Increase by calcium in production of interferon by L929 cells induced with polyriboinosinate-polyribocytidylate complex.

Calcium chloride (5 to 20 mM) potentiated interferon production induced by rIn:rCn in L929 mouse fibroblasts up to a thousand-fold. Higher concentrations of calcium (20 to 65 mM) mixed with rIn:rCn were associated with increased cytotoxicity and a more acidic medium, but were effective in enhancing interferon production if preparations were adjusted to a uniform pH. Although calcium increased cellular binding of 3H-rCn:rIn, only a partial correlation between binding and interferon production was observed.