Differences in the electrophoretic migration rates of polypeptides and RNAs of recent isolates of influenza B viruses.

The electrophoretic migration rates of structural and non-structural polypeptides of 38 influenza B viruses isolated in epidemics in 1978-1980 and antigenically closely related to B/Singapore/222/79 virus were compared using high resolution SDS polyacrylamide gels. Thirty of the viruses could be distinguished from the prototype B/Singapore/222/79 virus by electrophoretic migration rate differences in HA, 17 by differences in NP and 27 by differences in mobility of the NS 1 polypeptide. Mobility differences of NP, NS 1 and HA polypeptides was noted in influenza B viruses isolated in the UK in the same year. In addition, electrophoretic mobility of 32P labeled virus RNAs varied for certain UK isolates and indicated heterogeneity in genes 2, 3, 4 and 8 coding for polymerase proteins 2 and 1, nucleoprotein (NP) and non-structural protein (NS 1) respectively.