Differential effects of amorphous and crystalline nickel sulfide on murine alpha/beta interferon production

Mouse embryo fibroblast cultures were exposed to various concentrations of amorphous or crystalline NiS (nickel sulfide). After removal of the NiS from the cultures, polyriboinosinic-polyribocytidylic acid was added to induce alpha/beta interferon. Pretreatment of the cultures with crystalline NiS significantly inhibited the production of alpha/beta interferon at relatively noncytotoxic concentrations (i.e., 1 microgram/ml) while amorphous NiS had no significant effect on alpha/beta interferon production at 10 micrograms/ml. Treatment of cells with reduced glutathione did not block the inhibitory effects of crystalline NiS on alpha/beta interferon production, suggesting that these effects are not mediated by a free-radical mechanism.