STRAIN OF HEPATITIS A VIRUS CAUSING CYTOPATHIC EFFECTS ISOLATED IN A549 CELL LINE

A strain (named BJ-1) of hepatitis A virus (HAV) causing cytopathic effects (CPE) has been isolated in A549 cell cultures from a fecal specimen of an infant with hepatitis A. Hepatitis A antigen (HAAg) w3s detectable in about 50To of the cells by immunofluo- rescence (IF) assay. The viral antigenicity was spe- cifically identified by monoclonal anti-HAV and chim- panzee reference antiserum to HAV (NIH). HAV particles in crystal arraDgement were observed in cell cytoplasm by electron microscopy in ultrathin sec tions. The particles appeared both "empty" and "full". It was observed that many 27-30 nm virtts particles were aggregated by convalescent human he- patitis A sera and chimpanzee HAV antisera observ- ed by immune electron microscopic (IEM) ex- amination. BJ-1 HAAg could be detected on day 34 after inoculation at the initial passage. The virus titers increased and the virus replication cycle short- ened with serial passages. The highest TCID 50 was 10-5/0.1 ml and the shortest replication cycle 2-3 days. IF kit consisting of BJ-1 HAV infected A549 coverslip culture and sheep fluorescence antibody to human IgM were made to detect anti-HAV IgM. Comparing the BJ-t IF with the Abbott EIA HAVAB- M kit. the coincidence rate was 98.4% (246/250).