected by hybridization procedures.
  • triplex binding refers to any type of base-base hydrogen bonding of a third polynucleotide strand with a duplex DNA (or DNA-RNA hybrid) that is already paired in a Watson-Crick manner.
  • the inhibitor may be an antisense nucleic acid sequence which is complementary to at least part of the inducible or up-regulatable gene.
  • the inhibitor when in the form of a nucleic acid sequence, in use, comprises at least 15 nucleotides, preferably at least 20 nucleotides, more preferably at least 30 nucleotides, and most preferably at least 50 nucleotides.
  • an antibody that binds to a peptide encoded by a gene, or to a fragment or variant or derivative of said peptide, the expression of which gene is induced or up-regulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 C C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C.
  • the antibody preferably has specificity for the peptide in question, and following binding thereto may initiate coating of a mycobacterium expressing said peptide.
  • Coating of the bacterium preferably leads to opsonization thereof. This, in turn, leads to the bacterium being destroyed. It is preferred that the antibody is specific for the mycobacterium (eg. species and/or strain) which is to be targeted.
  • Opsonization by antibodies may influence cellular entry and spread of mycobacteria in phagocytic and non-phagocytic cells by preventing or modulating receptor- mediated entry and replication in macrophages.
  • the peptides, fragments, variants or derivatives of the present invention may be used to produce antibodies, including polyclonal and monoclonal. If polyclonal antibodies are desired, a selected mammal (eg. mouse, rabbit, goat, horse, etc.) is immunized with an immunogenic polypeptide. Serum from the immunized animal is collected and treated according to known procedures. If serum containing polyclonal antibodies to a desired mycobacterial epitope contains antibodies to other antigens, the polyclonal antibodies may be purified by immunoaffinity chromatography.
  • monoclonal antibodies by hybridomas involving, for example, preparation of immortal antibody-producing cell lines by cell fusion, or other techniques such as direct transformation of B lymphocytes with oncogenic DNA, or transfection with Epstein-Barr virus may be employed.
  • the antibody employed in this aspect of the invention may belong to any antibody isotype family, or may be a derivative or mimic thereof.
  • Reference to antibody throughout this specification embraces recombinantly produced antibody, and any part of an antibody which is capable of binding to a mycobacterial antigen.
  • the antibody belongs to the IgG, IgM or IgA isotype families.
  • the antibody belongs to the IgA isotype family.
  • Reference to the IgA isotype throughout this specification includes the secretory form of this antibody (ie. slgA).
  • the secretory component (SC) of slgA may be added in vitro or in vivo. In the latter case, the use of a patient's natural SC labelling machinery may be employed.
  • the antibody may be raised against a peptide from a member of the MTC, preferably against M. tuberculosis.
  • the antibody is capable of binding to a peptide selected from the group consisting of SEQ ID NO: 1 , 3, 5, 7, 9, 11 , 13, 15, 17, 19, 21 , 23, 25, 27, 29, 31 , 33, 35, 37, 39, 41 , 43, 45, 47, 49, 51 , 53, 55, 57, 59, 61 , 63, 65, 67, 69, 71 , 73, 75, 77, 79, 81 , 83, 85, 87, 89, 91 , 93, 95, 97, 99, 101 , 103, 105, 107, 109, 111 , 113, 115, 117, 119, 121 , 123, 125, 127, 129, 131 , 133, 135, 137, 139, 141 , 143, 145, 147, 149, 151 , 153, 155, 157, 159, 161 , 163, 165, 167, 169, 17
  • the antigen is an exposed component of a mycobacterial bacillus. In another embodiment, the antigen is a cell surface component of a mycobacterial bacillus.
  • the antibody of the present invention may be polyclonal, but is preferably monoclonal.
  • the passive protection aspect (ie. delivery of antibodies) of the present invention is facilitated by enhanced accessibility of the antibodies of the present invention to antigens on mycobacterial bacilli. It is possible that antibody binding may block macrophage infection by steric hindrance or disruption of its oligomeric structure. Thus, antibodies acting on mycobacterial bacilli released from O killed, infected macrophages may interfere with the spread of re-infection to fresh macrophages. This hypothesis involves a synergistic action between antibodies and cytotoxic T cells, acting early after infection, eg. y ⁇ and NK T cells, but could later involve also CD8 and CD4 cytotoxic T cells.
  • an attenuated mycobacterium in which a gene has been modified thereby rendering the mycobacterium substantially non-pathogenic, wherein said gene is a gene the expression of which is induced or up-regulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C.
  • modified refers to any genetic manipulation such as a nucleic acid or nucleic acid sequence replacement, a deletion, or an insertion which renders the mycobacterium substantially non-pathogenic.
  • the entire inducible or up-regulatable gene may be deleted.
  • the gene to be modified has a wild-type coding sequence corresponding to one of the group consisting of SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114,116, 118, 120, 122, 124, 126, 128, 130, 132, 134,136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188,
  • wild-type sequences may include minor variations depending on the Database employed.
  • an attenuated microbial carrier comprising a peptide encoded by a gene, or a fragment or variant or derivative of said peptide, the expression of which gene is induced or upregulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C.
  • the peptide (or fragment, variant or derivative) is either at least partially exposed at the surface of the carrier, or the carrier becomes degraded in vivo so that at least part of the peptide (or fragment, variant or derivative) is otherwise exposed to a host's immune system.
  • the attenuated microbial carrier is selected from the group consisting of attenuated salmonella, attenuated vaccinia virus, attenuated fowlpox virus, or attenuated M. bovis (eg. BCG strain).
  • the peptide is selected from the group consisting of SEQ ID NO: 1 , 3, 5, 7, 9, 11 , 13, 15, 17, 19, 21 , 23, 25, 27, 29, 31 , 33, 35, 37, 39, 41 , 43, 45, 47, 49, 51 , 53, 55, 57, 59, 61 , 63, 65, 67, 69, 71 , 73, 75, 77, 79, 81 , 83, 85, 87, 89, 91 , 93, 95, 97, 99, 101 , 103, 105, 107, 109, 111 , 113, 115, 117, 119, 121 , 123, 125, 127, 129, 131 , 133, 135, 137, 139, 141 , 143, 145, 147, 149, 151 , 153, 155, 157, 159, 161 , 163, 165, 167, 169, 171 , 173, 175,
  • a DNA plasmid comprising a promoter, a polyadenylation signal, and a DNA sequence that encodes a gene or a fragment or variant or derivative of said gene, the expression of which gene is induced or up-regulated during culture of a mycobacterium under continuous culture conditions defined by a dissolved oxygen tension of at least 30 % air saturation measured at 37 °C when compared with a dissolved oxygen tension of up to 10 % air saturation measured at 37 °C, wherein the promoter and polyadenylation signal are operably linked to the DNA sequence.
  • plasmid is considered equivalent to vector and thus need not necessarily be a closed (ie. circular) piece of DNA.
