In vitro suppressive effect of aflatoxin B-1 on murine peritoneal macrophage functions

We examined the immunosuppressive effects of aflatoxin B-1 (AFB(1)), a toxi c compound produced by the Aspergillus flavus, on murine peritoneal macroph ages after in vitro pre-exposure. When thioglycollate-elicited macrophages pre-exposed to AFB(1) were stimulated with lipopolysaccharide (LPS), antitu mor activity induced by LPS was suppressed by 10 and 50 mu M AFB(1). In add ition, the production of reactive intermediates including nitric oxide (NO) , superoxide anion and hydrogen peroxide which have been known to be implic ated in macrophage-mediated cytotoxicity, was decreased by AFB(1) pretreatm ent in a dose-dependent manner. We also determined whether the macrophage-m ediated cytokine production was altered by AFB(1) in vitro pretreatment. AF B(1) markedly inhibited TNF-alpha, interleukin-l (IL-I) and IL-6 production by LPS-stimulated macrophages. Taken together, these data indicate that AF B(1) inhibits the killing ability of murine macrophages, decreases various secretory molecules in those cells and the macrophages would be one of many systems affected by AFB(1). (C) 1999 Elsevier Science Ireland Ltd. All rig hts reserved.