A Comparison of Proteins among Various Influenza B Virus Strains by One-Dimensional Peptide Mapping

Abstract

The major virus-specific proteins of 5 different isolates of influenza B virus (B/Lee/40, B/Osaka/2/70, B/Yamagata/1/73, B/Aomori/1/76 and B/Yamagata/26/77) were compared by limited proteolysis with Staphylococcus aureus V8 protease and subsequent polyacrylamide gel electrophoresis. The peptide patterns of matrix proteins from all 5 strains were virtually identical. The nucleoproteins and the non-structural (NS1) proteins were also very similar among strains, although the peptides of B/Lee/40 could be distinguished from those of the strains isolated from 1970-1977. The peptides from hemagglutinin (HA) glycoproteins were largely different, even among strains isolated later than 1970. Thus, HA glycoproteins of influenza B virus appear to be more changeable than any of the non-glycosylated proteins. Maps of HA1 were markedly different among strains while maps of HA2 were very similar, which suggests that the structural changes in the HA polypeptide occur preferentially in the HA1 portion. The neuraminidase glycoproteins also showed strain-dependent differences in their mapping patterns.