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WO1994014072A1 - Determination de reticulations de pyrimidium serique - Google Patents

Determination de reticulations de pyrimidium serique Download PDF

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Publication number
WO1994014072A1
WO1994014072A1 PCT/US1993/012321 US9312321W WO9414072A1 WO 1994014072 A1 WO1994014072 A1 WO 1994014072A1 US 9312321 W US9312321 W US 9312321W WO 9414072 A1 WO9414072 A1 WO 9414072A1
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Prior art keywords
antibody
pyd
crosslinks
dpd
sample
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PCT/US1993/012321
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English (en)
Inventor
Viola T. Kung
Baltazar Gomez, Jr.
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Metra Biosystems, Inc.
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Priority to JP51453694A priority Critical patent/JP3448295B2/ja
Priority to AU58514/94A priority patent/AU5851494A/en
Publication of WO1994014072A1 publication Critical patent/WO1994014072A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
    • C07K16/18—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/5308—Immunoassay; Biospecific binding assay; Materials therefor for analytes not provided for elsewhere, e.g. nucleic acids, uric acid, worms, mites
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/574—Immunoassay; Biospecific binding assay; Materials therefor for cancer
    • G01N33/57407—Specifically defined cancers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/574—Immunoassay; Biospecific binding assay; Materials therefor for cancer
    • G01N33/57484—Immunoassay; Biospecific binding assay; Materials therefor for cancer involving compounds serving as markers for tumor, cancer, neoplasia, e.g. cellular determinants, receptors, heat shock/stress proteins, A-protein, oligosaccharides, metabolites
    • G01N33/57488—Immunoassay; Biospecific binding assay; Materials therefor for cancer involving compounds serving as markers for tumor, cancer, neoplasia, e.g. cellular determinants, receptors, heat shock/stress proteins, A-protein, oligosaccharides, metabolites involving compounds identifable in body fluids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
    • G01N33/6887—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids from muscle, cartilage or connective tissue
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C19/00—Dental auxiliary appliances
    • A61C19/06—Implements for therapeutic treatment
    • A61C19/063—Medicament applicators for teeth or gums, e.g. treatment with fluorides

