Shortening by Actinomycin D of Latent Period of Multiplication of Sendai Virus

Abstract

IT has been shown earlier that actinomycin D inhibits the multiplication of influenza viruses without any influence on Newcastle disease virus and Sendai virus multiplication^1,2. It was found that the dynamics of Sendai virus reproduction in actinomycin-treated cultures of chicken fibroblasts and human amniotic cells were changed after the latent period of multiplication was shortened by 2 h (Fig. 1). To clarify this problem an autoradiographic investigation was carried out. Cultures of human amniotic cells infected with Sendai virus (1,000 ID₅₀ per cell) were held at 35° C in Medium 199 or in this medium with 0.5 γ/ml. of actinomycin D. 30 min, 1, 2, 3 and 5 h after onset of incubation samples of cultures were exposed to 1 µc/ml. of tritiated uridine for 30 min, washed in BBS containing excess of unlabelled uridine, fixed in Carnoy solution, covered with emulsion type M and exposed for 1 month. Developed autographs were stained by the Unna method.