Host-Parasite Relationships Among Group A Streptococci IV. Suppression of Antibody Response by Streptococcal Pyrogenic Exotoxin

摘要: In rabbits, purified streptococcal pyrogenic exotoxin, at 0.002 of the ld50 dose, suppressed antibody response to injected sheep erythrocytes. The was determined by density gradient ultracentrifugal analysis be 19S class. Background serum (50% hemolytic units), as photometrically, correlated well with background antibody-forming spleen cells, hemolytic-plaque technique. exotoxin induced neither positive nor negative changes in levels, but early secondary antigen. A comparison and control experiment showed that gram-negative bacterial endotoxin identical protocol did not induce suppression, well-known adjuvant effect. Because is known inhibit phagocytic function reticuloendothelial system (RES), these data strongly support concept antigen processed cells RES before it evokes a immune response. results also demonstrated may play unique role lowering acquired defense host against infection. If anamnestic temporarily suppressed, then host-parasite balance would upset favor parasite.