Pretreatment of L cells with interferon, 10 to 5000 units/ml, did not impair the shutoff of host protein synthesis induced by mengovirus infection. Under conditions which reduced viral protein synthesis to undetectable levels, [35S]methionine incorporation into cell proteins diminished as an exponential function of the multiplicity of infection. However, this phenomenon was transient, since 6 to 8 hr after infection [35S]methionine incorporation began to rise again. At 24 hr, the pattern of newly synthesized cell proteins was similar to that of uninfected cells. © 1979.