%0 Journal Article %A Meier-Ewert, H. %A Gibbs, A. J. %A Dimmock, N. J. %T Studies on Antigenic Variations of the Haemagglutinin and Neuraminidase of Swine Influenza Virus Isolates %D 1970 %J Journal of General Virology, %V 6 %N 3 %P 409-419 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-6-3-409 %I Microbiology Society, %X Summary The neuraminidases and haemagglutinins of 20 isolates of swine influenza virus collected between 1930 and 1967 were compared in neuraminidase-inhibition and haemagglutination-inhibition serological tests. All the isolates were serologically related to a greater or lesser extent in tests with either antigen. The antigenicity of the two antigens varied independently in different isolates. There was a slight, but statistically significant, drift in the antigenicity of both antigens during the period in which the isolates were collected. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-6-3-409