  • DNA "fragment" used in this invention will usually comprise at least about 5 codons (15 nucleotides), more usually at least about 7 to 15 codons, and most preferably at least about 35 codons. This number of nucleotides is usually about the minimal length required for a successful probe that would hybridize specifically with such a sequence.
  • the DNA "fragment” has a nucleotide length which is at least 50%, preferably at least 70%, and more preferably at least 80% that of the coding sequence of the corresponding induced/up-regulated gene.
  • DNA “variant” means a DNA sequence which has substantial homology or substantial similarity to the coding sequence (or a fragment thereof) of an induced/up-regulated gene.
  • a nucleic acid or fragment thereof is “substantially homologous” (or “substantially similar”) to another if, when optimally aligned (with appropriate nucleotide insertions or deletions) with the other nucleic acid (or its complementary strand), there is nucleotide sequence identity in at least about 60% of the nucleotide bases, usually at least about 70%, more usually at least about 80%, preferably at least about 90%, and more preferably at least about 95 to 98% of the nucleotide bases. Homology determination is performed as described supra for peptides.
  • a DNA "variant” is substantially homologous (or substantially similar) with the coding sequence (or a fragment thereof) of an induced/up-regulated gene when they are capable of hybridizing under selective hybridization conditions.
  • Selectivity of hybridization exists when hybridization occurs which is substantially more selective than total lack of specificity.
  • selective hybridization will occur when there is at least about 65% homology over a stretch of at least about 14 nucleotides, preferably at least about 70%, more preferably at least about 75%, and most preferably at least about 90%. See, Kanehisa (1984) Nuc. Acids Res. 12:203-213.
  • the length of homology comparison, as described, may be over longer stretches, and in certain embodiments will often be over a stretch of at least about 17 nucleotides, usually at least about 20 nucleotides, more usually at least about 24 nucleotides, typically at least about 28 nucleotides, more typically at least about 32 nucleotides, and preferably at least about 36 or more nucleotides.
  • Nucleic acid hybridization will be affected by such conditions as salt concentration (eg. NaCl), temperature, or organic solvents, in addition to the base composition, length of the complementary strands, and the number of nucleotide base mismatches between the hybridizing nucleic acids, as will be readily appreciated by those skilled in the art.
  • Salt concentration eg. NaCl
  • Temperatur e.g., a temperature, or organic solvents
  • Stringent temperature conditions are preferably employed, and generally include temperatures in excess of 30°C, typically in excess of 37°C and preferably in excess of 45°C.
  • Stringent salt conditions will ordinarily be less than 1000 mM, typically less than 500 mM, and preferably less than 200 mM.
  • the pH is typically between 7.0 and 8.3. However, the combination of parameters is much more important than the measure of any single parameter. See, eg., Wetmur and Davidson (1968) J. Mol. Biol. 31 :349-370.
  • DNA “derivative” means a DNA polynucleotide which comprises a DNA sequence (or a fragment, or variant thereof) corresponding to the coding sequence of the induced/up-regulated gene and an additional DNA sequence which is not naturally associated with the DNA sequence corresponding to the coding sequence.
  • a “derivative” may, for example, include two or more coding sequences of a mycobacterial operon, which operon is induced during high DOT conditions.
  • the expression product/s of such a "derivative” may be a fusion protein or separate peptide products encoded by the individual coding regions.
  • DNA “fragment”, “variant”, and “derivative” have in common with each other that the resulting peptide products have cross-reactive antigenic properties which are substantially the same as those of the corresponding wild-type peptide.
  • all of the peptide products of the above DNA molecule embodiments of the present invention bind to an antibody which also binds to the wild-type peptide.
  • all of the above peptide products are capable of inducing a "recall response" of a T lymphocyte which has been previously exposed to an antigenic component of a mycobacterial infection.
  • the promoter and polyadenylation signal are preferably selected so as to ensure that the gene is expressed in a eukaryotic cell. Strong promoters and polyadenylation signals are preferred.
  • the present invention provides an isolated RNA molecule that is encoded by a DNA sequence of the present invention, or a fragment or variant or derivative of said DNA sequence.
  • RNA is an RNA which is substantially separated from other mycobacterial components that naturally accompany the sequences of interest, eg. ribosomes, polymerases, and other mycobacterial polynucleotides such as DNA and other chromosomal sequences.
  • RNA molecule may be introduced directly into a host cell as, for example, a component of a vaccine.
  • RNA molecule may be incorporated into an RNA vector prior to administration.
  • the polynucleotide sequences (DNA and RNA) of the present invention include a nucleic acid sequence that has been removed from its naturally occurring environment, and recombinant or cloned DNA isolates and chemically synthesized analogues or analogues biologically synthesized by heterologous systems.
  • the term "recombinant" as used herein intends a polynucleotide of genomic, cDNA, semisynthetic, or synthetic origin which, by virtue of its origin or manipulation: (1 ) is not associated with all or a portion of a polynucleotide with which it is associated in nature; or (2) is linked to a polynucleotide other than that to which it is linked in nature; and (3) does not occur in nature.
  • This artificial combination is often accomplished by either chemical synthesis means, or by the artificial manipulation of isolated segments of nucleic acids, eg. , by genetic engineering techniques. Such is usually done to replace a codon with a redundant codon encoding the same or a conservative amino acid, while typically introducing or removing a sequence recognition site. Alternatively, it is performed to join together nucleic acid segments of desired functions to generate a desired combination of functions.
  • the polynucleotides may encode a peptide that is induced or up-regulated under high oxygen tension.
  • a nucleic acid is said to "encode" a peptide if, in its native state or when manipulated, it can be transcribed and/or translated to produce the peptide or a fragment or variant or derivative thereof.
  • the anti-sense strand of such a nucleic acid is also said to encode the sequence.
  • Expression vectors comprising the polynucleotide of interest.
  • Expression vectors generally are replicable polynucleotide constructs that encode a peptide operably linked to suitable transcriptional and translational regulatory elements.
  • regulatory elements usually included in expression vectors are promoters, enhancers, ribosomal binding sites, and transcription and translation initiation and termination sequences. These regulatory elements are operably linked to the sequence to be translated.
  • a nucleic acid sequence is operably linked when it is placed into a functional relationship with another nucleic acid sequence. For instance, a promoter is operably linked to a coding sequence if the promoter affects its transcription or expression.
  • operably linked means that the DNA sequences being linked are contiguous and, where necessary to join two protein coding regions, contiguous and in reading frame.
  • the regulatory elements employed in the expression vectors containing a polynucleotide encoding a virulence factor are functional in the host cell used for expression.
  • the polynucleotides of the present invention may be prepared by any means known in the art. For example, large amounts of the polynucleotides may be produced by replication in a suitable host cell.
  • the natural or synthetic DNA fragments coding for a desired fragment will be incorporated into recombinant nucleic acid constructs, typically DNA constructs, capable of introduction into and replication in a prokaryotic or eukaryotic cell.
