Hepatitis A ViruscDNA andItsRNA Transcripts AreInfectious inCellCulture

A full-length cDNAcopy ofan attenuated, cell culture-adapted hepatitis A virus (HAVHM-175/7 MK-5) genome was constructed inthePstIsite ofplasmid vector pBR322. Transfection ofmonkeykidney cells with thisplasmid failed toinduce theproduction ofhepatitis A virus (HAV).TheHAV cDNA was excised from pBR322andinserted, without theoligo(dG) oligo(dC) tails, into an RNA transcription vector toyield plasmid pHAV/7.Transfection ofmonkeykidney cells withpHAV/7DNA induced HAV infection. Transfection with RNA transcripts produced invitro frompHAV/7yielded about10-fold more HAV thandidtransfection with pHAV/7DNA.Marmosets inoculated withtransfection-derived virus developed anti-HAV antibodies andhad liver enzyme patterns thatclosely resembled theliver enzyme patterns seeninanimals inoculated withvirus fromacomparable level ofcellculture passage.Infectious RNA transcripts fromHAV cDNAshould beuseful forstudying themolecular basis ofcell culture adaptation andattenuation aswell asforstudying specific viral functions.