The relationship between penetration and uncoating of poliovirus in HeLa cells

To investigate the cellular site of poliovirus uncoating, the interaction of adsorbed photosensitized virus with HeLa cells was followed by three measurable transitions: (a) to nonneutralizability, (b) to photoresistance, (c) to nonrecoverability from lysed cells. At 37° the rates of these transitions were similar. At lower temperatures the rates decreased, but the rate of the neutralization transition decreased less than the rates of the other two. At 25° virus penetrated cells so that it could no longer be neutralized, yet it was still photosensitive and could be recovered in infectious condition when the cells were lysed. If virus was allowed to penetrate at 25° and the temperature was then raised to 37° the transition to photoresistance and to nonrecoverability occurred. The capability of HeLa cells to uncoat poliovirus does riot require an induction period. Through the use of inhibitors it was shown that the capability to uncoat is independent of cellular protein synthesis. These observations indicate that the uncoating system is a normal component of HeLa cells.