Rheumatoid factors reacting with autologous native gamma-G-globulin and joint fluid gamma-G aggregates.

Abstract

Inflammatory joint fluids from patients with definite or classical rheumatoid arthritis (RA), selected because they precipitated strongly with rheumatoid factors (RF), were examined by sucrose density gradient ultracentrifugation for sedimentation of γG-globulin (γG) and behaviour of RF activity. All contained some γG that sedimented to the γM globulin (γM) zone at pH 7·4; at pH 3·6, γG disappeared from the γM zone. With four joint fluids, no RF activity was detected by cells sensitized with anti-CD Ripley at pH 7·4, but RF activity appeared in the γM zone at pH 3·6. This demonstration of inhibition of RF activity by autologous γG aggregates depended upon the relative amount of RF and γG aggregates in the joint fluid. Two joint fluids which contained γG aggregates and high titre RF activity precipitated with γM RF isolated in high concentration from the corresponding sera.