Studies on interferon priming: cellular response to viral and nonviral inducers and requirement of protein synthesis

Preexposure of L cells to mouse interferon (priming) and subsequent induction by Newcastle disease virus (NDV) resulted in earlier emergence of interferon and its mRNA by 3–4 hr, and a reduction of the final yield of secreted interferon. The effect of priming was most prominent in L cells stimulated by the addition of poly(I)-poly(C). Only cells that had been primed produced interferon and its mRNA in detectable amounts. When protein synthesis was blocked by the addition of cycloheximide, interferon mRNA was synthesized at the usual time and tended to accumulate in the cytoplasm, providing an estimate of the level of the primed state. By using this system, we were able to show that interferon priming was dependent on cellular protein synthesis.