Effect of medium of lowered NaCl concentration on virus release and protein synthesis in cells infected with reticuloendotheliosis virus.

When cultures producing reticuloendotheliosis virus were incubated for 24 h in medium of lowered NaCl concentration, virus production was inhibited. The extent of inhibition increased as the salt concentration of the medium was decreased. The inhibition was rapidly reversed by replacement of low-salt medium with normal medium. During the first hour after the inhibited cultures were returned to normal medium, virus was released at an accelerated rate, making the total amount of virus released by inhibited and control cultures the same. After 1 h in normal medium, the rate of virus production in the previously inhibited cultures was the same as in the control cultures. Incubation of infected cells in low-salt medium resulted in a 60% decrease in the overall rate of protein synthesis. Although returning the cells to normal medium rapidly reversed the inhibition of virus production, it did not rapidly increase the rate of protein synthesis. These results suggest that host cell-directed protein synthesis is preferentially inhibited by the low-ionic-strength medium, whereas that required for virus production continues.