Definitions

  • the present invention relates to a method for assessing bone collagen breakdown in a huiuan subject, by assaying the level of peptide-free pyridinium crosslinks in a human blood fluid sample.
  • osteoporosis there are a variety of conditions in humans which are characterized by a high level of bone resorption and by an abnormal balance between bone formation and bone resorption.
  • these are osteoporosis, Paget's disease, and conditions related to the progress of benign and malignant tumors of the bone and metastatic cancers which have been transferred to bone cells from, for example, prostate or breast initial tumors.
  • Other conditions which are associated with changes in collagen metabolism include osteomalacial diseases, rickets, abnormal growth in children, renal osteodystrophy, and a drug-induced osteopenia. Irregularities in bone metabolism are often side effects of thyroid treatments and thyroid conditions per se , such as primary hypothyroidis and thyrotoxicosis as well as Cushing's disease.
  • the crosslinks take the form of compounds containing a central 3-hydroxy pyridinium ring in which the ring nitrogen is derived from the epsilon amino group of lysine or hydroxylysine (Fujimoto, 1978; Robins, 1982a; Gunja-Smith; Ogawa; Eyre).
  • the pyridinium crosslink compounds found in urine can be grouped into four general classes: (1) native free crosslinks having a molecular weight of about 400 daltons (Fujimoto) , (2) glycosylated crosslinks and crosslink peptide forms having a molecular weight of between about 550 and 1,000 daltons (Robins, 1983) , (3) crosslink peptide forms having a molecular weight between 1,000 and 3,500 daltons (Robins, 1983, 1984, 1987; Henkel; Eyre), and (4) crosslink peptide forms having a molecular weight greater than 3,500 daltons.
  • 4,973,666 and 5,140,103 disclose an assay for measuring bone resorption by detection in urine of certain peptide-linked pyridinium species associated with bone collagen. These are obtained from the urine of patients suffering from Paget's disease, a disease known to involve high rates of bone formation and destruction.
  • the assay relies on immunospecific binding of crosslink compounds containing the specific peptide fragment or extension with an antibody prepared against the crosslink peptide. It is not clear whether and how the concentration of crosslink peptide being assayed relates to total urinary crosslinks.
  • Robins has described a technique for measuring pyridinoline in urine by the use of an antibody specific to hydrolysed Pyd (Robins, 1986) .
  • the method has the limitation that the antibody was found to be specific for the hydrolized form of Pyd, requiring that the urine sample being tested first be treated under hydrolytic conditions.
  • the hydrolytic treatment increases the time and expense of the assay, and precludes measurements of other native pyridinium crosslinks.
  • PCT International Publication No. WO 91/10141 discloses a method of assessing bone collagen degradation in human subjects by measuring the level of native, peptide-free pyridinoline or deoxypyridinoline in non-hydrolyzed urine samples.
  • the method represents an improvement over earlier methods based on analysis of urine samples because it avoids the hydrolytic sample pretreatment employed previously. It would be desirable to assay bone collagen degradation levels in a human subject by measuring the level of pyridinium crosslink species in a blood fluid sample.
  • Such an assay could be integrated into an automated clinical system designed to assay a variety of serum analytes.
  • the approach also has the advantage that the measured levels would not have to be corrected for variation in sample volume, e.g., by determining a ratio of deoxypyridinoline/creatinine.
  • the present invention includes, in one aspect, a method of screening for the presence of a bone resorption disorder in a human subject.
  • a blood-fluid sample is obtained from a subject and is reacted with an antibody which is capable of reacting immunospecifically with pyridinium crosslinks selected from the group consisting of native free pyridinoline, native free deoxypyridinoline, or both native free pyridinoline and deoxypyridinoline, to form an immunocomplex between the antibody and such pyridinium crosslinks in the sample.
  • the amount of immunocomplex formed is measured to determine the concentration of the selected pyridinium crosslinks in the sample.
  • the subject is indicated as having such a bone resorption disorder if the determined concentration is above (i) 5 nM native free pyridinoline, (ii) 1 nM native free deoxpyridinoline, or (ii) 6 nM combined native free pyridinoline and dexoypyridinoline.
  • the blood fluid sample may be serum or plasma, for example.
  • the bone resorption disorders that are screened for by the method include disorders that are characterized by elevated levels of hydrolysed pyridinoline crosslinks in the urine.
  • the antibody in the method can be a monoclonal antibody or polyclonal antibody, and preferably has a binding constant with respect to the selected pyridinium crosslinks of at least 5 x 10 7 /molar.
  • the antibody used in the method has a ratio of reactivity toward the selected pyridinium crosslinks and urinary pyridinium peptides larger than 1,000 daltons in molecular weight, of greater than about 5:1.
  • the antibody has a ratio of reactivity toward the selected pyridinium crosslinks and urinary pyridinium peptides larger than 1,000 daltons in molecular weight, of greater than about 10:1, and more preferably, greater than 20:1.
  • the antibody is specific for native free pyridinoline, and has a ratio of reactivity toward native free pyridinoline and native free deoxypyridinoline of greater than about 5:1.
  • the monoclonal antibody is specific for native free deoxypyri ⁇ dinoline, and has a ratio of reactivity toward native free deoxypyridinoline and native free pyridinoline of greater than about 25:1.
  • the monoclonal antibody is specific for both native free pyridinoline and native free deoxypyridinoline and has a ratio of reactivity toward native free pyridinoline and native free deoxypyridinoline of between about 2:l and 1:2.
  • the ratio of reactivity toward native free pyridinoline and native free deoxy ⁇ pyridinoline can be from greater than 5:1 to less than 1:25, including all ratios in between.
  • the sample is contacted, in the presence of the antibody, with a selected pyridinium crosslink-coated solid support effective to compete with such selected crosslinks in the sample for binding to the antibody.
  • the amount of immunocomplex formed between the antibody and the selected pyridinium crosslinks in the sample is measured indirectly, by measuring the amount of antibody bound to the solid support.
  • the sample is contacted, in the presence of exogenous reporter- labeled or reporter-labelable selected pyridinium crosslinks, with a solid-phase support that is coated with a selected amount of pyridinium crosslinks, under conditions such that the selected pyridinium crosslinks from the sample compete with the exogenous crosslinks for binding to the immobilized antibody on the support.
  • the method may be used for monitoring treatment of a condition associated with an elevated level of collagen degradation, by monitoring changes in the concentration of the selected pyridinium crosslinks during such treatment.
  • the invention includes a method of monitoring the status of a human cancer which involves or has the potential to progress to a metastatic condition which involves abnormalities in bone resorption rates.
  • a blood-fluid sample is obtained from a subject and reacted with an antibody capable of reacting immunospecifically with pyridinium crosslinks selected from the group consisting of native free pyridinoline, native free deoxypyridinoline, or both native free pyridinoline and deoxypyridinoline, to form an immunocomplex between the antibody and such pyridinium crosslinks in the sample.
  • the amount of immunocomplex formed is measured to determine the concentration of the selected pyridinium crosslinks in the sample.
  • the method may be used for monitoring treatment of a cancer which is characterized by involvement of collagen degradation, by monitoring changes in the selected pyridinium crosslinks concentration during treatment of the cancer.
  • the invention includes a method of assaying bone collagen breakdown levels in a human subject.
  • a blood-fluid sample is obtained from a subject and is reacted with an antibody which is capable of reacting immunospecifically with pyridinium crosslinks selected from the group consisting of native free pyridinoline, native free deoxypyridinoline, or both native free pyridinoline and deoxypyridinoline, and where the antibody has a binding constant for said selected crosslinks of at least 10 8 / * ⁇ .olar, to form an immunocomplex between the antibody and such pyridinium crosslinks in the sample.
  • the amount of immunocomplex formed is measured to determine the concentration of the selected pyridinium crosslinks in the sample.
  • the subject is indicated as having such a bone resorption disorder if the determined concentration is above (i) 5 nM native free pyridinoline, (ii) l nM native free deoxpyridinoline, or (ii) 6 nM combined native free pyridinoline and deoxypyridinoline.
  • lower threshold values can be used in order to increase the likelihood of identifying individuals with elevated levels of bone degradation — for example, for detecting native free pyridinoline, a value of about 3 nM; for native free deoxypyri ⁇ dinoline, a value of about 0.5 nM, and for detecting the combined concentration of native free pyri ⁇ dinoline and deoxypyridinoline, a value of about 3.5 nM.
