Passive transfer of collagen arthritis: heterogeneity of anti-collagen IgG.

Using a combination of affinity chromatography procedures, anticollagen IgG was fractionated into three distinct populations. One population reacted only to conformational determinants, another population reacted only to structural determinants, and the third population reacted to both conformation and structural determinants. When these populations were tested for their arthritogenicity, only those fractions that reacted to conformational and to conformational and structural determinants were active in inducing clinical arthritis. Immunofluorescence analysis of the hind paw of recipient rats indicated that antibodies directed only to conformational and to both conformational and structural determinants bound to articular cartilage and activated the complement system. Antibodies directed strictly to structural determinants did not bind to articular cartilage and were nonarthritogenic.