Relation of HVJ (Sendai virus) production to cell growth phase in persistently infected mouse 3T3 cells.

Using 3T3 mouse fibroblasts persistently infected with temperature-sensitive HVJ (3T3-HVJ pi), the relationship between production of HVJ and cell growth was investigated. In these cells the highest virus release into the culture media occurred from 24 to 48 hours after seeding. The release gradually decreased as the cultures approached confluency, at which time it was reduced below 1-2 per cent of that on day 2 in parallel with the decrease of both cellular DNA and RNA synthesis rates. Comparative examination in growing and resting HVJ carrier 3T3 cells showed that amounts of nucleocapsids and rate of viral structural protein synthesis in the latter phase was reduced to 4-5 per cent of those in the former phase. In addition, viral replication and transcription rates in the resting phase were found to be suppressed to 8-9 per cent of levels detected in the growing phase. These results suggest that the reduced virus production in the resting HVJ carrier cells may be mainly due to the suppression of viral RNA synthesis.