Primary isolation of a brazilian strai9n of hepatitis A virus (HAF-203) and growth in a primate cell line (FRhK-4)

RESUMO

Although hepatitis A is endemic in Brazil, this is the first report describing the isolation of a Brazilian strain of hepatitis A virus (HAV). Fecal specimens obtained from patients in the acute phase of hepatitis A were iunoculated into fetal Rhesus kidney cell cultures (FRhK-4). Only one inoculum, denoted HAF-203, could be propagated serially. Both cell lysates and tissue culture fluids of infected cells were used as inocula and evaluated for viral antigen and RNA content by enzyme immunoassay and cDNA-RNA hybridization, respectively. Cell lysates gave better yields when used as viral inocula. After three passages, viral RNA and antigen were detected in cell lysates 4 and 14 days post-infection, respectively. Using tissue culture fluid as inoculum, the incubation period was decreased from 49 to 7 days after 4 serial passages, reflecting the adaptation of HAF-203 to growth in FRhK-4 cells. FRhK-4 cells can now be used for HAV antigen production for diagnostic assays and molecular characterization