NATURAL-KILLER-CELLS DO NOT PLAY A DOMINANT ROLE IN CD4-ALBICANS-INFECTED MICE( SUBSET DIFFERENTIATION IN CANDIDA)

The effects of in vivo administration of monoclonal antibodies against NK-1.1-bearing cells on the early production of gamma interferon (IFN -gamma) in vitro and development of Th1-associated immunity were studi ed in mice infected with a live vaccine strain of Candida albicans. At 1 and 4 days postinfection, natural killer (NK) cell-enriched fractio ns from the spleens of antibody-treated mice displayed a dramatic redu ction in 5E6+ lymphocytes and negligible anti-YAC-1 cytotoxic activity in vitro. Nevertheless, the frequency of IFN-gamma-producing cells in those fractions was reduced by less than half, on average, by anti-NK -1.1 treatment in vivo. In addition, the antibody-treated and infected mice demonstrated unchanged T helper cell responses, as measured by y east-specific footpad reactions, resistance to reinfection, occurrence of antibodies of different isotypes, and production in vitro of inter leukin-2 (IL-2), IFN-gamma, IL-4, and IL-10 by CD4+ cells. Therefore, although NK cells may contribute to early IFN-gamma production in Cand ida-vaccinated mice, these cells apparently do not play a dominant rol e in the qualitative development of yeast-specific T helper responses.