Stabilization of poliovirus to ³²P decay

Abstract

1971. Stabilization of poliovirus to 32P decay. Can. J. . Suicide experiments with 32P-labeled poliovirus were performed with HeLa S3 cells. The results show that virus-cell complexes become increasingly refractory to 32P decay during the eclipse period, i.e., stabilization to 32P decay occurs during the first 3 h of infection. The data suggest that stabilization is probably due in part to the production of early RNA during the eclipse period because the presence of 32P in the medium during the first 2 h of growth sensitizes infective centers. IntroductionIn 1947 Luria and Latarjet (10) designed an experiment to detect an increase in the number of intracellular phage particles by subjecting phagehost complexes to increasing doses of ultraviolet (uv.) irradiation after infection. Since that time experiments have been performed with uv. light, high-energy X-rays, and internal radiation resulting from the disintegration of incorporated 32P atoms. The data have shown that as intracellular phage development proceeds, a progressive resistance to irradiation occurs (2, 10, 12, 13, 14, 15).To our knowledge no progressive stabilization to 32P decay has been reported with cells infected with an animal virus. Henry and Youngner (7) performed studies with HeLa cells and 32P-labeled poliovirus RNA, but an experiment comparable to that with bacteriophage was not possible because mammalian cells are sensitive to freezing. Therefore modifications were innovated and a temperature of 2C was chosen to arrest viral development. The results failed to show an appreciable increase in resistance to 32P decay during the eclipse period. Experiments with both control and 32P-labeled RNA showed that intracellular viral RNA is unstable at 2C for long periods of time, and the authors suggested that enzymatic degradation might play a part in the sensitivity of intracellular RNA at this temperature.With the use of dimethylsulfoxide (DMSO) a freezing process has been developed which permits poliovirus infected cells to be frozen and