title: Nature of the effector cells responsible for antibody-dependent cell-mediated killing of Cryptococcus neoformans.
abstract: Studies were performed to identify the types of human peripheral blood leukocytes capable of killing Cryptococcus neoformans in the presence of anticryptococcal antibody in vitro. A total of 24.1 +/- 2.7% (mean +/- standard error of the mean of four experiments) of the original cryptococcal inoculum survived in a mixed mononuclear, cell preparation (approximately 30% monocytes) after 4 h of incubation at 37 degrees C with rabbit anticryptococcal antibody. When phagocytic cells were removed, there was 36.4 +/- 4.6% survival in six experiments, compared with 52.8% survival in the presence of purified granulocytes (mean of two experiments) and 96.9 +/- 1% survival in the presence of purified T cells. There was never any significant killing in control mixtures that contained leukocytes with normal rabbit serum nor in those that contained anticryptococcal antibody without effector leukocytes. Significant antibody-dependent fungicidal activity was seen with ratios of effector to target cells as low as 6.25:1. These observations indicate that multiple types of peripheral blood leukocytes, excluding T cells, are capable of antibody-dependent fungicidal activity.
mesh_terms: D000908:Antibodies, Fungal; D003454:Cryptococcus / Q000276:immunology*; D003455:Cryptococcus neoformans / Q000276:immunology*; D003601:Cytotoxicity Tests, Immunologic; D006098:Granulocytes / Q000276:immunology; D006801:Humans; D007962:Leukocytes / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology; D009000:Monocytes / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000908:Antibodies, Fungal