[Immunological study of Japanese encephalitis virus--serological analysis of strains isolated from Thailand, India, Singapore and Taiwan].

Antigenic comparison of the twenty-two Japanese encephalitis (JE) virus strains, which were isolated from Taiwan, Singapore, Thailand and India between 1963 and 1984, was carried out by the hemagglutination inhibition (HI) test using the 15 monoclonal antibodies characterized by the different reactivities against Nakayama-RFVL, Beijing 1, Kamiyama, Muar or 691004 strain. Of these twenty-two strains, the seventeen strains reacted with the Kamiyama type-specific monoclonal antibody (KAMIMA 6), but anti-Nakayama, anti-Beijing 1 and anti-Muar type-specific antibodies showed no reactivities with any of the strains. This suggested that the currently prevalent JE virus strains in these areas belonged to the Kamiyama serotype. The other five strains (ThCMP 1982, KE083, KE093, 733913 and Ling) did not react with the above four type-specific monoclonal antibodies. Of these five strains, however, all except the KE093 strain showed a similar pattern to the Kamiyama strain on the basis of the HI reactivities against the other eleven antibodies. The KE093 isolated from Thailand in 1983 showed immunologically outstanding different from the other strains. This result showed the immunological diversity of the JE virus.