  • the invention includes an antibody having an affinity constant with respect to the above selected pyridinium crosslinks of at least 10 8 / ⁇ r ⁇ olar.
  • the antibody has a ratio of reactivity toward the selected pyridinium crosslinks and urinary pyridinium peptides larger than 1,000 daltons in molecular weight, of greater than about 3:1, and preferably greater than about 5:1.
  • the invention includes a diagnostic kit for use in the methods above. The method includes an antibody such as described above, and detection means for detecting the amount of immunocomplex formed by reaction of the antibody with the selected pyridinium crosslinks from a blood fluid sample.
  • the kit for use in the method is preferably effective to detect a blood pyridinoline concentration ("threshold concentration") of at least about 1 nM, and more preferably, at least 0.5 nM.
  • the kit is preferably effective to detect a blood deoxypyridinoline concentration of at least about 0.1 nM, and more preferably, at least about 0.05 nM.
  • the threshold concentration is preferably l.l nM, and more preferably, 0.6 nM.
  • the detection sensitivity of the kit allows detection of the selected pyridinium crosslinks concentration in a selected range, for example, 1-10 nM for pyridinoline, or 0.1-10 nM for deoxypyridinoline.
  • FIGS. 1A-1C illustrate steps in practicing one embodiment of the invention
  • Fig. 2 is a titration curve for an antibody suitable for detecting pyridinoline (N-Pyd) in a blood fluid sample;
  • Fig. 3 is a titration curve for an antibody suitable for detecting deoxypyridinoline (N-Dpd) in a blood fluid sample;
  • Fig. 4 shows concentrations of N-Dpd measured in serum samples from normal (control) subjects
  • Fig. 5 shows concentrations of serum Pyd measured in accordance with the present invention in healthy control patients and in cancer patients.
  • Pyd or “pyridinoline” or “free pyridinoline” refers to the crosslink compound shown at I below, where the ring N is derived from the e amino group of a hydroxylysyl residue
  • Dpd or “deoxy ⁇ pyridinoline” or “free deoxypyridinoline” refers to the crosslink compound shown at II below, where the ring nitrogen is derived from e amino group of a lysyl residue.
  • Free crosslinks refers to either compounds I or II or a mixture of the two, i.e., free of any peptide or glycosyl group attachments.
  • glycosylated pyridinoline or “glyco-Pyd” refers to glycosylated forms of compound I, wherein glycosyl groups are covalently bound to the aliphatic hydroxyl group of Pyd.
  • Two glyco-Pyd crosslinks which have been identified are Gal-Pyd and Glc-Gal- Pyd, which contain the acetals shown at III and IV below, respectively.
  • Pyd-peptides or “pyridinoline-peptides” refers to peptide-derivatized forms of compound I, in which one or more of the three amino acid residues in the compound is linked via a peptide linkage to additional amino acid residues.
  • Dpd- peptides or “deoxypyridinoline-peptides” refers to peptide-derivatized forms of compound II, in which one or more of the three amino acid residues in the compound is linked via a peptide linkage to additional amino acid residues.
  • Pyridinium-peptides refers to a mixture of Pyd-peptides and Dpd-peptides.
  • Pyd-peptides having a molecular weight greater than 1000 daltons or “Pyd-peptides (MW>1000)” refers to Pyd-peptides retained by a dialysis membrane having a 1,000 molecular weight cutoff.
  • Pyd crosslinks refers to the pyridinium crosslinks which contain compound I either in free or peptide-derivatized form. Pyd crosslinks include Pyd, glyco-Pyd and Pyd-peptides. Similarly, “Dpd crosslinks” refers to the pyridinium crosslinks which contain compound II either in free or peptide- derivatized form. “Dpd crosslinks” include Dpd and Dpd-peptides.
  • Pyridinium crosslinks refers to pyridinium crosslinks which contain compounds I and/or II in free and/or peptide-linked form.
  • Total Pyd or “T-Pyd” refers to total hydrolysed Pyd produced by hydrolyzing Pyd crosslinks to Pyd.
  • Total Dpd or “T-Dpd” refers to total hydrolysed Dpd produced by hydrolyzing Dpd crosslinks to Dpd.
  • Hydrolysed-Pyd of “H-Pyd” refers to Pyd produced by hydrolysing Pyd crosslinks in 6N HC1 at 110°C for 16 hours.
  • “Hydrolysed-Dpd” of “H-Dpd” refers to Dpd produced by hydrolysing Dpd crosslinks in 6N HC1 at 110°C for 16 hours.
  • N-Pyd refers to Pyd which has not been subjected to hydrolytic conditions.
  • N-Dpd refers to Dpd which has not been subjected to hydrolytic conditions.
  • “Native free” or “native, peptide-free” refers to a pyridinium compound having structure I or II (or both) shown above, and which has not been subjected to hydrolytic conditions.
  • Blood fluid refers to cell-free fluid and fractions thereof, obtained from blood, e.g., serum or plasma.
  • “Limit of detection” refers to a concentration of the selected pyridinium crosslinks that can be distinguished from a negative sample (i.e., a sample lacking the selected pyridinium crosslinks) . More specifically, the limit of detection is the selected concentration of the selected pyridinium crosslinks which gives rise to a signal that is different by at least two standard deviations from the signal observed for a negative sample. Thus a limit of detection of native free deoxypyridinoline of about
  • 0.05 nM implies the ability to detect concentrations of native free deoxypyridinoline of at least 0.05 nM.
  • the actual limit of detection may be lower than the specified limit, e.g., in the present example, an assay with a specified limit of detection of 0.05 nM may have an actual limit of detection of 0.02 nM.
  • Detection sensitivity refers to the range of analyte concentrations which can be reliably measured in a given assay procedure.
  • a detection sensitivity which allows detection of native free pyridinoline concentrations in the range 0.1-10 nM means that the assay procedure can detect concentrations of analyte of 0.1 nM, and can detect differences in the analyte concentration in the range 0.1-10 nM.
  • the actual range of detection for the assay may be broader than the specified range, e.g., in the present example, an assay method having a detection sensitivity in the range 0.1-10 nM may be able to detect and distinguish analyte concentrations in the range 0.05-20 nM.
  • antibody reagent monoclonal and polyclonal antibodies
  • antibodies which are specific for selected native free pyridinium crosslinks (either N-Pyd, N-Dpd, or both).
  • the antibodies have a ratio of reactivity toward the selected native free pyridinium crosslink and urinary pyridinium peptides larger than 1,000 daltons in molecular weight, of greater than about 3:1, and preferably greater than about 5:1.
  • the antibody preferably has a ratio of reactivity toward native free pyridinoline and native free deoxypyridinoline of greater than about 5:1, preferably greater than about 20:1, and more preferably greater than about 100:1.
  • the antibody preferably has a ratio of reactivity toward native free deoxypyridinoline and native free pyridinoline of greater than about 5:1, preferably greater than about 25:1, and more preferably greater than about 100:1.
  • the antibody preferably has a ratio of reactivity toward native free pyridinoline and native free deoxypyridinoline of between about 2:1 and 1:2.
  • the antibody reagent of the invention preferably has a binding affinity constant for the selected pyridinium species (N-Pyd or N-Dpd) of greater than about 5 x 10 7 /molar.
  • the immunogen used in producing the antibody reagent is Dpd or Pyd conjugated to a carrier molecule, typically a carrier protein such as keyhole limpet hemocyanin (KLH) .
  • a carrier protein such as keyhole limpet hemocyanin (KLH) .
  • the Pyd can be native Pyd (N-Pyd) or hydrolyzed Pyd (H-Pyd) .
  • the Dpd can be native Dpd (N- Dpd) or hydrolyzed Dpd (H-Dpd) .
  • N- Dpd native Dpd
  • H-Dpd hydrolyzed Dpd
  • gross separation of N-Dpd or N-Pyd from other pyridinium compounds in urine can be achieved by fractionation of urine, as described in Example 2. Briefly, a concentrate of urine is applied to a
  • hydrolyzed Pyd or Dpd can be produced by acid hydrolysis of pyridinium crosslinks in bone collagen or urine, purified as described in Black et al., 1988, for example.
  • Coupling of Pyd or Dpd to a carrier protein is by standard coupling methods, typically using a bifunctional coupling agent which forms, at one coupling end, an amide linkage to one of the free carboxyl groups of Pyd or Dpd, and at the other coupling end an amide or ester or disulfide linkage to the carrier protein, according to standard methods.
  • the Pyd or Dpd can be directly coupled to the protein, e.g., in the presence of a water-soluble carboxyl activating agent such as EDC (l-(3-dimethyl- aminopropyl)-3-ethylcarbodiimide) , also according to well known methods.
  • EDC l-(3-dimethyl- aminopropyl)-3-ethylcarbodiimide
  • Example 3 describes the coupling of Dpd to keyhole limpet hemocyanin (KLH) by EDC activation.
  • KLH keyhole limpet hemocyanin
  • the immunogen described above is used to immunize an animal, such as a mouse, from which antigen-specific lymphocytes can be obtained for immortalization.
  • an animal such as a mouse
  • antigen-specific lymphocytes can be obtained for immortalization.
  • One animal that has been found suitable is the "autoimmune" MRL/MpJ-lpr mouse available from Jackson Laboratory (Bar Harbor, MN) .
  • a Pyd-immunogen is typically used.
  • a Dpd-immunogen is typically used.
  • An antibody which recognizes both Pyd and Dpd may be obtained using a Pyd-immunogen or a Dpd-immunogen.
