Influence of cobra venom (CoF) and pneumococcal S III capsular polysaccharide on immunologic humoral response and visceral distribution of antigens.

The immunologic response to sheep erythrocytes was compared in mice treated with Cobra venom (CoF) and with pneumococcal capsular antigen S III. Suppression of the immunologic response in both cases was attributed to the ability of both tested substances to activate the third component of complement. CoF and S III both changed the organ localization of labeled antigens capable of activating the complement system. No evidence for an alternative pathway by which S III could activate the complement system was found. On the basis of the literature data and experimental findings, the properties of CoF and S III were compared in the light of their ability to suppress the immunologic response.