SENSITIVITY TO, AND PRODUCTION OF INTERFERON BY THREE VARIANTS OF MENGO VIRUS

The sensitivity to interferon, and interferon-producing capacities of three plaque variants of Mengo virus have been studied. It has been shown that the Mengo variants, which differ greatly in their pathogenicity for mice, induce the production of very little interferon in L cells or primary mouse embryo fibroblasts, and that all are about half as sensitive to inhibition by interferon as is vesicular stomatitis virus. Serum and brain interferon titers closely parallel serum and brain virus titers following the intraperitoneal injection of mice with 106 plaque-forming units (PFU) of each variant, but there is little difference in the amounts of interferon produced in lethal and in non-lethal infections. It is concluded that interferon production in vivo is unlikely to be more than a minor defense mechanism against infection with Mengo virus.