  • mice For producing a monoclonal antibody reagent which is specific for N- Pyd, mice can be immunized using a series of injections of H-Pyd-KLH immunogen, as outlined in Example 4. About 8 weeks after initial immunization, spleen cells are harvested and fused with a P3X63Ag8.653 myeloma cell line. Selection for successful fusion products can be performed in HAT in conditioned S-DMEM medium, according to published methods (see, generally, Harlow, pp. 196-212) .
  • the hybridoma cell line is grown in a suitable medium (Harlow, pp. 247-270), such as Dulbecco's modified Eagle's medium (DMEM) supplemented as described in the Materials and Methods section below.
  • DMEM Dulbecco's modified Eagle's medium
  • Mabs Monoclonal antibodies are harvested from the medium and can be concentrated and stored according to published methods (Harlow pp. 271-318) .
  • an important feature of the present invention is the specificity of the antibody reagent for N-Dpd and N-Pyd relative to larger molecular weight pyridinium crosslinks in urine.
  • the relative specificity of the antibody reagent for N- Pyd, N-Dpd, and other urinary pyridinium crosslinks can be determined by a competitive binding assays for N-Pyd, as detailed in Example 10.
  • various purified crosslink samples including N-Pyd and N-Dpd, as well as an amino acid mixture containing the 20 common amino acids in equimolar amounts (150 ⁇ M each), are reacted with a limiting amount of the antibody reagent over a solid- phase support having attached N-Pyd under conditions in which the pyridinium crosslinks in the sample compete with the support-bound N-Pyd for binding to the antibody.
  • the extent of binding of antibody to the solid-support provides a measure of the relative reactivities of the sample crosslinks for the antibody reagent.
  • Example 10 the levels of binding of N-Pyd, N-Dpd, Pyd-peptides (MW>1,000) , and an amino acid mixture (150 ⁇ M each of the common 20 amino acids) , to monoclonal antibodies from cell line Pyd XXV-3G6- 3B11-1A10 were examined.
  • the apparent Pyd concentration of each sample was determined using standard curves established using purified N-Pyd.
  • the percent reactivity of each sample was calculated as a ratio of apparent concentration (measured using the N-Pyd standard curve above) to total Pyd crosslink concentration in the sample determined by HPLC for total H-Pyd (times 100) , or to total Dpd- crosslink concentration as determined by HPLC for total H-Dpd (times 100) in the case of the N-Dpd sample.
  • the results are shown in Table 1, where reactivity with N-Pyd has been defined as 100%.
  • the monoclonal antibody reagent is highly selective for N-Pyd relative to N-Dpd, showing a ratio of reactivity toward native free pyridinoline and native free deoxypyridinoline that is greater than about 3:1, and in the present case, greater than 5:1.
  • the reagent is also selective for N-Pyd over the pyridinium-peptide forms tested (quantitated for total Pyd content) , showing a ratio of reactivity toward pyridinoline peptides larger than 1,000 daltons in molecular weight, of greater than about 100:1.
  • the reagent shows minimal cross reactivity ( ⁇ 1%) with the amino acid mixture tested.
  • the Mab reagent which is specific for N-Pyd has a reactivity toward native free pyridinoline (N-Pyd) and Pyd-peptides (MW>1000) , of greater than 5:1, preferably greater than 10:1, more preferably greater than 25:1, and in the present case, greater than 100:1, as measured by the above assay.
  • N-Dpd Monoclonal Antibody For producing a monoclonal antibody reagent which is specific for N- Dpd, the above procedure for obtaining N-Pyd Mabs can be used, except that Dpd-KLH is used as immunogen, and immunoreactivity screening is done with an assay for N-Dpd.
  • Dpd-KLH is used as immunogen
  • immunoreactivity screening is done with an assay for N-Dpd.
  • One subcloned cell line obtained by this procedure, and which gave high antibody affinity for N-Dpd is designated herein as Mab-Dpd-II-7B6-lF4- 1H11 (see Example 5) .
  • the antibody reagent is prepared from the hybridoma cell line and stored by the same general procedures described above for N-Pyd Mabs.
  • the relative specificity of the antibody reagent for N-Dpd, N-Pyd, and other urinary pyridinium crosslinks can be determined by the approach described above (section B.l), but using a solid- phase support having attached N-Dpd.
  • 1F4-1H11 were examined.
  • the apparent Dpd concentration of each sample was determined using standard curves established using purified N-Dpd.
  • the percent reactivity of each sample was calculated as a ratio of apparent N-Dpd concentration (measured using the N-Dpd standard curve above) to total Dpd- crosslink concentration in the sample determined by HPLC for total H-Dpd (times 100) , or to total Pyd- crosslink concentration as determined by HPLC for total H-Pyd (times 100) in the case of the N-Pyd sample.
  • the results are shown in Table 2, where reactivity with N-Dpd has been defined as 100%.
  • the monoclonal antibody reagent is highly selective for N-Dpd relative to N-Pyd, showing a ratio of reactivity toward native free deoxypyridinoline and native free pyridinoline that is greater than about 100:1.
  • the reagent is also selective for N-Dpd over the pyridinium-peptide forms tested (quantitated for Dpd content) , showing a ratio of reactivity toward deoxypyridinoline peptides larger than 1,000 daltons in molecular weight, that is greater than about 3:1, and preferably, greater than about 5:1.
  • the reagent shows minimal cross reactivity ( ⁇ 1%) with the amino acid mixture tested.
  • the Mab reagent which is specific for Dpd has a reactivity toward native pyridinoline (N-Dpd) and Dpd-peptides (MW>1000) , of greater than about 5:1, preferably greater than 10:1, more preferably greater than 25:1, and in the present case, greater than 100:1, as measured by the above assay.
  • B.3 Monoclonal Antibodies Which Bind N-Pvd and N-Dpd With Comparable Affinities For producing a monoclonal antibody reagent which binds N-Pyd and N- Dpd with comparable affinity, the procedures described above for obtaining N-Pyd Mabs and N-Dpd Mabs can be used.
  • the immunogen may be Pyd-KLH or Dpd-KLH, and immunoreactivity screening is done with separate assays for N-Pyd and N-Dpd.
  • the antibody reagent is prepared from the hybridoma cell line and stored by the same general procedures described above for the N-Pyd Mabs.
  • the relative specificity of the antibody reagent for N-Dpd, N-Pyd, and other urinary pyridinium crosslinks can be determined by the procedure described above (sections B.l and B.2).
  • the percent reactivity of each sample was calculated as a ratio of apparent N-Dpd concentration (measured using the N-Dpd standard curve above) to total Dpd crosslink concentration in the sample determined by HPLC for total H-Dpd (times 100) , or to total Pyd crosslink concentration determined by HPLC for total H-Pyd in the case of the N-Pyd sample.
  • Table 3 where reactivity with N-Dpd has been defined as 100%.
  • the monoclonal antibody reagent recognizes N-Dpd and N-Pyd with comparable affinities, with a cross-reactivity ratio close to 1:1.
  • the reagent is also selective for N-Dpd over the pyridinium-peptide forms tested (both Pyd and Dpd peptides) , showing a ratio of reactivity toward pyridinium peptides larger than 1,000 daltons in molecular weight, of greater than about 3:1, and in the present case, greater than 9:1.
  • the reagent shows minimal cross reactivity (5%) with the amino acid mixture tested.
  • the Pyd/Dpd-specific Mab reagent has a reactivity toward native free pyridinoline (N- Pyd) and native free deoxypyridinoline (N-Dpd) of between about 2:1 and 1:2.
  • Polyclonal antibody preparation is by conventional techniques, including injection of the immunogen into suitable mammalian subjects, such as rabbits or mice, according to immunological protocols generally known in the art, e.g., Harlow, pp. 93-115.
  • rabbits are injected subcutaneously with the immunogen in an adjuvant, and booster immuniz ⁇ ations are given by subcutaneous or intramuscular injection every 2-3 weeks; mice may be injected intraperitoneally according to a similar schedule. Blood is collected at intervals, e.g. 1-2 weeks after each immunization injection.
  • Antisera may be titrated to determine antibody formation with respect to N-Pyd or N-Dpd, according to standard immuno- precipitation methods (Harlow, pp. 423-470) .
  • the binding affinity constant for polyclonal antisera can be determined by known methods (e.g., by Scatchard analysis using an immunoprecipitation or ELISA assay; see Campbell, Segel) , and represents an average binding affinity constant value for the antibodies in the antisera which are specific against the selected pyridinium species.
  • Polyclonal antibodies obtained from rabbit VI-8 have a binding constant for N-Pyd of about 1 x 10 8 , as determined by Scatchard analysis.
  • the relative binding specificity of the antibody reagent for the selected pyridinium species and for other pyridinium crosslinks can be determined by a competitive binding assay such a ⁇ described above and detailed in Example 14. Table 4 shows the relative binding specificities of anti-Pyd antiserum obtained from rabbit VI-8, where reactivity with N-Pyd has been defined as 100%.
  • the antibody reagent is specific for N- Pyd, showing less than 10% cross-reactivity with N- Dpd, less than 5% cross-reactivity with Pyd-peptides (MW>1000) , and moderate (-12%) cross-reactivity with the amino acid mixture.
  • the polyclonal antibody reagent has a reactivity toward a selected native free pyridinium species (N-Pyd, N-Pyd, or both) and urinary pyridinium peptides larger than 1,000 daltons in molecular weight, of greater than 3:1, and preferably greater than about 5:1, as measured by the above antigen-competition assay.
