Detection of hepatitis A virus RNA and capsid antigen in individual cells

The replication of hepatitis A virus (HAV) RNA and the production of HAV VP1 protein were examined in cultures of BS-C-1 cells under one-step growth conditions by in situ hybridization and immunofluorescence. Individual cells that had undergone active viral RNA replication were detectable at 24 h post-infection. During subsequent days, increasing numbers of cells began replicating viral RNA, so that by seven days post-infection, all cells had accumulated significant amounts of viral RNA. The results show that the protracted replication cycle of HAV in cultured cells represents a slow recruitment of infected cells into a replication mode, rather than an inherently slow virus reproduction in all cells. With the reagents utilized in this study, nucleic acid hybridization was more sensitive than antigen detection by immunofluorescence or immunoblot analysis.