A malaria 'mitogen'-induced depressed immune response to meningococcal polysaccharide vaccine in BALB/c mice.

Uninfected female BALB/c mice were given a 4-daily intraperitoneal injection, of supernatants obtained from 24-h cultures of Plasmodium berghei infected and control mouse red blood cells, for 20 days. Each mouse was subsequently injected subcutaneously with 10 mg meningococcal (groups A and C combined) polysaccharide vaccine. Mean meningococcal haemagglutinating antibody titres obtained in mice pretreated with control supernatants were consistently higher, than those obtained in mice pretreated with supernatants from malaria-infected red blood cell cultures, over a period of 14 days. The results suggest that a malaria 'mitogen' may be involved in the pathogenesis of the immunosuppression characteristic of this infection.