Suppression of interferon synthesis by the pesticide carbaryl as a mechanism for enhancement of goldfish virus-2 replication.

Interferon production was demonstrated by the goldfish-derived CAR cell line in response to infection by goldfish virus-2. Supernatants of infected cultures provided antiviral protection to CAR cells and another cell line derived from goldfish, ABIII. The protective factor retained activity after ultracentrifugation, dialysis, freezing and thawing, acid treatment (pH 2), or heating to 56 degrees C but was sensitive to trypsin. Supernatants of infected cultures did not affect adsorption of virus. Previous studies have shown that replication of goldfish virus type 2 is enhanced by pretreatment of cultures with subcytotoxic concentrations of carbaryl. In the present study, pesticide-treated cultures were found to synthesize reduced levels of interferon.