  • DNA constructs will be suitable for autonomous replication in a unicellular host, such as yeast or bacteria, but may also be intended for introduction to and integration within the genome of a cultured insect, mammalian, plant or other eukaryotic cell lines.
  • the polynucleotides of the present invention may also be produced by chemical synthesis, eg. by the phosphoramidite method or the triester method, and may be performed on commercial automated oligonucleotide synthesizers.
  • a double-stranded fragment may be obtained from the single stranded product of chemical synthesis either by synthesizing the complementary strand and annealing the strand together under appropriate conditions or by adding the complementary strand using DNA polymerase with an appropriate primer sequence.
  • DNA constructs prepared for introduction into a prokaryotic or eukaryotic host will typically comprise a replication system recognized by the host, including the intended DNA fragment encoding the desired peptide, and will preferably also include transcription and translational initiation regulatory sequences operably linked to the polypeptide encoding segment.
  • Expression vectors may include, for example, an origin of replication or autonomously replicating sequence (ARS) and expression control sequences, a promoter, an enhancer and necessary processing information sites, such as ribosome-binding sites, RNA splice sites, polyadenylation sites, transcriptional terminator sequences, and mRNA stabilizing sequences.
  • ARS origin of replication or autonomously replicating sequence
  • Secretion signals from polypeptides secreted from the host cell of choice may also be included where appropriate, thus allowing the protein to cross and/or lodge in cell membranes, and thus attain its functional topology or be secreted from the cell.
  • promoter and other necessary vector sequences are selected so as to be functional in the host, and may, when appropriate, include those naturally associated with mycobacterial genes. Promoters such as the trp, lac and phage promoters, tRNA promoters and glycolytic enzyme promoters may be used in prokaryotic hosts. Useful yeast promoters include the promoter regions for metallothionein, 3-phosphoglycerate kinase or other glycolytic enzymes such as enolase orglyceraldehyde-3-phosphate dehydrogenase, enzymes responsible for maltose and galactose utilization, and others.
  • Non-native mammalian promoters may include the early and late promoters from SV40 or promoters derived from murine moloney leukemia virus, mouse mammary tumour virus, avian sarcoma viruses, adenovirus II, bovine papilloma virus or polyoma.
  • the construct may be joined to an amplifiable gene (eg. DHFR) so that multiple copies of the gene may be made.
  • While such expression vectors may replicate autonomously, they may less preferably replicate by being inserted into the genome of the host cell.
  • Expression and cloning vectors may contain a selectable marker, a gene encoding a protein necessary for the survival or growth of a host cell transformed with the vector. The presence of this gene ensures the growth of only those host cells which express the inserts.
  • Typical selection genes encode proteins that (a) confer resistance to antibiotics or other toxic substances, e.g. ampicillin, neomycin, methotrexate, etc.; (b) complement auxotrophic deficiencies; or (c) supply critical nutrients not available from complex media, e.g. the gene encoding D-alanine racemase for Bacilli. The choice of appropriate selectable marker will depend on the host cell.
  • the vectors containing the nucleic acids of interest can be transcribed in vitro and the resulting RNA introduced into the host cell (eg. by injection), or the vectors can be introduced directly into host cells by methods which vary depending on the type of cellular host, including electroporation; transfection employing calcium chloride, rubidium chloride, calcium phosphate, DEAE-dextran, or other substances; microprojectile bombardment; lipofection; infection (where the vector is an infectious agent, such as a retroviral genome).
  • the cells into which have been introduced nucleic acids described above are meant to also include the progeny of such cells.
  • nucleic acids and peptides of the present invention may be prepared by expressing the nucleic acids or portions thereof in vectors or other expression vehicles in compatible prokaryotic or eukaryotic host cells.
  • prokaryotic hosts are strains of Esche chia coli, although other prokaryotes, such as Bacillus subtilis or Pseudomonas may also be used.
  • Mammalian or other eukaryotic host cells such as those of yeast, filamentous fungi, plant, insect, amphibian or avian species, may also be useful for production of the proteins of the present invention. Propagation of mammalian cells in culture is per se well known. Examples of commonly used mammalian host cell lines are VERO and HeLa cells, Chinese hamster ovary (CHO) cells, and WI38, BHK, and COS cell lines, although other cell lines may be appropriate, e.g., to provide higher expression, desirable glycosylation patterns.
  • Clones are selected by using markers depending on the mode of the vector construction.
  • the marker may be on the same or a different DNA molecule, preferably the same DNA molecule.
  • the transformant may be screened or, preferably, selected by any of the means well known in the art, e.g., by resistance to such antibiotics as ampicillin, tetracycline.
  • polynucleotides of the invention may be inserted into the host cell by any means known in the art, including for example, transformation, transduction, and electroporation.
  • "recombinant host cells”, “host cells”, “cells”, “cell lines”, “cell cultures”, and other such terms denoting microorganisms or higher eukaryotic cell lines cultured as unicellular entities refer to cells which can be, or have been, used as recipients for recombinant vector or other transfer DNA, and include the progeny of the original cell which has been transformed. It is understood that the progeny of a single parental cell may not necessarily be completely identical in morphology or in genomic or total DNA complement as the original parent, due to natural, accidental, or deliberate mutation.
  • Transformation refers to the insertion of an exogenous polynucleotide into a host cell, irrespective of the method used for the insertion, for example, direct uptake, transduction, f-mating or electroporation.
  • the exogenous polynucleotide may be maintained as a non-integrated vector, for example, a plasmid, or alternatively, may be integrated into the host cell genome.
  • a DNA plasmid or RNA vector may encode a component of the immune system that is specific to an immune response following challenge with a peptide, wherein said peptide is encoded by a mycobacterial gene that is induced or up-regulated during high DOT conditions.
  • nucleic acid sequence eg. DNA plasmid, or RNA vector
  • An eighth aspect provides use of a peptide, an inhibitor, an antibody, an attenuated mycobacterium, an attenuated microbial carrier, a DNA sequence corresponding to the coding sequence of an induced or up-regulated gene or a fragment or variant or derivative of said DNA sequence, a DNA plasmid comprising said DNA sequence or said fragment or variant or derivative, an RNA sequence encoded by said DNA sequence or said fragment or variant or derivative, and/or an RNA vector comprising said RNA sequence, according to the present invention, in the manufacture of a medicament for treating or preventing a mycobacterial infection.
  • preventing includes reducing the severity/intensity of, or initiation of, a mycobacterial infection.
  • treating includes post-infection therapy and amelioration of a mycobacterial infection.
  • a method of treating or preventing a mycobacterial infection comprising administration of a medicament selected from the group consisting of a peptide, an inhibitor, an antibody, an attenuated mycobacterium, an attenuated microbial carrier, a DNA sequence corresponding to the coding sequence of an induced or up-regulated gene or a fragment or variant or derivative of said DNA sequence, a DNA plasmid comprising said DNA sequence or said fragment or variant or derivative, an RNA sequence encoded by said DNA sequence or said fragment or variant or derivative, and/or an RNA vector comprising said RNA sequence, according to the present invention, to a patient.
