Abstract
Formation of prominent multinucleated giant cells (MGC) was observed in monolayers of a clonal line of BHK-21 cells (BHK-21-528) when infected with Japanese encephalitis virus (JEV). MGC were first observed 3 to 4 days after infection and cytopathic changes proceeded thereafter. Formation of MGC is a typical cytopathic change in this clonal cell line. Virus titer in 50%, tissue culture infective dose (TCID50) equaled that in 50% MGC-forming dose. Virus titer in TCID60 was approximate to plaque-forming units (PFU) in the same host cells. An ability of JEV to form MGC was maintained at least for six serial passages in BHK-21-528. It was inactivated by heating at 56 C for 3 min. All JEV strains, except an attenuated live vaccine strain, induced formation of MGC in BHK-21-528 cells. Red blood cells of several animal species were not adsorbed to MGC induced by JEV. The MGC-forming ability of JEV was specifically neutralized by anti-JEV serum. By fluorescence antibody technique, the MGC were specifically stained by anti-JEV antibody conjugated with fluorescein isothiocyanate. Immunization of animals with lysates of the MGC resulted in production of antibodies against JEV, but no antibody against other viruses which have been reported to induce MGC formation. From these evidences, it was concluded that JEV induced formation of MGC in BHK-21-528.