  • the invention includes a diagnostic kit for use in assaying bone collagen degradation levels in a human subject.
  • the kit includes an antibody reagent of the type described in the section above, which preferably has a binding constant for native free deoxypyridinoline of greater than about 5 x 10 7 /molar, and more preferably, greater than 8 x l ⁇ 8 /molar.
  • the kit may also include detection means for detecting the amount of immunocomplex formed by reaction of the antibody reagent with selected pyridinium crosslinks, where the detection means is effective to measure the level of the selected crosslinks in a blood fluid sample.
  • a specific embodiment of such a kit, for measuring N-Pyd in a sample is shown at 10 in Figs.
  • a solid-phase support 12 in the kit has a surface to which the binding agent can be adsorbed or chemically attached.
  • a variety of glass and polymer resin supports having chemically derivatizable groups, or surfaces effective in protein adsorption are available.
  • the kit provides 96 assay wells in a microtitre plate, where the well surfaces form the solid-phase support surfaces in the kit.
  • the binding agent in kit 10 is N-Pyd, indicated by Pyd(N) molecules in the figures, such as at 16.
  • the binding agent is attached to the solid phase, in this case, each of the wells in a 96-well microtitre plate, by first adsorbing an porcine serum albumin- biotin complex, such as complex 18 in Fig. 1A, to the well surfaces, then attaching an N-Pyd-streptavidin complex, such as complex 20, to the adsorbed biotin.
  • the antibody reagent in the kit is indicated at 22 in Figs. IB and IC, and includes the polyclonal or monoclonal reagent described in the section above. As shown in Fig.
  • pyridinium crosslinks in a sample such as the N-Pyd crosslink indicated at 26, competes with surface-bound N-Pyd for binding to the antibody reagent.
  • the immunocomplex formed by reaction of the antibody reagent with sample crosslinks is indicated at 28 in this figure.
  • the detection reagent (detection means) in the kit is a reporter-labeled second antibody, indicated at 24 in Fig. IC, which is effective to bind to antibody reagent which is itself bound to N-Pyd attached to the solid support.
  • Reporter-labeled antibodies such as enzyme-labeled antibodies, are commercially available or readily constructed (Harlow, pp. 319-358) for a variety of reporter moieties.
  • One preferred enzyme in an enzyme-labeled antibody is alkaline phosphatase, which can react with a p-nitrophenylphosphate substrate to produce a colored product having a strong absorption peak at 405 nm.
  • the reporter-labeled second antibody is typically an anti-IgG antibody, such as an anti- rabbit IgG antibody, where the polyclonal antibody reagent in the kit is obtained from immunized rabbits, or an anti-mouse IgG antibody, where the antibody reagent is a mouse monoclonal antibody.
  • the antibody reagent (which is immunoreactive with N-Pyd as above) is "reporter-labelable", since the antibody reagent can become labeled by reaction with the reporter-labeled second antibody.
  • Other instances of a reporter-labelable antibody reagent include a biotin- or streptavidin-labeled antibody which can be reacted with a reporter-labeled streptavidin or biotin-labeled partner for detection purposes.
  • the detection reagent can be the anti-Pyd antibody reagent itself, labeled with a reporter, such as an enzyme.
  • the detection means in the kit may also include necessary substrates or the like needed for detection of the reporter in the reporter-labeled antibody.
  • the binding agent attached to the support is an anti-Pyd antibody reagent such as described in Section II.
  • the antibody may be attached to the solid support by a variety of known methods, including chemical derivatization or high-affinity binding of the antibody by support-bound protein A or anti-IgG antibody, according to standard methods.
  • the kit may additionally include a deoxypyridinoline reagent which is effective to compete with native free deoxypyridinoline in a sample for binding to the antibody reagent on the support.
  • the deoxypyridinoline reagent may include a reporter-label attached covalently to deoxypyridinoline (i.e., the reagent can be a reporter-labeled deoxypyridinoline) .
  • the reagent can be a reporter-labeled deoxypyridinoline
  • the deoxypyridinoline reagent may be reporter-labelable, in that the deoxypyridinoline reagent can include Pyd conjugated to an agent such as biotin or streptavidin, for example, for recognition by a corresponding reporter-labeled streptavidin or biotin molecule.
  • an agent such as biotin or streptavidin, for example, for recognition by a corresponding reporter-labeled streptavidin or biotin molecule.
  • the kit is designed for a homogenous assay in which sample deoxypyridinoline can be detected directly in solution.
  • kit of the invention can be adapted to a number of other assay formats, including formats based on radiotracers, coupled enzymes, fluorescence, chemiluminescence, or an EMIT configuration (Gosling) , for example.
  • the detection means in the kit includes a radioactive reporter group effective to produce a radioactive signal in proportion to the amount of immunocomplex formed by reaction of the antibody reagent with native free Pyd.
  • kits for assay of N-Pyd, it can be appreciated that a similar format can be used where the kit is for measurement of N- Dpd, using an N-Dpd specific antibody reagent, or for measurement of the sum of N-Pyd and N-Dpd, using an antibody reagent which binds N-Pyd and N-Dpd with comparable affinities.
  • the kit has a limit of detection for N-Pyd 1 nM or less, preferably 0.5 nM, and more preferably 0.2 nM. Fig.
  • Example 2 shows an N-Pyd titration curve carried out with the immunoassay format described in Example 13, using polyclonal antiserum obtained from rabbit VI-8 characterized in Table 4.
  • the kit affords a sensitivity of about 0.2 nM, while also providing reliable measurements of N-Pyd extending beyond 10 nM.
  • the kit preferably has a limit of detection for N-Dpd of 0.1 nM or less, preferably 0.05 nM, and more preferably 0.02 nM.
  • Fig. 3 shows an N-Dpd titration curve carried out with the immunoassay format described in Example 9, using monoclonal antibodies obtained from the hybridoma cell line 13D4 noted above.
  • the kit affords a limit of detection of about 0.02-0.05 nM, while also providing reliable measurements of N-Dpd extending up to about 10 nM.
  • the limit of detection in the kit can be selected such that only pyridinium crosslinks levels in a range considered to be above normal are detected, while those falling within generally normal levels are not detected in the assay.
  • the present invention provides a method of assaying bone collagen breakdown levels in a human subject, as outlined in the section above entitled "Summary of the Invention.”
  • the blood fluid sample is preferably pretreated to remove potentially interfering substances, prior to assay of the sample.
  • pretreat ent may be accomplished by trichloroacetic acid precipitation, wherein the sample is mixed 10:1 with 50% trichloroacetic acid, and then centrifuged to remove the precipitate.
  • the sample may be passed through a protein A column or contacted with Staphylococcus aureus cells (e.g., PANSORBIN cells, available from Calbiochem, San Diego, CA) to remove immunoglobulins and the like.
  • the sample is filtered to remove sample components having a molecular weight of greater than about 30 kDa. Such filtration may be accomplished by centrifugation using a Centricon-30 filtration device (Amicon, Mass.).
  • reaction of sample with the antibody reagent may be carried out in a solid-phase format, using a variety of configurations, or in a homogeneous assay format.
  • the immunoassay method will be described with particular reference to an assay format for assaying native free deoxypyridinoline in serum, in accordance with Example 9, wherein the solid support has surface- attached anti-Dpd antibodies, and exogenous enymze- labeled deoxypyridinoline capable of competing with native free deoxypyridinoline from the sample for binding to the support-bound anti-Dpd antibody. It will be appreciated how the method can be adapted to other solid-phase or homogeneous assay formats.
  • a known volume e.g., 100 ⁇ l, of the filtered or precipitated serum sample is added to an anti-Dpd- antibody-coated solid support, e.g., the wells in a microtitre plate prepared as in Example 8.
  • Sample addition is followed by addition of a known volume, typically 50-200 ⁇ l, of reporter-labeled Dpd at a known dilution.
  • the reporter-labeled Dpd is an alkaline phosphatase-Dpd conjugate, i.e., enzyme-labeled Dpd.
  • the mixture on the solid support surface is then incubated, preferably under conditions effective to achieve equilibrium for binding of the anti-Dpd antibody with sample Dpd and enzyme-labeled Dpd.
  • the incubation is overnight at 4°C.
  • N-Dpd standards containing increasing concentrations of N-Dpd are added in duplicate to some of the wells, for purposes of generating an N-Dpd concentration standard curve. Up to 40 samples are then added in duplicate to remaining wells, and the wells are then assay as above. The standard curve is used for determining pyridinium crosslink values for the samples in terms of N-Dpd concentrations.
  • the immunoassay method, antibody reagent, and kit of the invention, described above, are useful in assaying the level of collagen breakdown activity in a human subject.
