Enzymatic alteration of C1q, the collagen-like subcomponent of the first component of complement, leads to cross-reactivity with type II collagen

• Published in: FEBS letters 1988-02, Vol.228 (2), p.332-336
• Main Authors: Heinz, Hans-Peter, Brackertz, Dieter, Loos, Michael
• Format: Article
• Language: English
• Subjects: Animals; Antibodies - immunology; Antibodies, Monoclonal - immunology; Antigens - immunology; Arthritis, Rheumatoid - enzymology; Arthritis, Rheumatoid - immunology; Autoantibodies - immunology; Biological and medical sciences; C1q; Collagen; Collagen - immunology; Collagenase; Complement; Complement Activating Enzymes - immunology; Complement Activating Enzymes - metabolism; Complement C1 - immunology; Complement C1 - metabolism; Complement C1q; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Granulocytes - enzymology; Humans; Microbial Collagenase - metabolism; Molecular immunology; Osteoarthritis - immunology; Rheumatoid arthritis; Sheep; Spondylitis, Ankylosing - immunology; Synovial Fluid - enzymology; Synovial Fluid - immunology; Synovitis - immunology
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(88)80026-7

Native serum C1q, the collagenous-like subcomponent of the first component of complement, is not recognized by polyclonal anti-collagen type II antibodies. However, when purified C1q was subjected to limited proteolysis by collagenase it showed antigenic cross-reactivity with collagen type II. The same cross-reactivity was observed with hemolytically active C1q in synovial fluids of patients with rheumatoid arthritis (RA), whereas C1q from synovial fluids of patients with osteoarthritis (OA), villo-nodular synovitis and ankylosing spondylitis was not recognized by this antibody. However, incubation of synovial fluid C1q of OA patients with synovial fluid leucocytes from RA patients led to an alteration of OA-C1q which was now recognized by the anti-collagen type II antibody.