Characterization of antiviral activity of spotted souslik (Spermophilus suslicus) interferons

The antiviral activity of three types of spotted souslik interferons So IFN alpha, So IFN beta and So IFN gamma was studied. Fibroblasts of lungs (SL), kidneys (SK) of adult sousliks and skin fibroblasts of foetuses (SE) were equally sensitive to three types of souslik interferons. In contrast to So IFN beta and So IFN gamma, So IFN alpha, exhibited a high (100% of activity in homologous cells) cross species antiviral activity in mouse embryo fibroblasts (MEF) and a low (3% to 10% of the activity) in bovine embryo fibroblasts (BEF) and human embryo fibroblasts (HEF). The development kinetics of antiviral activity not only depended on the interferon type but also on the temperature of incubation. In comparison with So IFN gamma, So IFN alpha and So IFN beta activated earlier the maximal antiviral state. Low incubation temperature (26 degrees C) did not decrease but only delayed the antiviral activity of spotted souslik interferons. Mixed preparations of So IFN gamma with So IFN alpha or So IFN beta exhibited synergistic antiviral activity at physiological (37 degrees C) and low (26 degrees C) temperatures. The development of antiviral activity of So IFN beta as well that of Mu IFN alpha/beta was inhibited by plant lectins which reacted with the cell membrane compounds. All three types of souslik interferons were completely destroyed by trypsin and boiling at 100 degrees C for 1 min. and partially by SDS. Their sensitivity to shaking, beta-mercaptoethanol and mouse antisera against So IFN beta was different in relation to the interferon type.