  • the invention is useful in detecting increased blood levels of Pyd and Dpd associated with bone collagen breakdown conditions in general.
  • Such conditions may include osteoporosis, Paget's disease, hypothyroidism, osteoarthritis, and rheumatoid arthritis, for example.
  • Other conditions involving increased native free pyridinium crosslinks levels include various forms of metastatic cancer which become established in bone tissue or which otherwise alter bone metabolism.
  • Fig. 4 shows N-Dpd levels measured in serum samples from healthy (control) patients (column 1) , and in serum samples from patients with primary hyperparathyroidism (column 2) , osteomalacia (column 3) , calcium metabolism disorder (column 4) , and osteoporosis (column 5) .
  • the study was carried out using the assay protocol described in Example 9, with antibodies from hybridoma cell line 13D4 (see Table 2 above) .
  • N-Dpd levels in the control group were between about 0.2 and 0.5 nM, with an average level ( ⁇ standard deviation) of 0.33 ⁇ 0.07 nM.
  • the osteomalacia group showed levels between about 0.5 and 2.6 nM (mean 1.2 nM) ; the calcium metabolism disorder group showed levels between about 0.4 and 1.4 nM (mean 0.9 nM) ; and the osteoporosis group showed levels between about 0.3 and 1.1 nM (mean 0.6 nM) .
  • FIG. 4 data from the diseased groups as a whole are consistent with increased collagen breakdown in these patients.
  • the results show that serum N-Dpd levels above about 0.8 nM, and more preferably, above about 0.5 nM, are a useful indicator of increased collagen breakdown in such patients.
  • Figure 5 compares N-Pyd levels measured in serum samples from a group of healthy patients (group 1) with levels measured in samples from a group of cancer patients with established or suspected bone metastases. The study was carried out using the assay protocol described in Example 13, with antibodies from rabbit VI-8 characterized above in Table 4. As can be seen from the Figure, N-Pyd levels in the control group were between about 1 and 3 nM, with an average level ( ⁇ standard deviation) of 1.7 ⁇ 0.4 nM.
  • the cancer group showed levels between about 2 and 13 nM, with one patient showing a level of about 23 nM, consistent with increased collagen breakdown in these patients.
  • the results show that serum N-Pyd levels above about 5 nM, more preferably above about 3 nM, is a useful indicator of increased collagen breakdown in such patients.
  • the assay method allows measurement of native free pyridinium crosslink levels to be integrated with other clinical tests with blood samples.
  • the approach also avoids the correction for variation in sample volume typically needed where the sample is a urine sample (e.g., determination of urinary creatinine) .
  • the assay utilizes an antibody reagent, and can thus be adapted to a number of convenient and rapid assay formats, such as described above.
  • the invention can be used both for detecting increased collagen degradation in a patient, and also for monitoring the course of therapy of a variety of collagen-pathology states.
  • the following examples illustrate methods of producing antibody reagents and assay methods in accordance with the invention. The examples are intended to illustrate, but in no way limit, the scope of the invention.
  • mice Female autoimmune MRL/MpJ-lpr mice were purchased from the Jackson Laboratory, Bar Harbor, Maine.
  • Mouse non-secreting P3X63Ag8.653 myeloma cells, and mouse monocyte-macrophage cell lines P388D1(IL-1) and J774A.1 were purchased from American Type Culture Collection (ATCC) , Rockville, Maryland.
  • Adjuvant Ribi and Ribi(CWS) were purchased from RIBI Immunochem Research, Inc., Hamilton, Montana. 50% PEG 1500 (polyethylene glycol 1500, 50% (w:v) in water) was purchased from Boehringer Mannheim, Indianapolis, Indiana. HAT and HT were purchased from Sigma Chemical Company, St. Louis, Missouri.
  • Dulbecco's Modified Eagle Medium (DMEM) , NCTC- 109, and gentamicin were purchased from Gibco, Grand Island, New York. Fetal clone bovine serum was from Hyclone Laboratories, Inc., Logan, Utah. Oxaloacetic acid and insulin were from Sigma Chemical Company. S-DMEM was formulated as follows, where the percentages indicate final volume percentages in the final medium: DMEM (80%), NCTC-109 (10%), fetal clone bovine serum (10%) , oxaloacetic acid (1 mM) , L- glutamine (2 mM) , gentamicin (50 ⁇ g/ml) and insulin (10 ⁇ g/ml) .
  • mouse monocyte cell lines P388D1 (IL-1) , or interchangeably, cell line J774A.1
  • S- DMEM medium For preparation of conditioned media, mouse monocyte cell lines P388D1 (IL-1) , or interchangeably, cell line J774A.1, were grown in S- DMEM medium, with a 1:4 split twice a week. Every 3 days, tissue culture supernatants were filtered through a 0.2 micron filter and then supplemented with 4 mM L-glutamine. The resultant concentrated conditioned media were used as 20% supplement for S- DMEM to raise hybridoma cells.
  • IL-1 mouse monocyte cell lines P388D1
  • J774A.1 cell line J774A.
  • PBS is defined as a buffer containing 0.01 M phosphate and 150 mM NaCl, pH 7.
  • Example 1 HPLC Measurement of Crosslinks HPLC analysis for Pyd and Dpd was done essentially as described in Black (1988) . Briefly, urine samples were adjusted with butanol and glacial acetic acid to 4:1:1 (v:v:v) mixture and applied onto CFl cellulose (Whatman) cartridge, followed by a wash with 4:1:1 (butanol:acetic acid:water) solution. Only free crosslinks were retained. The free crosslinks were eluted from CFl cellulose with water.
  • Eluted material was analyzed on a C18 reverse phase column (Rainin, C18-80-200-C3) using a water- acetonitrile (3-17% in 10 minutes) gradient delivered at 1 ml/minute and monitoring fluorescence at 295 nm of excitation, 395 nm of emission.
  • Mobile phase contained 0.1% HFBA.
  • Concentrated urine was then applied onto Sephadex G-10 2.6 x 95 cm column equilibrated with 0.2 M acetic acid. Elution from the column material was analyzed for free Pyd and Dpd as described above. The free crosslink containing fractions were pooled together, adjusted to pH 2.0 and applied onto 1 x 18 cm cation exchange column (Lacarte Co., UK) and equilibrated with 0.1 M sodium citrate pH 4.2.
  • Glyco-Pyd, Pyd and Dpd were coeluted thereafter from the ion exchange column with 0.1 M sodium citrate pH 4.2. Collected fractions were analyzed for the presence of crosslinks by HPLC analysis as above. Fractions containing specific crosslinks (glyco-Pyd, Pyd and Dpd) were pooled together and applied onto 2.5 x 10 cm reverse phase C18 column (Waters) which was subsequently developed with 2-20% gradient of acetonitrile containing 0.1% HFBA. Separated fractions (glyco-Pyd, Pyd and Dpd) were collected and concentrated by lyophilization. Dry residue was reconstituted in 0.2 M acetic acid and stored at 4°C.
  • Urinary crosslink-peptides were prepared by exhaustive dialysis of human urine using 1000 D molecular weight cut off dialysis membranes (Spectra- Por) .
  • the T-Pyd and T-Dpd crosslink content of the peptide fractions was determined by hydrolyzing peptide samples with 6N HCl at 110°C for 16 hours followed by HPLC analysis for Pyd and Dpd.
  • H-Pyd and H-Dpd were obtained from hydrolyzed powdered bovine or sheep bone as described by Black et al . (1988).
  • Example 3 Preparation of Immunogens The following procedures illustrates how immunogens can be prepared for obtaining monoclonal or polyclonal antibodies against native free pyridinoline, native free deoxypyridinoline, or both.
  • the procedures in A and B below are described with respect to Pyd-immunogens; Dpd-immunogens are prepared the same way, but using Dpd instead of Pyd.
  • mice Female 5-week-old autoimmune MRL/MpJ-lpr mice were immunized using the protocol below:
  • the immunized mouse was sacrificed by C0 2 gas, and the spleen was excised from the mouse and placed in a culture dish containing 5 ml of serum-free DMEM medium preheated to 37°C. Following removal of adipose tissue attached to the spleen, the spleen was washed with 5 ml of serum-free DMEM medium. The spleen was then cut into small pieces which were placed in a cell homogenizer containing 7 ml of serum-free DMEM medium, and the cells were homogenized to form a cell suspension.
  • the spleen cell suspension ( ⁇ 2 x 10 8 cells in serum-free DMEM medium) and log-phase P3X63Ag8.653 myeloma cells (-7 x 10 7 cells in serum-free DMEM medium) were centrifuged independently at 400xg for 10 min.
  • the resultant cell pellets were suspended together in serum-free DMEM medium (10 ml) in a 50 mL centrifuge tube and then centrifuged at 400xg for 10 min. The supernatant was removed completely, and the centrifuge tube was tapped to loosen the cell pellet.
  • a solution of 50% PEG 1500 (4 ml) was added dropwise to the tube with gentle mixing by pipette over a 90 second period.
  • Anti-Dpd monoclonal antibodies were prepared by the procedure described in Example 4, using Dpd-KLH immunogen prepared as in Example 3.
  • the mouse immunization procedure was the same as in Example 4, except that Ribi(CWS) was used as adjuvant instead of Ribi, and 75 ⁇ g Dpd-immunogen per mouse was used in the fourth immunization step (18 days from fusion) instead of 100 ⁇ g.
  • Successful fusion products were screened for immunoreactivity using the N-Dpd immunoassay format described in Example 9.
  • Alkaline phosphatase-H-Dpd conjugate was prepared using bis(sulfosuccinimidyl) suberate (BSSS) as a coupling agent.
  • BSSS bis(sulfosuccinimidyl) suberate
  • BSSS (Pierce, Rockford, IL) dissolved in 50 ⁇ L DMSO (dimethylsulfoxide) .
  • DMSO dimethylsulfoxide
