An improved enzyme-linked immunosorbent assay of anti-collagen antibodies in human serum.

An improved enzyme-linked immunosorbent assay (ELISA) for the determination of anti-collagen antibodies in human serum has been developed. The method is based on the use of serum samples diluted to 1/50 with heat-inactivated normal rabbit serum adjusted to pH 8.0 with solid Tris (0.05 M), NaCl (0.15 M) and 2 M HCl. The use of normal rabbit serum minimizes non-specific adsorption of immunoglobulin G onto the plastic surface of microtiter plate. The applicability of the method for the quantitation of anti-collagen antibodies in human serum is demonstrated with 290 specimens of sera from normal controls (194) and patients with rheumatoid arthritis (96).