Rapid completion of the replication cycle of hepatitis A virus subsequent to reversal of guanidine inhibition.

The single-cycle replication kinetics of hepatitis A virus (HAV: HM175 p39) in BS-C-1 cells were examined by RNA hybridization and VP1 immunoblot assays. Viral products accumulated after 4 days of lag phase and reached a plateau by 12 days postinfection. Defective, subgenomic RNAs were not detected by Northern blot analysis of cytoplasmic extracts from infected cells or purified virions. Replication of this HAV strain was markedly inhibited by 2 mM guanidine. Neither the virion itself nor the adsorption process was sensitive to the drug. The inhibitory effect of guanidine was reversible; subsequent to infection in the presence of the drug, a rapid accumulation of viral macromolecules occurred upon removal of guanidine. After release from guanidine inhibition, the replication cycle of HAV could be completed in 3 days. This observation, together with immunofluorescence microscopy data, suggests that the apparent slow growth phenotype of HAV is due to asynchronous replication rather than inherently slow replication. Analysis of virus replication kinetics in synchronized cell cultures indicated that asynchrony in the cell cycle phase was not responsible for the asynchronous replication of HAV.