Serum opsonin, bacteria, and polymorphonuclear leukocyte interactions in subacute bacterial endocarditis

Abstract

The effect of anti-γ-globulin factors on 7S γ-globulin opsonins from patients with subacute bacterial endocarditis has been examined with a quantitative in vitro phagocytosis system. Human anti-γ-globulin factors from patients with subacute bacterial endocarditis and rheumatoid arthritis inhibited the opsonic action of 7S γ-globulin specifically bound to bacteria. A similar antiopsonic effect was obtained with rabbit antiserum to human γG globulin. The antiopsonic effect of anti-γ-globulin factors did not correlate with their ability to potentiate agglutination of bacteria by 7S antibody. Competition was demonstrated between the antiopsonic effect of anti-γ-globulin factors and the phagocytosis-promoting action of heat-labile serum factors containing hemolytically active complement.