SUMMARY

Interferon-treated L cells exhibit a specific enhanced susceptibility o the cyto-toxic and interferon inducing activities of double-stranded RNAs such as poly(I). poly(C). These activities remained closely linked through widely varying assay conditions, involving, for example, different time and dosage schedules of poly(I). poly(C), suggesting that there is at least one common step in the mechanisms leading to interferon formation and toxicity in interferon-primed cells exposed to poly(I).poly(C). However, some procedures uch as addition of metabolic inhibitors (actinomycin D, cyctoheximide) and repeated administration ofpoly(I). poly(C) suppressed the interferon inducing capacity of poly(I), poly(C) without a concomitant decrease of toxicity. Other procedures such as brief treatment of the cells with interferon or DEAE-dextran permitted full expression of the interferon inducing activity of poly(I), poly(C) without any sign of toxicity. The latter results suggest hat the mechanisms underlying interferon production and toxicity of poly(I), poly(C) in interferon-treated L cells diverge from a certain point onward