Aflatoxin inhibition of viral interferon induction.

The inhibitory effect of four basic aflatoxins on interferon induction by influenza virus in LLC-MK2 cell monolayers follows a structure-activity series with decreasing potency in the order aflatoxin B1 greater than G1 greater than B2 approximately G2. Of the four aflatoxins, B1 was the most deleterious to both cell growth and the viability of cells in confluent cultures. The fact that higher levels of influenza virus growth were attained in aflatoxin-treated cells than in normal cell monolayers was related to increased aflatoxin concentration in association with decreased interferon production. The ability of interferon to confer cellular resistance against viral infection, however, was not altered by aflatoxin. The inhibitory activity of aflatoxin on interferon production may be a factor contributing to impairment of host resistance to viral infections.