Unique Physico-Chemical Properties of Japanese B Encephalitis Virus Hemagglutinin.

Abstract

A specific hemagglutinin recovered from mouse brains infected with the virus of Japanese B encephalitis possessed properties different from all other viral hemagglutinins described thus far. Stable prepns. of high potency were obtained after removal of an inactivating substance by differential centrifugation. The hemagglutinin combined with the receptors on the erythrocytes in a very narrow pH zone, the optimum being between 6.5 and 6.8. Marked enhancement of activity was obtained on dilution in certain buffers of optimum pH. No receptor-destroying enzyme was found either in the infected mouse brains or in cultures of Vibrio cholerae. which destroyed the receptors for influenza virus. ZnSO4 in minute amts. inhibited the hemagglutinin of the Japanese B virus but not that of influenza virus. The inactive zinc-hemagglutinin complex was reactivated by dilution or removal of zinc with H2S. The inhibitor present in normal human serum was removed by shaking with chloroform, while the specific hemagglutination- inhibiting antibody was unaffected, thus providing a simple test for diagnosis of infection with the Japanese B virus. Specific hemagglutinins, with properties different from that of the Japanese B virus, have also been found for the West Nile and Russian Spring-Summer encephalitis viruses.