[The hepatitis A virus isolated and adapted in human diploid fibroblast cells (KMB17)].

Three hepatitis A virus (HAV) strains (L8, H32 and H52) were isolated from stool specimens of hepatitis A patients during an epidemic in 1988 in Shanghai and were adapted to grow in human diploid fibroblast cell strain (KMB17). The strains were serially carried through 10 passages in KMB17. The infectious titrations of these virus strains cultured for 28 days at the 10th passage were high up to 7.0-7.75 log TCID50/ml. The maximum virus yields occured in the 28th day after infection. Immune electronic microscopic studies revealed that the viral particles were 27-30 nm in diameter. The strains were neutralized by specific anti-HAV serum. Special fluorescent stained particles were observed clearly in the infected cellular plasma by direct IF. The above data suggest that the three strains are HAV and may be useful for further study.