The macrophage is an essential component of the host defense against intracellular pathogens including MAC. Especially alveolar macrophages act as a first line defense in the lungs against MAC infection. Some cytokines were reported to activate mouse peritoneal macrophages and human monocyte-derived macrophages to inhibit growth or kill MAC. But we could find only one report describing the effect of cytokines on anti-MAC activities of human alveolar macrophages (PAM). Thus, we investigated the effect of several cytokines on anti-MAC activities of PAM. PAM were recovered from 12 healthy subjects by bronchoalveolar lavage and cells were cultured in RPMI 1640 with 10% heat-inactivated human AB serum. After 2 hours incubation nonadherent cells were discarded by vigorous washing to from monolayers of PAM (2 x 10(5) PAM in each 11-mm diameter tissue culture dish). Then we added 2 x 10(6) viable MAC bacteria (31F093T) and each cytokine to the wells simultaneously. We prepared the well without cytokines as control. After 96 hours incubation, PAM were disrupted by sonication, then all bacteria that had located inside and outside of the cells were plated onto 7H10 agar. The results are reported as mean colony forming units per each well. We had determined the optimal dose of each cytokine to prime PAM for enhanced O2- release and we used that optimal dose in this experiment. PAM with TNF-alpha pretreatment, and PAM with IFN-gamma pretreatment could release increased amount of O2- significantly, compared with control. PAM with IL-2 pretreatment and PAM with GM-CSF pretreatment also released somewhat increased amount of O2-.(ABSTRACT TRUNCATED AT 250 WORDS)