  • a medicament selected from the group consisting of a peptide, an inhibitor, an antibody, an attenuated mycobacterium, an attenuated microbial carrier, a DNA sequence corresponding to the coding sequence of an induced or up-regulated gene or a fragment or variant or derivative of said DNA sequence, a DNA plasmid comprising said DNA sequence or said fragment or variant or derivative, an
  • the medicament may be administered by conventional routes, eg. intravenous, intraperitoneal, intranasal routes.
  • the immunogenicity of the epitopes of the peptides of the invention may be enhanced by preparing them in mammalian or yeast systems fused with or assembled with particle-forming proteins such as, for example, that associated with hepatitis B surface antigen.
  • Vaccines may be prepared from one or more immunogenic peptides of the present invention.
  • such vaccines are prepared as injectables, either as liquid solutions or suspensions; solid forms suitable for solution in, or suspension in, liquid prior to injection may also be prepared.
  • the preparation may also be emulsified, or the peptide encapsulated in liposomes.
  • the active immunogenic ingredients are often mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipients are, for example, water, saline, dextrose, glycerol, ethanol, or the like and combinations thereof.
  • the vaccine may contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents, and/or adjuvants which enhance the effectiveness of the vaccine.
  • adjuvants which may be effective include but are not limited to: aluminum hydroxide, N-acetyl-muramyl-L-threonyl-D-isoglutamine (thr-MDP), N-acetyl-nor-muramyl-L-alanyl-D-isoglutamine (CGP 11637, referred to as nor-MDP), N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-(1'-2'-dipalmito yl-sn -glycero-3-hydroxyphosphoryloxy)-ethylam ine (CGP 19835A, referred to as MTP-PE), and RIBI, which contains three components extracted from bacteria, monophosphoryl lipid A, trehalose dimycolate and cell wall skeleton (MPL+TDM+CWS) in a 2% squalene/Tween 80 emulsion.
  • the vaccines are conventionally administered parenterally, by injection, for example, either subcutaneously or intramuscularly.
  • Additional formulations which are suitable for other modes of administration include suppositories and, in some cases, oral formulations or formulations suitable for distribution as aerosols.
  • traditional binders and carriers may include, for example, polyalkylene glycols or triglycerides; such suppositories may be formed from mixtures containing the active ingredient in the range of 0.5% to 10%, preferably 1%-2%.
  • Oral formulations include such normally employed excipients as, for example, pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, and the like. These compositions take the form of solutions, suspensions, tablets, pills, capsules, sustained release formulations or powders and contain 10%-95% of active ingredient, preferably 25%-70%.
  • the peptides may be formulated into the vaccine as neutral or salt forms.
  • Pharmaceutically acceptable salts include the acid addition salts (formed with free amino groups of the peptide) and which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or with organic acids such as acetic, oxalic, tartaric, maleic, and the like. Salts formed with the free carboxyl groups may also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, 2-ethylamino ethanol, histidine, procaine, and the like.
  • the vaccines are administered in a manner compatible with the dosage formulation, and in such amount as will be prophylactically and/or therapeutically effective.
  • the quantity to be administered which is generally in the range of 5 micrograms to 250 micrograms of antigen per dose, depends on the subject to be treated, capacity of the subject's immune system to synthesize antibodies, and the degree of protection desired. Precise amounts of active ingredient required to be administered may depend on the judgment of the practitioner and may be peculiar to each subject.
  • the vaccine may be given in a single dose schedule, or preferably in a multiple dose schedule.
  • a multiple dose schedule is one in which a primary course of vaccination may be with 1-10 separate doses, followed by other doses given at subsequent time intervals required to maintain and or re-enforce the immune response, for example, at 1-4 months for a second dose, and if needed, a subsequent dose(s) after several months.
  • the dosage regimen will also, at least in part, be determined by the need of the individual and be dependent upon the judgment of the practitioner.
  • the vaccine containing the immunogenic mycobacterial antigen(s) may be administered in conjunction with other immunoregulatory agents, for example, immunoglobulins, as well as antibiotics.
  • the outcome of administering antibody-containing compositions may depend on the efficiency of transmission of antibodies to the site of infection.
  • a mycobacterial respiratory infection eg. a M. tuberculosis infection
  • this may be facilitated by efficient transmission of antibodies to the lungs.
  • the medicament may be administered intranasally (i.n.).
  • This mode of delivery corresponds to the route of delivery of a M. tuberculosis infection and, in the case of antibody delivery, ensures that antibodies are present at the site of infection to combat the bacterium before it becomes intracellular and also during the period when it spreads between cells.
  • An intranasal composition may be administered in droplet form having approximate diameters in the range of 100-5000 ⁇ m, preferably 500-4000 ⁇ m, more preferably 1000-3000 ⁇ m.
  • the droplets would be in the approximate range of 0.001 -100 ⁇ l, preferably 0.1 -50 ⁇ l, more preferably 1.0-25 ⁇ l.
  • Intranasal administration may be achieved by way of applying nasal droplets or via a nasal spray.
  • the droplets may typically have a diameter of approximately 1000-3000 ⁇ m and/or a volume of 1-25 ⁇ l.
  • the droplets may typically have a diameter of approximately 100-1000 ⁇ m and/or a volume of 0.001-1 ⁇ l.
  • the medicament may be delivered in an aerosol formulation.
  • the aerosol formulation may take the form of a powder, suspension or solution.
  • the size of aerosol particles is one factor relevant to the delivery capability of an aerosol. Thus, smaller particles may travel further down the respiratory airway towards the alveoli than would larger particles.
  • the aerosol particles have a diameter distribution to facilitate delivery along the entire length of the bronchi, bronchioles, and alveoli.
  • the particle size distribution may be selected to target a particular section of the respiratory airway, for example the alveoli.
  • the aerosol particles may be delivered by way of a nebulizer or nasal spray.
  • the particles may have diameters in the approximate range of 0.1-50 ⁇ m, preferably 1-25 ⁇ m, more preferably 1-5 ⁇ m.
  • the aerosol formulation of the medicament of the present invention may optionally contain a propellant and/or surfactant.
  • the protective mechanisms invoked by the intranasal route of administration may include: the activation of T lymphocytes with preferential lung homing; upregulation of co-stimulatory molecules, eg. B7.2; and/or activation of macrophages or secretory IgA antibodies.
  • Intranasal delivery of antigens may facilitate a mucosal antibody response is invoked which is favoured by a shift in the T cell response toward the Th2 phenotype which helps antibody production.
  • a mucosal response is characterised by enhanced IgA production, and a Th2 response is characterised by enhanced IL- 4 production.
