Immunosuppression in murine malaria. I. Response to type III pneumococcal polysaccharide.

Acute Plasmodium yoelii yoelii and chronic Plasmodium berghei malaria infections of CBA mice were accompanied by a reduced capacity to give an antibody response to type III pneumococcal polysaccharide (SIII). The depression of response initiated by acute malaria persisted for several weeks after recovery from clinical infection. During chronic infection, and at the peak of acute parasitaemia, virtually no response to SIII was detected. A substance which crossreacted serologically with SIII was found in blood cells of infected mice. The results suggest that antigen-specific, as well as non-specific, factors may contribute to the depression of the response to this antigen.