RT Journal Article SR Electronic(1) A1 Oxford, J. S. A1 Abbo, Hiyam A1 Corcoran, T. A1 Webster, R. G. A1 Smith, A. J. A1 Grilli, E. A. A1 Schild, G. C.YR 1983 T1 Antigenic and Biochemical Analysis of Field Isolates of Influenza B Virus: Evidence for Intra- and Inter-epidemic Variation JF Journal of General Virology, VO 64 IS 11 SP 2367 OP 2377 DO https://doi.org/10.1099/0022-1317-64-11-2367 PB Microbiology Society, SN 1465-2099, AB SUMMARY Detailed antigenic analysis using a panel of monoclonal antibodies was carried out on the haemagglutinin antigen of 53 influenza B viruses isolated from an epidemic in a single school. Thirteen distinguishable antigenic groupings of influenza B viruses could be detected but 26 of the viruses were in two groups (III and IV) which co-existed during the entire epidemic. Antigenically distinguishable influenza B viruses were isolated from an epidemic in a second nearby school. Influenza B viruses isolated from the two schools could be further distinguished by different electrophoretic mobilities of NS1 polypeptides and of genes 1, 2, 3 and 6, whereas viruses from a single school epidemic were very closely related as regards these biochemical characteristics. The findings are consistent with the hypothesis that the outbreak was initiated by a single individual who excreted antigenic mutants of which predominantly two spread and coexisted during the epidemic, although the additional occurrence of random mutations during the evolution of the epidemic cannot be excluded., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-64-11-2367