ABSTRACT
A modification of serological tests, the antihemagglutinin exhaustion test, was developed for the study of capacity of different fractions of the antigenic preparations of tick-borne encephalitis and western equine encephalomyelitis viruses to react with antibody. The test is simple to perform, highly sensitive and specific which permits within a very short time to examine the antigenic activity of practically all, including non-hemagglutinating, virus fractions obtained by gel chromatography and ultracentrifugation. Significant functional heterogeneity of virus particles in interaction with antibody was established. Non-hemagglutinating virions were capable of binding antihemagglutinins. The intensity of interaction with antibody of the most active virus fractions in the HI and CF tests was considerably higher than that of nonfractionated preparations.
