Immunomodulative effects of aflatoxins and selenium on human peripheral blood lymphocytes.

We investigated the antagonist immunomodulative properties of aflatoxin B1 and selenium on human peripheral blood lymphocytes by 2 colorimetric in vitro cytotoxicity assays, the neutral red uptake and the thiazolyl blue tetrazolium bromide assay. Immunotoxic properties of these substances were determined by a (3H)-thymidine DNA incorporation assay on phytohemagglutinin (PHA) stimulated and non-stimulated lymphocytes. Aflatoxin B1 and selenium, when studied separately, had an immunosuppressive effect on PHA stimulated and non-stimulated human peripheral blood lymphocytes. When they were studied together, they had an antagonistic effect on this immunological parameter.