  • the reaction vessel was covered to exclude light, and the coupling reaction was allowed to proceed at room temperature for 2 hours.
  • the reaction was then quenched by adding 500 ⁇ l of 10 mM glycine (in 0.1 M phosphate buffer pH 7.5) and allowing the mixture to incubate for another 2 hours at room temperature, covered from light.
  • the quenched reaction mixture was then dialyzed against four changes of PBS (2 L each, at four hour intervals) at 4°C in darkness.
  • the stoichiometry of Dpd to AP in the dialyzate was determined spectrophotomerrically by measuring the absorbances at 326 nm and 280 nm.
  • the ratio of Dpd to AP was typically from 1:1 to 2:1.
  • the enzymatic activity of the AP-H-Dpd conjugate was determined as a percent of the activity of native AP in a standard AP assay.
  • Example 8 Preparation of Anti-Dpd-Antibody Coated Plates 96-well ELISA plates were coated as follows. 200 ⁇ l of a solution containing 3 ⁇ g/ml rabbit anti- mouse IgG in PBS containing 0.05% NaN 3 were added to each well, and the plates were incubated 18-24 hours at room temperature. After the incubation, the plates were washed 3x with 300 ⁇ l per well of wash buffer (PBS containing 0.3% Tween 20).
  • wash buffer PBS containing 0.3% Tween 20
  • a preserv ⁇ ative solution containing 10% sucrose, 100 mM phosphate, 150 mM NaCl, and 0.05% NaN 3 (pH 7) were added to each well, and the plates were incubated for 1 hour at room temperature.
  • the preservative solution was then removed by aspiration, and the plates were placed at 37°C, ⁇ 10% humidity, for 18-24 hours.
  • the coated plates were sealed in foil with a dessicant packet and stored at room temperature.
  • N-Dpd standard solutions and serum samples were tested in duplicate.
  • the standard solutions typically consisted of 0, 0.05, 0.1, 0.2, 0.4, 1.0, 3.0, and 9.0 nM N-Dpd in 10 mM PBS containing 0.05% NaN 3 and 10 mg/mL bovine serum albumin.
  • Dpd-alkaline phosphatase conjugate retained in each well was assayed by adding to each well 150 ⁇ L of substrate solution (p-nitrophenyl phosphate, 2 mg/mL in 1 M diethanolamine, pH 10, containing 1 mM MgCl) , incubating at room temperature for one hour, stopping the enzymic reaction by addition of 50 ⁇ L 3 N NaOH, and reading the optical density of the well at 405 nm using a Vmax reader (Molecular Devices Corp.).
  • the Dpd crosslink concentration for each serum sample was determined by comparison with a standard curve constructed with the N-Dpd standard solutions.
  • Example 10 Binding Selectivity of Antibody Reagent N-Pyd, N-Dpd, and pyridinium-peptides (MW>1000) were isolated from urine samples as described above. Aliquots of the pyridinium-peptide fraction were hydrolysed to convert the crosslinks in the fraction to H-Pyd and H-Dpd. The concentrations of Pyd in the N-Pyd and H-Pyd preparations, of Dpd in the N-Dpd and H-Dpd preparations, and of Dpd in the pyridinium- peptide preparation, were determined by HPLC, as in Example l.
  • the percent reactivity of each sample was calculated as a ratio of apparent N-Dpd concentration (measured using the N-Dpd standard curve above) to total Dpd crosslink concentration in the sample determined by HPLC for total H-Dpd (times 100) .
  • the relative reactivity determined for purified N-Dpd was arbitrarily set at 100%, and the reactivities of the other crosslink preparations (and the amino acid mixture) were expressed as a percentage of 100. Results obtained with this assay are shown in Table 2 above.
  • Example 11 Preparation of Anti-Pyridinoline Antiserum
  • New Zealand white rabbits (a total of 59) for immunization were divided into eight groups according to immunization protocol, as indicated below in Table 6.
  • the immunization dose was 200 ⁇ g of Pyd-BSA (Example 3A) , low-hapten Pyd-BSA immunogen (prepared as in Example 3A for Pyd-BSA, but with a lower Pyd:BSA stoichiometry) , or Pyd-KLH (Example 3B) , in 1.0 ml PBS mixed with 1.0 ml of Ribi adjuvant (Ribi ImmunoChemical Research, Inc.).
  • Initial immunization was by subcutaneous injections at multiple sites, and subsequent booster immunizations were given at three week intervals intramuscularly. Antiserum was collected 10 days after each immunization. Table 6
  • each antiserum was tested for Pyd binding affinity using the assay format described in Example 6.
  • binding of anti-Pyd antibodies from the serum to Pyd immobilized on a solid support was detected using an alkaline phosphatase-labeled goat anti-rabbit IgG antibody reagent.
  • Immunized animals were kept if their antisera satisfied the following criteria, defined further in the following paragraph: AA ⁇ 20%, Pyd-peptide ⁇ 10%, titer > 5000, and a 0 to 25 nM Pyd signal separation of > 10% of total modulated signal.
  • Profiles of the most strongly reactive antisera are shown in Table 7 below, as measured using the assay format described in Example 6.
  • the first column indicates the immunization program from which the rabbit antiserum came.
  • the second column indicates the bleeds which were pooled for analysis.
  • the column marked "titer” indicates the dilution of each antiserum necessary to achieve an optical density reading of 1.2 to 1.6 with a Pyd-negative sample (no Pyd present) in the immunoassay.
  • the column marked “AA” shows the cross-reactivity of each antiserum with the amino acid mixture described in Example 7.
  • the column marked "Pyd-pep >1000 MW” shows the cross-reactivity of each antiserum with Pyd-peptides (>1000 MW) .
  • the last column shows the separation between signals for 0 and 25 nM Pyd samples as a fraction of the total modulated signal.
  • rabbits III-3, V-4, and VI-8 showed significant modulation of signal from 0 to 25 nM N-Pyd.
  • the serum with highest activity (VI-8) was selected for use in the N-Pyd assays described herein.
  • Example 12 Preparation of Pyd-Coated Microplates Biotin-labeled ovalbumin and a streptavidin-Pyd conjugate were utilized in the microplate coating. Biotinylation of ovalbumin was carried out by adding 10 mg of biotin-X-2,4-dinitrophenol-X-L-lysine, succinimidyl ester (Molecular Probes) in 400 microliters of dimethylformamide to a 10 ml solution of PBS containing 150 mg of ovalbumin. The mixture was allowed to react for two hours at room temperature, followed by G25 column chromatography. . Spectrophotometric analysis indicated two biotins substituted per mole of ovalbumin.
  • H-Pyd to streptavidin was accomplished by coupling a thiolated streptavidin to H-Pyd via the coupling agent, SMCC.
  • Thiolated streptavidin was prepared by reaction with N- succinimidyl-3-(2-pyridylthio)proprionate (SPDP, Pierce) as follows. To a 0.75 ml solution of 5 mg of streptavidin in PBS was added 21 uL of dimethylformamide containing 260 ug of SPDP. The mixture was allowed to react for one hour at room temperature, and then was dialysed against PBS. The SPDP-labeled streptavidin was reduced by the addition of dithiothreitol to a final concentration of 10 mM. After incubation for one hour at room temperature, the thiolated streptavidin was purified on a G-25 column.
  • H-Pyd-streptavidin a solution containing 180 ug of succinimidyl 4-(N- maleimidomethyl)cyclohexane-1-carboxylate (SMCC, Pierce) in dimethylformamide (4 ul) was added to a solution containing 0.5 mg thiolated streptavidin and 50 ug of H-Pyd in 100 ⁇ l of PBS. The mixture was allowed to react for 3 hours at room temperature and then was dialysed versus PBS. Spectrophotometric analysis of the resultant Pyd-streptavidin indicated between 1 and 2 equivalents of deoxypyridinoline bound per equivalent of streptavidin.
  • SMCC succinimidyl 4-(N- maleimidomethyl)cyclohexane-1-carboxylate
  • Each of the wells in a 96-well ELISA plate were coated with with N-Pyd as follows. To each well was added 150 microliters of biotin-ovalbumin solution at 3.8 ug/ml in PBS, followed by an overnight incubation at 2-8°C. The microplates were washed with PBS and blocked by adding 200 ul of ovalbumin at 1 mg/ml with an overnight incubation at room temperature. The microplates were then twice washed with PBS. The streptavidin-Pyd conjugate is immobilized via the streptavidin mediated binding to biotin.
  • N-Pyd standard solutions and blood serum samples were tested in duplicate.
  • the standard solutions consisted of 0 nM, 0.2 nM, 0.6 nM, 2.0 nM, 6.0 nM, and 24 nM N-Pyd in assay buffer (0.05% NaN3 , 0.05% Tween 20, and 0.1% BSA in 100 mM sodium phosphate containing 150 mM NaCl, pH 7) .
  • Serum samples were filtered through a Centricon-30 filter device (Amicon, Mass.) prior to assay.
  • the optical density readings (405 nm) from duplicate samples were averaged, and the averaged readings from the N-Pyd standards were used to construct a standard curve of OD reading vs. N-Pyd concentration. From this curve, the free N-Pyd crosslink concentration in each serum sample was determined.
  • N-Pyd, N-Dpd, and pyridinium-peptides were isolated from urine samples as described above. Aliquots of the pyridinium preparations were hydrolysed to convert the crosslinks in the fractions to H-Pyd and H-Dpd. The concentrations of Pyd in the N-Pyd and H-Pyd preparations, of Dpd in the N-Dpd and H-Dpd preparations, and of Pyd in the pyridinium- peptide preparation, were determined by HPLC, as in Example l.
  • the percent reactivity of each sample was calculated as a ratio of apparent concentration (measured using the N-Pyd standard curve above) to total Pyd crosslink concentration in the sample determined by HPLC for total H-Pyd (times 100) .
  • the relative reactivity determined for purified N-Pyd was arbitrarily set at 100%, and the reactivities of the other crosslink preparations (and the amino acid mixture) were expressed as a percentage of 100. Results obtained with this assay are shown in Tables 4 and 7 above.

