Antineuraminidase antibody response to vaccination of chickens with intact virus and different submit preparations of the influenza virus strains A/Sing/1/57 (H2N2), A/Hong Kong/1/68 (H3N2) and A/Port Chalmers/1/73 (H3N2).

The antineuraminidase (AN) antibody response to vaccination of chickens with intact virus and different subunit preparations of the influenza virus strains A/Sing/1/57 (H2N2), A/Hong Kong/1/68 (H3N2) and A/Pt. Chalmers/1/73 (H3N2) was tested comparatively. Using a photometric method capable of analysing mixtures of AN antibodies against antigenically different N2 neuraminidases, it was concluded that vaccination with subunits produced by treatment with bromelain and Sarkosyl can yield AN antibody response against heterologous neuraminidase. By contrast, vaccination with intact and ether-treated virus gave AN antibody response against homologous neuraminidases. The conclusion was reached that the NA's of the strains A/Sing/1/57 and A/Pt. Chalmers/1/73 share antigenic determinants and that the NA of the strain A/Hong Kong/1/68 shares antigenic determinants with that of the strains A/Sing/1/57 and A/Pt. Chalmers/1/73.