Antigenic Relationships of the West Nile, Japanese B Encephalitis, and St. Louis Encephalitis Viruses

[摘要] The immunologic relationships of the West Nile, St. Louis encephalitis, and Japanese B encephalitis viruses were investigated by subcutaneous cross-neutralization test in 3-day-old mice and by cross-immunity tests.In addition to specific neutralization of virus by homologous immune serum, cross-reactions were observed to occur in the following directions. West Nile immune serum neutralized the St. Louis virus, but not the Japanese; St. Louis immune serum neutralized the West Nile and Japanese viruses; and the Japanese immune serum neutralized the West Nile and St. Louis viruses. These findings, added to the recent report of Casals and the original observations of Smithburn, indicate that these viruses, while immunologic entities, are all related one to another. The amount of antigen shared in common, however, appears to be very small, judging by the difficulty in eliciting the cross-reactions, and by the relatively small amount of crossing present when demonstrable.Present attempts to confirm the serologic findings by cross-immunity tests were negative, as has been the experience of others.The occurrence of cross-reactions introduces a complicating factor in the diagnosis of infections due to these viruses, and it is suggested that such reactions may be eliminated by appropriate adjustment of the specificity of the versatile extraneural neutralization test in young mice.

[学科分类] 生物科学（综合）