Antibody to Rheumatoid Synovial Collagenase

An Immunoglobulin G antibody has been isolated from the sera of sheep immunised with purified synovial collagenase obtained from tissue culture medium of rheumatoid synovium. In double diffusion gels and on immunoelectrophoresis the antibody gave a single precipitin line when run against crude and pure synovial enzyme preparations. Selective adsorption of collagenase from concentrated svnovial tissue culture medium eliminated the precipitin reponse. No immunoprecipitation was observed with whole serum or synovial tissue homogenates in double diffusion gels. Incubation of immune immunoglobulin G with synovial collagenase resulted in enzyme inhibition and the formation of immunoprecipitates. Fab′ fragments of the antibody were similarly inhibitory but gave no precipitin response. Non‐specific neutral proteinase activity released bysynovial explants was not inhibited by antibody. Human collagenases derived from gastric mucosa, cornea, and skin were inhibited by the antibody and produced precipitin lines on immunodiffusion showing a reaction of complete identity with the synovial enzyme. Granulocyte collagenase preparations did not react with the antibody. The non‐human collagenases derived from rabbit cornea and dog gingiva were inhibited by the antibody but those from guinea pig skin and the bacterium Clostridium histolyticum were not. None of these collagenases gave precipitin responses on immunodiffusion against the antibody. Synovial enzyme preparations inhibited or denatured by chemical reagents retained their capacity to react with the antibody, whereas inhibition by the serum proteins α 2 ‐macroglobulin or β 1 ‐anticollagenase masked the antigenicity of the enzyme as judged by immunodiffusion experiments. These observations and their relevance to the use of the antibody in elucidating the physiological role of collagenase are discussed.