Distinctive Characteristics of Crude Interferon from Virus-infected Guinea-pig Embryo Fibroblasts

Crude interferon preparations from primary guinea-pig embryo cells infected with vesicular stomatitis virus strain T1026R1 were shown to be more sensitive to heat (37 °C), pH 2.0, and SDS than crude mouse interferon. Since the proportion of antiviral activity lost after each treatment was nearly the same, the existence of a single fraction of antiviral activity sensitive to all three treatments was suggested. Support for this possibility was given by the finding that subjecting this guinea-pig interferon to any one of the treatments rendered it insensitive to the effects of the other two. We have previously shown that guinea-pig embryo fibroblasts (GPE cells) infected with several different viruses were capable of producing more antiviral activity (interferon) than had been previously reported by other laboratories (Kaplan et al., 1962; Friedman et al., 1962; Lackovic et al., 1979; Warfel & Stewart, 1980; Sonnenfeld, 1981; Christofinis, 1980), but that much of this activity was too labile to be detected by conventional means (Winship et al., 1983). It was found that virus type, multiplicity of infection, and cell age are important factors in determining the total yield of these substances (Winship et al., 1983). In this communication, we describe several basic biological and physical characteristics o