Altered responsiveness of murine lymphoid cells treated with cryptococcal capsular polysaccharide.

Abstract

AbstractPurified capsular polysaccharide derived from Cryptococcal neoformans was studied in terms of effects on immune responsiveness of mouse spleen cells to sheep red blood cells in vivo and in vitro. Injection of mice with small doses of polysaccharide enhanced the primary IgM antibody response, whereas larger doses suppressed the response. The polysaccharide also modulated the in vitro immune response of normal mouse spleen cells immunized with sheep erythrocytes. The blastogenic responsiveness of murine spleen cells to Con A and pokeweed mitogens were markedly suppressed by the highest dose of cryptococcal polysaccharide tested, i.e., 100 μg/ml. These results demonstrate that the purified polysaccharides of an opportunistic fungus can significantly modulate both antibody and mitogenic responses in the murine system, and suggest that this material may have a wider role in affecting host immune response mechanisms.