Collagen is an inert, rigid protein found predominantly in skin, ligaments, bones and teeth. Its most distinctive attribute, essential to a transmitter of mechanical force, is inelasticity. Its fundamental structural unit is tropo-collagen, a molecular rod about 2600Å in length and 15Å in diameter and 300,000 molecular weight. In tendons these macromolecules, grouped as collagen fibrils, run parallel to the axis. In skin the fibrils are interlaced and branched.

In general, IgA and IgG antibodies to collagen in human sera are highly specific to a heterologous type I and/or type II collagen regardless of the disease or crossreactivity to human type II collagen. Interestingly, IgA and IgG antibodies in sera from patients react to the same collagen type and species but appear to be inversely proportional to their levels (i.e. if IgG levels are high, IgA levels will be low and vise versa).

This ELISA kit contains enough material to run two partial plates on two separate occasions (see assay procedure). 1. Type II or type I collagen-coated 8 well strips a) Five, 8-well strips which are uncoated to serve as a control. b) Five, 8-well strips coated with either CII, BII, PII and HII (Human Type II ELISA) or coated with either CI, BI, PI and HI (Human Type I ELISA). c) Four, 8-well strips to be used for reference standards. Two strips are used per run allowing two partial plates to be run two separate occasions. 2. Standard antibody (1.1ml, 16units/ml). 3. Solution A (Blocking buffer, 15ml) 4. Solution B (Sample dilution buffer, 60ml): Use for diluting the standard and sample specimens. 5. Secondary antibody (two vials of biotin-conjugated goat anti-human IgA, lyophilized): Dissolve one vial in 10ml Solution C-1. 6. Solution C-1 (Secondary antibody dilution buffer, 20ml). 7. Peroxidase-conjugated Streptavidin (two vials) Dissolve one vial in 10ml Solution C-2. 8. Solution C-2 (Avidin-Peroxidase dilution buffer, 20ml) 9. Urea-H2O2 plus buffer tablet (two tablets). Dissolve one tablet in 20 ml glass-distilled water. 10. OPD tablet (two tablets): Dissolve one tablet in 20ml Urea-H2O2 buffer prepared in step 9, just before use. 11. Solution D (Stop solution: 7.5ml of 2.5N Sulfuric acid). 12. Solution E (20X Wash buffer, 50ml): Dilute in 1 liter of distilled water.