System for Measuring and Designating Antigenic Components of Influenza Viruses with Analyses of Recently Isolated Strains

Abstract

A method for designating antigenic components of influenza A, B and C viruses consisting of formulae derived from the results of agglutination-inhibition tests with chicken antisera prepared against a selected group of prototype strains was presented and discussed. Studies to determine the antigenic patterns of some recently isolated influenza A viruses by the agglutination-inhibition technic revealed that the A prime strains isolated in 1950-51 formed a remarkably homogeneous group resembling the 1950 FW-1-50 (Cuppett) agent. The Benson virus, which was an exception, was indistinguishable from the 1947 FM1 strain. The results of the antigenic analyses of some WS-and PR8-like viruses isolated since 1947 (during which time the A prime form of influenza A was predominant) were also included and their significance discussed.