Studies on the cellular nature of Candida albicans-induced suppression

Animals treated with formalinized Candida albicans manifest depressed cellular immune activity. Splenocytes from mice treated with as little as 14 micrograms of this material exhibited significantly reduced responses to the T cell-dependent mitogens phytohemagglutinin and concanavalin A. On the other hand, the B lymphocyte-dependent response to bacterial lipopolysaccharide was normal in these cultures. Splenocytes from treated mice were capable of actively suppressing the T cell- (but not B cell-) dependent proliferative response of normal cells. Analysis of splenocytes from Candida-treated mice showed that the suppressor cell is adherent to glass wool, is not adherent to Sephadex G-10, does not phagocytize carbonyl iron, is not susceptible to treatment with anti-Thy-1 plus C, but does bind specifically to anti-immunoglobulin- (anti-Ig) coated dishes. The adherence to the anti-Ig-coated dishes was not due to the simple attachment of Fc receptor-bearing lymphocytes, because dishes coated with the F(ab')2 fragment of rabbit antimouse IgG bound the suppressor cell. These results suggest that the active Candida-induced suppressor cell is composed, at least in part, of surface Ig-bearing B lymphocytes.