Immunologic Studies of Japanese Encephalitis Virus in Japan

[摘要] Maternal antibodies reacting with JE virus were found in newly hatched domestic chicks and wild birds near Tokyo, Japan. The neutralization test detected these antibodies more frequently than the hemagglutination-inhibition test; in wild birds of the family Ardeidae , an average of only 25% of birds with maternal neutralizing antibody during the first 15 days of life were positive at 1:10 plasma dilution by HI test. Neutralizing antibody disappeared below detectable levels (log neutralization index less than 1.0) in half the ardeids by 5–15 days after hatching and in all birds by 21–30 days. Maternal neutralizing antibody in chicks prevented viremia upon challenge with JE virus, but did not affect viremia from WEE virus. In ardeids, maternal antibody apparently prevented infection by JE virus in one bird but not in another, suggesting that some ardeid hens have specific antibody to JE virus and others have nonspecific “antibody”. This observation is compatible with summer infection of some ardeids with JE virus in Japan and winter infection of others with immunologically-related Group B arthropod-borne viruses in southeast Asia. Nevertheless after maternal antibody becomes undetectable, ardeids and chicks are fully susceptible to JE virus.

[学科分类] 生物科学（综合）