  • Intranasal delivery of mycobacterial antigens allows targeting of the antigens to submucosal B cells of the respiratory system. These B cells are the major local IgA- producing cells in mammals and intranasal delivery facilitates a rapid increase in IgA production by these cells against the mycobacterial antigens.
  • administration of the medicament comprising a mycobacterial antigen stimulates IgA antibody production, and the IgA antibody binds to the mycobacterial antigen.
  • a mucosal and/or Th2 immune response is stimulated.
  • monoclonal antibodies in particular, may be used to raise anti-idiotype antibodies.
  • Anti-idiotype antibodies are immunoglobulins which carry an "internal image" of the antigen of the infectious agent against which protection is desired. These anti-idiotype antibodies may also be useful for treatment, vaccination and/or diagnosis of mycobacterial infections.
  • the peptides of the present invention and antibodies to them are useful in immunoassays to detect the presence of antibodies to mycobacteria or the presence of the virulence associated antigens in biological samples.
  • Design of the immunoassays is subject to a great deal of variation, and many formats are known in the art.
  • the immunoassay may utilize at least one epitope derived from a peptide of the present invention.
  • the immunoassay uses a combination of such epitopes. These epitopes may be derived from the same or from different bacterial peptides, and may be in separate recombinant or natural peptides or together in the same recombinant peptide.
  • An immunoassay may use, for example, a monoclonal antibody directed towards a virulence associated peptide epitope(s), a combination of monoclonal antibodies directed towards epitopes of one mycobacterial antigen, monoclonal antibodies directed towards epitopes of different mycobacterial antigens, polyclonal antibodies directed towards the same antigen, or polyclonal antibodies directed towards different antigens. Protocols may be based, for example, upon competition, or direct reaction, or sandwich type assays. Protocols may also, for example, use solid supports, or may be by immunoprecipitation.
  • assays involve the use of labelled antibody or polypeptide; the labels may be, for example, enzymatic, fluorescent, chemiluminescent, radioactive, or dye molecules.
  • Assays which amplify the signals from the probe are also known; examples of which are assays which utilize biotin and avidin, and enzyme-labelled and mediated immunoassays, such as ELISA assays.
  • an immunoassay for an antibody(s) to a peptide will involve selecting and preparing the test sample suspected of containing the antibodies, such as a biological sample, then incubating it with an antigenic (ie. epitope-containing) peptide(s) under conditions that allow antigen-antibody complexes to form, and then detecting the formation of such complexes.
  • the immunoassay may be of a standard or competitive type.
  • the peptide is typically bound to a solid support to facilitate separation of the sample from the peptide after incubation. Examples of solid supports that can be used are nitrocellulose (eg. in membrane or microtiter well form), polyvinyl chloride (eg.
  • polystyrene latex eg. in beads or microtiter plates, polyvinylidine fluoride (known as Immulon), diazotized paper, nylon membranes, activated beads, and Protein A beads.
  • Immulon polyvinylidine fluoride
  • the solid support containing the antigenic peptide is typically washed after separating it from the test sample, and prior to detection of bound antibodies.
  • Complexes formed comprising antibody are detected by any of a number of known techniques, depending on the format.
  • unlabelled antibodies in the complex may be detected using a conjugate of antixenogeneic Ig complexed with a label (eg. an enzyme label).
  • the test sample typically a biological sample
  • antibodies directed against the peptide under conditions that allow the formation of antigen-antibody complexes. It may be desirable to treat the biological sample to release putative bacterial components prior to testing.
  • Various formats can be employed. For example, a "sandwich assay" may be employed, where antibody bound to a solid support is incubated with the test sample; washed; incubated with a second, labelled antibody to the analyte, and the support is washed again. Analyte is detected by determining if the second antibody is bound to the support.
  • a test sample is usually incubated with antibody and a labelled, competing antigen is also incubated, either sequentially or simultaneously.
  • an immunoassay kit comprised of one or more peptides of the invention, or one or more antibodies to said peptides, and a buffer, packaged in suitable containers.
  • a "biological sample” refers to a sample of tissue or fluid isolated from an individual, including but not limited to, for example, plasma, serum, spinal fluid, lymph fluid, the external sections of the skin, respiratory, intestinal, and genitourinary tracts, tears, saliva, milk, blood cells, tumours, organs, and also samples of in vitro cell culture constituents (including but not limited to conditioned medium resulting from the growth of cells in cell culture medium, putatively virally infected cells, recombinant cells, and cell components).
  • the present invention provides nucleic acid probes for detecting a mycobacterial infection.
  • oligomers of approximately 8 nucleotides or more can be prepared, either by excision from recombinant polynucleotides or synthetically, which hybridize with the mycobacterial sequences, and are useful in identification of mycobacteria.
  • the probes are a length which allows the detection of the induced or up-regulated sequences by hybridization. While 6-8 nucleotides may be a workable length, sequences of 10-12 nucleotides are preferred, and at least about 20 nucleotides appears optimal.
  • These probes can be prepared using routine methods, including automated oligonucleotide synthetic methods. For use as probes, complete complementarity is desirable, though it may be unnecessary as the length of the fragment is increased.
  • the biological sample to be analyzed such as blood or serum
  • the biological sample to be analyzed may be treated, if desired, to extract the nucleic acids contained therein.
  • the resulting nucleic acid from the sample may be subjected to gel electrophoresis or other size separation techniques; alternatively, the nucleic acid sample may be dot blotted without size separation.
  • the probes are usually labeled. Suitable labels, and methods for labeling probes are known in the art, and include, for example, radioactive labels incorporated by nick translation or kinasing, biotin, fluorescent probes, and chemiluminescent probes.
  • the nucleic acids extracted from the sample are then treated with the labeled probe under hybridization conditions of suitable stringencies.
  • the probes may be made completely complementary to the virulence encoding polynucleotide. Therefore, usually high stringency conditions are desirable in order to prevent false positives.
  • the stringency of hybridization is determined by a number of factors during hybridization and during the washing procedure, including temperature, ionic strength, length of time, and concentration of formamide.
  • amplification techniques in hybridization assays.
  • Such techniques include, for example, the polymerase chain reaction (PCR) technique.
  • PCR polymerase chain reaction
  • the probes may be packaged into diagnostic kits. Diagnostic kits include the probe DNA, which may be labeled; alternatively, the probe DNA may be unlabeled and the ingredients for labeling may be included in the kit in separate containers.
  • the kit may also contain other suitably packaged reagents and materials needed for the particular hybridization protocol, for example, standards, as well as instructions for conducting the test.
  • a peptide (or fragment or variant or derivative) of the present invention is used in a diagnostic assay to detect the presence of a T- lymphocyte, which T-lymphocyte has been previously exposed to an antigenic component of a mycobacterial infection in a patient.
  • a T-lymphocyte which has been previously exposed to a particular antigen will be activated on subsequent challenge by the same antigen.
