[Differentiation of matrix proteins of influenza A viruses using enzyme immunoassay].

Matrix protein is known as a type-specific structural protein of influenza viruses. An attempt has been made to find out whether or not strain-specific components could be detected from matrix protein, in addition to its type-specific antigen determinants. The technique of enzyme immune assay was chosen as the optional method to differentiate between matrix proteins of various influenza-A viruses. Antigen titration was undertaken of several matrix proteins, using two specific anti-matrix-protein sera in each case. Information regarding serological relationships between the tested matrix proteins of various influenza-A viruses was obtained from a quotient between the titres of one antigen, on the one hand, and the two anti-matrix-protein sera used in titration, on the other. Two matrix protein sub-types were established in the context of the influenza-A viruses tested. Sub-type M1 was attributable to older strains (A/PR/8 and A/FM/1), whereas the matrix protein of sub-type M2 was found to be present in more recent strains (A/Hongkong and A/Port Chalmers).