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  • Cell Biology (AREA)
  • Food Science & Technology (AREA)
  • General Physics & Mathematics (AREA)
  • Biotechnology (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Microbiology (AREA)
  • Pathology (AREA)
  • Proteomics, Peptides & Aminoacids (AREA)
  • Hospice & Palliative Care (AREA)
  • Oncology (AREA)
  • Organic Chemistry (AREA)
  • Tropical Medicine & Parasitology (AREA)
  • Biophysics (AREA)
  • Genetics & Genomics (AREA)
  • Preparation Of Compounds By Using Micro-Organisms (AREA)
  • Peptides Or Proteins (AREA)
  • Investigating Or Analysing Biological Materials (AREA)

Abstract

Procédé de détermination des taux de décomposition du collagène osseux chez un sujet humain utile pour détecter la présence de troubles de la résorption osseuse. Cette invention concerne également un procédé de surveillance de l'évolution et/ou réponse du traitement d'une pathologie cancéreuse induisant ou pouvant potentiellement induire l'évolution d'une pathologie métastatique comprenant des altérations de la résorption osseuse.
PCT/US1993/012321 1992-12-17 1993-12-17 Determination de reticulations de pyrimidium serique WO1994014072A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP51453694A JP3448295B2 (ja) 1992-12-17 1993-12-17 血清ピリジニウム架橋物アッセイ
AU58514/94A AU5851494A (en) 1992-12-17 1993-12-17 Serum pyridinium crosslinks assay

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
US99288892A 1992-12-17 1992-12-17
US99293692A 1992-12-17 1992-12-17
US07/992,888 1992-12-17
US07/992,936 1992-12-17
US3760293A 1993-03-26 1993-03-26
US08/037,602 1993-03-26
US14028493A 1993-10-20 1993-10-20
US08/140,284 1993-10-20

Publications (1)

Publication Number Publication Date
WO1994014072A1 true WO1994014072A1 (fr) 1994-06-23

Family

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Family Applications (1)

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PCT/US1993/012321 WO1994014072A1 (fr) 1992-12-17 1993-12-17 Determination de reticulations de pyrimidium serique

Country Status (4)

Country Link
JP (1) JP3448295B2 (fr)
AU (1) AU5851494A (fr)
CA (1) CA2151234A1 (fr)
WO (1) WO1994014072A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996027134A1 (fr) * 1995-03-01 1996-09-06 Metra Biosystems, Inc. Dosage par transpiration destine a evaluer la resorption osseuse
US5756361A (en) * 1992-12-17 1998-05-26 Metra Biosystems, Inc. Screening method for periodontal disease
US5972623A (en) * 1997-07-31 1999-10-26 Metra Biosystems, Inc. Collagen-peptide assay method
WO2000040974A1 (fr) * 1999-01-07 2000-07-13 Quidel Corporation Dosage de liaisons reticulees de pyridinium

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991008478A2 (fr) * 1989-12-01 1991-06-13 Washington Research Foundation Procede de detection de la degradation de collagene in vivo

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991008478A2 (fr) * 1989-12-01 1991-06-13 Washington Research Foundation Procede de detection de la degradation de collagene in vivo

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
ALLAN LIPTON ET AL.: "Increased Urinary Excretion of Pyridinium Cross-Links in Cancer Patients", CLINICAL CHEMISTRY., vol. 39, no. 4, April 1993 (1993-04-01), WINSTON US, pages 614 - 618 *
C.R. PATERSON, S.P. ROBINS ET AL.: "Pyridinium Crosslinks as markers of bone resorption in patients with breast cancer", BRITISH JOURNAL OF CANCER, vol. 64, no. 5, November 1991 (1991-11-01), LONDON, GB, pages 884 - 886 *
N.A.T. HAMDY ET AL.: "Urinary collagen crosslink excretion: a better index of bone resorption than hydroxyproline in Paget's disease of bone?", BONE AND MINERAL, vol. 22, no. 1, June 1993 (1993-06-01), SHANNON, IE, pages 1 - 8 *
SIMON P. ROBINS ET AL.: "Measurement of the cross linking compound, pyridinoline, in urine as an index of collagen degradation in joint disease", ANNALS OF RHEUMATIC DISEASES, vol. 45, no. 12, December 1986 (1986-12-01), LONDON, GB *
SIMON P. ROBINS: "An enzyme-linked immunoassay for the collagen cross-link pyridinoline", THE BIOCHEMICAL JOURNAL, vol. 207, no. 3, 1 December 1982 (1982-12-01), LONDON,GB, pages 617 - 620 *
SIMON P. ROBINS: "Cross-linking of collagen", THE BIOCHEMICAL JOURNAL, vol. 215, no. 1, 1 October 1983 (1983-10-01), LONDON, GB, pages 167 - 173 *
V.T. KUNG ET AL.: "A Monoclonal Immunoassay for Collagen Crosslinks", CALCIFIED TISSUE INTERNATIONAL, vol. 52, no. SUP1, June 1993 (1993-06-01), HEIDELBERG, DE, pages S92 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5756361A (en) * 1992-12-17 1998-05-26 Metra Biosystems, Inc. Screening method for periodontal disease
WO1996027134A1 (fr) * 1995-03-01 1996-09-06 Metra Biosystems, Inc. Dosage par transpiration destine a evaluer la resorption osseuse
US5661039A (en) * 1995-03-01 1997-08-26 Metra Biosystems, Inc. Perspiration assay for bone resorption
US5972623A (en) * 1997-07-31 1999-10-26 Metra Biosystems, Inc. Collagen-peptide assay method
WO2000040974A1 (fr) * 1999-01-07 2000-07-13 Quidel Corporation Dosage de liaisons reticulees de pyridinium
US6716593B1 (en) 1999-01-07 2004-04-06 Quidel Corporation Pyridinium crosslinks assay

Also Published As

Publication number Publication date
JPH08507140A (ja) 1996-07-30
JP3448295B2 (ja) 2003-09-22
AU5851494A (en) 1994-07-04
CA2151234A1 (fr) 1994-06-23

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