  • This activation provides a means for identifying a positive diagnosis of mycobacterial infection.
  • the same activation is not achieved by a T-lymphocyte which has not been previously exposed to the particular antigen.
  • the above "activation" of a T-lymphocyte is sometimes referred to as a "recall response” and may be measured, for example, by determining the release of interferon (eg. IFN- ⁇ ) from the activated T-lymphocyte.
  • interferon eg. IFN- ⁇
  • the presence of a mycobacterial infection in a patient may be determined by the release of a minimum concentration of interferon from a T-lymphocyte after a defined time period following in vitro challenge of the T-lymphocyte with a peptide (or fragment or variant or derivative) of the present invention.
  • a biological sample containing T-lymphocytes is taken from a patient, and then challenged with a peptide (or fragment, variant, or derivative thereof) of the present invention.
  • the above T-lymphocyte diagnostic assay may include an antigen presenting cell (APC) expressing at least one major histocompatibility complex (MHC) class II molecule expressed by the patient in question.
  • the APC may be inherently provided in the biological sample, or may be added exogenously.
  • the T-lymphocyte is a CD4 T-lymphocyte.
  • M. tuberculosis strain H37Rv (NCTC cat. no. 7416) - a representative strain of M. tuberculosis.
  • Stock cultures were grown on Middlebrook 7H10 + OADC for 3 weeks at 37 ⁇ 2°C harvested and stored at -70X as a dense suspension in deionised water.
  • a chemically defined culture medium was developed, and was designated CAMR Mycobacterial Medium (see WO00/52139).
  • the medium was modified to provide a concentration of 0.8 g/l glycerol, prepared with high quality water from a Millepore water purification system and filter sterilised by passage through a 0.07 ⁇ m pore size cellulose acetate membrane filter capsule (Sartorius Ltd).
  • Middlebrook 7H10 + OADC agar was used to prepare inoculum cultures, enumerate the number of culturable bacteria in chemostat samples, and to assess culture purity.
  • Culture experiments were performed in a one litre glass vessel operated at a working volume of 500 ml.
  • the culture was agitated by a magnetic bar placed in the culture vessel coupled to a magnetic stirrer positioned beneath the vessel.
  • Culture conditions were continuously monitored and controlled by an Anglicon Microlab Fermentation System (Brighton Systems, Newhaven), linked to sensor probes inserted into the culture through sealed ports in the top plate.
  • the oxygen concentration was monitored with a galvanic oxygen electrode (Uniprobe, Cambridge) and was controlled through feedback control of the agitation rate.
  • Temperature was monitored by an Anglicon temperature probe, and maintained by a heating pad positioned beneath the culture vessel.
  • Culture pH was measured using an Ingold pH electrode (Mettler-Toledo, Leicester) and controlled by automatic addition of either sodium hydroxide (0.5 M) or sulphuric acid (0.5 M).
  • the culture system was operated by controlling nutrient addition from the medium reservoir and a constant culture volume was maintained by an overflow tube fitted to the side of the vessel. Inoculation and culture
  • the vessel was filled with 350 ml of sterile culture medium and parameters were allowed to stabilise at 37°C ⁇ 2°C, pH 6.9 ⁇ 0.2 and a dissolved oxygen tension of approximately 70% air saturation.
  • a dense inoculum suspension was prepared by resuspending Middlebrook agar cultures, grown at 37 ⁇ 2°C for 3 weeks, in sterile deionised water.
  • the inoculum was aseptically transferred to the culture vessel, to provide an initial culture turbidity of approximately 0.25 at 540 nm. After inoculation the culture was allowed to establish for approximately 50 h. As the culture entered exponential growth, a further 100 ml medium was added and batch growth was monitored by optical density and viable count determination.
  • the culture was inoculated and allowed to establish for approximately 50 h as detailed.
  • the culture was then operated in fed batch mode for 48 h with medium addition (approx. 100 ml) as the culture entered exponential growth and 24 h later.
  • Continuous culture was then initiated at a dilution rate of 0.03 h "1 [equivalent to a mean generation time (MGT) of 24 h].
  • Culture parameters were maintained at a dissolved oxygen tension (DOT) of 50 % (v/v) air saturation at 37 ⁇ 2°C and pH 6.9 ⁇ 0.2 for "high” dissolved oxygen culture conditions, and a DOT of 1 % (v/v) air saturation at 37 ⁇ 2°C and pH 6.9 ⁇ 0.2 for "low” dissolved oxygen culture conditions .
  • Growth was monitored by optical density, dry weight and viable count determination.
  • test sample data on each chip was normalised against the control data followed by per chip normalisation about the median intensity value, using the 50th percentile, and finally per gene normalisation across all the arrays.
  • the two data sets were averaged and compared and genes which were expressed at least 1.5- fold higher under aerobic relative to low-oxygen conditions were selected.
  • the gene identification numbers, and assigned functions are listed in Table 1.
  • the corresponding sequence data are listed in the accompanying sequence listing in which the amino acid sequence is given first followed by the nucleic acid coding sequence for each identified gene.
  • Trizol (Life Technologies) - formulation of phenol and guanidine thiocyanate.
  • GTC lysis solution containing: 5M guanidine thiocyanate, 0.5% N-lauryl sarcosine, 25mM tri-sodium citrate, 0.1 M 2-mercaptoethanol, and 0.5% Tween 80.
  • Steps performed at Containment level 2 5 * Precipitate the RNA at -70 °C for at least 30 min. (optionally overnight).
  • RNA was treated with DNAsel to remove genomic DNA and was then purified using RNeasy mini columns (Qiagen). Both methods were performed 5 according to the manufacturers guidelines.
  • the supernatant is removed and additional breaking buffer is added at a volume of 5 ml.
  • Beads are used to disrupt the cells. These are used at a quantity of 1 ml of beads for 1 ml of cells. Place the sample into the appropriate sized chamber. Place in the bead beater and secure the outer unit (containing ice) and process at the desired speed for 30 seconds.
  • Random primers (3 ⁇ g/ ⁇ l) 1 ⁇ l H 2 0 to 41.5 ⁇ l
  • Random primers (3 ⁇ g/ ⁇ l) 1 ⁇ l H 2 0 to 11 ⁇ l
  • Heat hybridisation solution at 95 °C for 2 min Do NOT snap cool on ice but allow to cool slightly and briefly centrifuge. Pipette the hybridisation solution onto the slide at the edge of the arrayed area avoiding bubble formation. Using forceps carefully drag the edge of a cover slip along the surface of the slide towards the arrayed area and into the hybridisation solution at the edge of the array. Carefully lower the cover slip down over the array avoiding any additional movement once in place. Seal the hybridisation cassette and submerge in a water bath at 65 °C for 16-20h.
  • Example 1 The materials and methods as described in Example 1 were repeated such that 500ml cultures of M. tuberculosis were established in a 1 litre glass vessel using CAMR Mycobacterial Medium at 37°C and 50% DOT.
