Interferon Synthesis in X-Irradiated Animals III. The High Radiosensitivity of Myxovirus-Induced Circulating Interferon Production

Abstract

The effect of X-irradiation on circulating interferon induction was examined in C3H/He mice, 4 days after total-body exposure to 125, 250, 500, or 1000 R. Nine viruses were tested as inducer: Newcastle disease, influenza A, Sendai, mumps, Sindbis, Semliki Forest, vesicular stomatitis, encephalomyocarditis, and vaccinia. Interferon induction by the four myxoviruses was very radiosensitive, exposure to 125 R being sufficient to reduce serum interferon levels to values ranging between 4 and 28% of levels in control animals. In contrast, interferon induction by either encephalomyocarditis or vaccinia viruses was very radioresistant, and even after 1000 R significant amounts of circulating interferon were produced. Circulating interferon induction by vesicular stomatitis, Sindbis and Semliki Forest was of intermediate radiosensitivity. The high radiosensitivty of myxovirus-induced circulating interferon production suggests an involvement of lymphocytes in circulating interferon induction by these viruses.