Inhibition of interferon action by chinoform

Chinoform, iodochlorhydrozyquin, was found to suppress the antiviral action of interferon. Chick embryo fibroblast cells treated with the mixture of interferon and chinoform were more sensitive to Sindbis virus infection than cells treated with interferon alone. No evidence for a direct inactivation of interferon molecule by chinoform was obtained. Treatment with chinoform of cells previously exposed to interferon also removed a cellular antiviral state induced by interferon. Chinoform suppressed intracellular ribonucleic acid (RNA) and protein syntheses. It is suggested that the inhibitory effect of chinoform on the action of interferon is due to a suppression of continued production of antiviral proteins.