  • the iron-replete medium in one of the above-mentioned steady state continuous cultures was then substituted with a medium that contained no added iron.
  • the mycobacterial culture became iron-limited, as indicated by a drop in cell density to an O.D. of approximately 1.0.
  • RNA extraction and microarray analysis were performed as described in Example 2. Thus, RNA extracted from aerobic (ie. 50% DOT) and iron-limiting cultures was compared with RNA extracted from aerobic (50% DOT) and non iron-limiting cultures.
  • the identified genes and corresponding peptides are illustrated in Table 2 (SEQ IDs 175-252, protein followed by nucleic acid).
  • Example 4 Delete one or more of the genes from M. tuberculosis in order to attenuate its virulence while retaining immunogenicity
  • genes that are identified may be disrupted using allelic exchange.
  • the gene of interest is cloned with 1 -2kb of flanking DNA either side and is inactivated by deletion of part of the coding region and insertion of an antibiotic resistance marker, such as hygromycin.
  • the manipulated fragment is then transferred to a suitable suicide vector e.g. pPR23 and is transformed into the wild-type parent strain of M. tuberculosis. Mutants are recovered by selecting for antibiotic resistant strains. Genotypic analysis (Southern Blotting with a fragment specific to the gene of interest) is performed on the selected strains to confirm that the gene has been disrupted.
  • the mutant strain is then studied to determine the effect of the gene disruption on the phenotype. In order to use it as a vaccine candidate it would be necessary to demonstrated attenuated virulence. This can be done using either a guinea pig or mouse model of infection. Animals are infected with the mutant strain and the progression of disease is monitored by determining the bacterial load in different organs, in particular the lung and spleen, at specific time points post infection, typically up to 16 weeks.
  • Example 5 Select one or more of our genes, which encode proteins that are immunogenic, and put them into BCG or an attenuated strain of M. tuberculosis to enhance its overall immunogenicity
  • the gene of interest is amplified from the M. tuberculosis genome by PCR.
  • the amplified product is purified and cloned into a plasmid (pMV306) that integrates site specifically into the mycobacterial genome at the attachment site (attB) for mycobacteriophage L5 [3].
  • BCG is transformed with the plasmid by electroporation, which involves damaging the cell envelope with high voltage electrical pulses, resulting in uptake of the DNA.
  • the plasmid integrates into the BCG chromosome at the attB site generating stable recombinants. Recombinants are selected and are checked by PCR or Southern blotting to ensure that the gene has been integrated. The recombinant strain is then used for protection studies.
  • Example 6 Use recombinant carriers such as attenuated salmonella and the Vaccinia virus to express and present TB genes.
  • MVA Modified Vaccinia virus Ankara
  • pSC11 Baby Hamster Kidney (BHK) cells are then infected with wild-type MVA and are transfected with the recombinant shuttle vector. Recombinant virus is then selected using a suitable selection marker and viral plaques, selected and purified.
  • Recombinant virus is normally delivered as part of a prime-boost regime where animals are vaccinated initially with a DNA vaccine encoding the TB genes of interest under the control of a constitutive promoter.
  • the immune response is boosted by administering recombinant MVA carrying the genes of interest to the animals at least 2 weeks later.
  • Example 7 Sub-unit vaccines containing a single peptide/protein or a combination of proteins
  • One of the common purification methods is to produce a recombinant protein with an N-terminal His-tag.
  • the protein can then be purified on the basis of the affinity of the His-tag for metal ions on a Ni-NTA column after which the His-tag is cleaved.
  • the purified protein is then administered to animals in a suitable adjuvant [5].
  • Example 8 Plasmid DNA vaccines carrying one or more of the identified genes
  • DNA encoding a specific gene is amplified by PCR, purified and inserted into specialised vectors developed for vaccine development, such as pVAXI .
  • vectors contain promoter sequences, which direct strong expression of the introduced DNA (encoding candidate antigens) in eukaryotic cells (eg. CMV or SV40 promoters), and polyadenlyation signals (eg. SV40 or bovine growth hormone) to stabilise the mRNA transcript.
  • the vector is transformed into E. coli and transformants are selected using a marker, such as kanamycin resistance, encoded by the plasmid.
  • a marker such as kanamycin resistance
  • the plasmid is then recovered from transformed colonies and is sequenced to check that the gene of interest is present and encoded properly without PCR generated mutations.
  • the plasmid is then produced in E. coli and the plasmid is recovered and purified using commercially available kits (eg. Qiagen Endofree-plasmid preparation).
  • the vaccine is then administered to animals for example by intramuscular injection in the presence or absence of an adjuvant.
  • DNA vaccines consist of a nucleic acid sequence of the present invention cloned into a bacterial plasmid.
  • the plasmid vector pVAXI is commonly used in the preparation of DNA vaccines.
  • the vector is designed to facilitate high copy number replication in E. coli and high level transient expression of the peptide of interest in most mammalian cells (for details see manufacturers protocol for pVAX1 ( catalog no. V260-20 www.invitrogen.com) .
  • the vector contains the following elements
  • CMV Human cytomegalovirus immediate-early
  • Bovine growth hormone (BGH) polyadenylation signal for efficient transcription termination and polyadenylation of mRNA
  • Vectors may be prepared by means of standard recombinant techniques which are known in the art, for example Sambrook et al., (1989). Key stages in preparing the vaccine are as follows:
  • the ligation mixture is then transformed into a competent E. coli strain (e.g. TOP10) and LB plates containing 50 ⁇ g/ml kanamycin are used to select transformants.
  • a competent E. coli strain e.g. TOP10
  • LB plates containing 50 ⁇ g/ml kanamycin are used to select transformants.
  • Clones are selected and may be sequenced to confirm the presence and orientation of the gene of interest.
  • the vector can be used to transfect a mammalian cell line to check for protein expression.
  • Methods for transfection include, for example, electroporation, calcium phosphate, and lipofection.
  • pVAXI does not integrate into the host chromosome. All non-essential sequences have been removed to minimise the possibility of integration.
  • a leader sequence may be included to direct secretion of the encoded protein when expressed inside the eukaryotic cell.
  • V1 Jns.tPA and pCMV4 Other examples of vectors that have been used are V1 Jns.tPA and pCMV4 (Lefevre et al. , 2000 and Vordermeier et al. , 2000).
  • Expression vectors may be used that integrate into the genome of the host, however, it is more common and more preferable to use a vector that does not integrate.
  • the example provided, pVAXI does not integrate. Integration would lead to the generation of a genetically modified host which raises other issues.
  • the vector construct (Example 9) may be used to generate RNA in vitro and the purified RNA then injected into the host.
  • the RNA would then serve as a template for translation in the host cell. In this embodiment. In this embodiment, integration would not occur.
  • Another option is to use an infectious agent such as the retroviral genome carrying RNA corresponding to the gene of interest. In this embodiment, integration into the host genome will occur.
