Anticryptococcal activity of NK cell-enriched peripheral blood lymphocytes from human immunodeficiency virus-infected subjects: responses to interleukin-2, interferon-gamma, and interleukin-12.

Anticryptococcal activity of highly purified NK cells from patients with either early asymptomatic or late-stage human immunodeficiency virus (HIV) infection proved to be markedly impaired; activity was reproducibly restored to normal levels by in vitro addition of exogenous interleukin-12 (IL-12). For these highly purified NK cells, responses to IL-2 and interferon-gamma (IFN-gamma) among HIV-infected patients were variable, with only 2 of 8 exhibiting significant responses to IL-2 or IFN-gamma. In contrast, IL-2 and IFN-gamma consistently enhanced anticryptococcal activity of mixed lymphocyte populations, cells that more closely approximate the network likely to be operational in vivo.