Summary
A technique is described for the preparation of hemagglutinins for Semliki Forest and Bunyam wera viruses from infected suckling mouse serum. The titer of hemagglutinin appeared to be related to the infective titer of the serum. No hemagglutinin could be demonstrated for either virus in suckling mouse brain despite a high infective virus titer.
Specificity tests with homologous and heterologous immune mouse sera demonstrated the relative specificity of the Semliki antigen and the absolute specificity of the Bunyamwera in HI tests.
HI tests were carried out with selected human sera previously studied by neutralization test with the two viruses. Correlation between the two types of test was obtained with 73% of the sera for Semliki and 87% of the sera for Bunyamwera.
It is suggested that the antigens are of value for preliminary survey purposes and perhaps for diagnosis of recent infection. The technique of antigen production should be useful for the identification of these viruses as well as being applicable to other viruses.