[Use of the radioimmunoprecipitation method for testing a monospecific serum to an isolated influenza virus hemagglutinin].

Influenza virus hemagglutinin of H3 type was isolated using the proteolytic enzyme bromlaine. The isolated hemagglutinin was shown to have no neuraminidase activity and to contain no admixtures of extraneous proteins. This antigen was used to immunize rabbits and the resulting antiserum had high antibody titers in HI tests. The method of precipitation with the serum of labeled viral proteins showed the serum to be monospecific and to contain antibody to the hemagglutinin alone.