  • RNA replicon vaccines which can be derived from virus vectors such as Sindbis virus or Semliki Forest virus. These vaccines are self-replicating and self-limiting and may be administered as either RNA or DNA which is then transcribed into RNA replicons in vivo. The vector eventually causes lysis of the transfected cells thereby reducing concerns about integration into the host genome. Protocols for RNA vaccine construction are detailed in Cheng, et al. (2001 ).
  • Example 11 Diagnostic assays based on assessing T cell responses
  • Mononuclear cells can be separated from the blood using density gradients such as Ficoll gradients.
  • Both monocytes and B-lymphocytes are both able to present antigen, although less efficiently than professional antigen presenting cells (APCs) such as dendritic cells.
  • APCs professional antigen presenting cells
  • dendritic cells The latter are more localised in lymphoid tissue.
  • the simplest approach would be to add antigen to the separated mononuclear cells and incubate for a week and then assess the amount of proliferation. If the individual had been exposed to the antigen previously through infection, then T-cell closes specific to the antigen should be more prevalent in the sample and should respond.
  • Another variation of this type of assay is to measure cytokine production by the responding lymphocytes as a measure of response.
  • the ELISPOT assay described below in Example 12 is a suitable example of this variation.
  • a major problem for the control of tuberculosis is the presence of a large reservoir of asymptomatic individuals infected with tubercle bacilli. Dormant bacilli are more resistant to front-line drugs.
  • latent mycobacteria-associated antigen may be detected indirectly either by detecting antigen specific antibody or T-cells in blood samples.
  • ESAT-6 a secreted antigen
  • a 96 well plate is coated with cytokine (e.g. interferon- ⁇ , IL-2) -specific antibody.
  • cytokine e.g. interferon- ⁇ , IL-2
  • Peripheral blood monocytes are then isolated from patient whole blood and are applied to the wells.
  • Antigen ie. one of the peptides, fragments, derivatives or variants of the present invention
  • the antigen stimulates cytokine production which then binds to the specific antibody.
  • the plates are washed leaving a footprint where antigen-specific T cells were present.
  • a second antibody coupled with a suitable detection system e.g. enzyme, is then added and the number of spots are enumerated after the appropriate substrate has been added.
  • the number of spots, each corresponding to a single antigen-specific T cell, is related to the total number of cells originally added.
  • Example 2 also describes use of an antigen that may be used to distinguish TB infected individuals from BCG vaccinated individuals. This could be used in a more discriminative diagnostic assay.

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Abstract

L'invention concerne un procédé permettant d'identifier des gènes mycobactériens dont l'expression est induite ou régulée positivement dans des conditions de culture continue caractérisées par une tension en oxygène dissous d'au moins 30 % de saturation en air mesurée à 37 °C, comparée à une tension en oxygène dissous allant jusqu'à 10 % de saturation en air, mesurée à 37 °C. Le procédé selon l'invention permet facultativement d'identifier des gènes mycobactériens simultanément induits ou régulés positivement dans des conditions de culture continue limitant le fer. Lesdits gènes induits ou régulés positivement forment la base de vaccins d'acides nucléiques ou constituent des cibles permettant de préparer des mycobactéries atténuées destinées à des vaccins contre les infections mycobactériennes. De même, les peptides codés par lesdits gènes induits ou régulés positivement sont utilisés dans des vaccins. Dans un autre mode de réalisation, les gènes/peptides identifiés constituent un moyen permettant d'identifier la présence d'une infection mycobactérienne dans un échantillon clinique, au moyen d'une sonde d'acide nucléique ou d'une détection d'anticorps.
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Cited By (22)

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GB2389364A (en) * 2002-06-07 2003-12-10 Agres Ltd Mycobacterial vaccines
US7608277B2 (en) * 2004-12-01 2009-10-27 Gene Therapy Systems, Inc. Tuberculosis nucleic acids, polypeptides and immunogenic compositions
EP2305701A1 (fr) * 2005-07-01 2011-04-06 Forsyth Dental Infirmary for Children Essais de détéction d'antigenes de la tuberculose et vaccins
US20110268758A1 (en) * 2005-07-01 2011-11-03 Antonio Campos-Neto Tuberculosis antigen detection assays and vaccines
WO2007087679A1 (fr) * 2006-01-31 2007-08-09 Proteome Systems Limited Procédé de diagnostic et de traitement d'une infection à m. tuberculosis et réactifs correspondants
EP2441469A1 (fr) * 2006-03-14 2012-04-18 Oregon Health and Science University Méthode pour produire une reponse contre la tuberculose
EP2207035A3 (fr) * 2006-03-14 2010-11-17 Oregon Health and Science University Procédés pour détecter une infection de tuberculose à mycobactérie
US8053181B2 (en) 2006-03-14 2011-11-08 Oregon Health & Science University Methods for detecting a Mycobacterium tuberculosis infection
US8101192B2 (en) 2006-03-14 2012-01-24 Oregon Health & Science University Methods for producing an immune response to tuberculosis
EP2397854A3 (fr) * 2006-03-14 2012-03-14 Oregon Health and Science University Procédés pour détecter une infection de tuberculose à mycobactérie
EP2207035A2 (fr) * 2006-03-14 2010-07-14 Oregon Health and Science University Procédés pour détecter une infection de tuberculose à mycobactérie
US8361707B2 (en) 2006-03-14 2013-01-29 Oregon Health & Science University Methods for detecting a Mycobacterium tuberculosis infection
US8440206B2 (en) 2006-03-14 2013-05-14 Oregon Health & Science University Methods for producing an immune response to tuberculosis
US9040233B2 (en) 2006-03-14 2015-05-26 Oregon Health & Science University Methods for detecting a Mycobacterium tuberculosis infection
US8961989B2 (en) 2009-11-20 2015-02-24 Oregon Health & Science University Methods for producing an immune response to tuberculosis
US9173930B2 (en) 2009-11-20 2015-11-03 Oregon Health & Science University Methods for detecting a mycobacterium tuberculosis infection
US9506922B2 (en) 2009-11-20 2016-11-29 Oregon Health & Science University Methods for producing an immune response to tuberculosis
US9717782B2 (en) 2009-11-20 2017-08-01 Oregon Health & Science University Methods for producing an immune response to tuberculosis
EP3263124A1 (fr) * 2009-11-20 2018-01-03 Oregon Health & Science University Procédés de génération de réponse immunitaire à la tuberculose
EP2502076B1 (fr) * 2009-11-20 2018-04-18 Oregon Health and Science University Procedes destines a detecter une infection par mycrobacterium tuberculosis
CN103122364A (zh) * 2011-11-21 2013-05-29 华中农业大学 抗结核抑制剂筛选的靶标基因Rv2498c及应用
US11801490B2 (en) 2015-09-18 2023-10-31 Chevron Phillips Chemical Company Lp Methods of preparing a catalyst

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