Immunological Characteristics of N. Y. Strains of Influenza A Virus From the 1957 Pandemic

Abstract

Six strains of influenza A virus were isolated in New York during the 1957 pandemic. Close antigenic relationship was found among these strains and 2 Far East isolates, and slight antigenic relationship to older prototype strains was also demonstrated. One of the local isolates, RI/5/57, was a very sensitive indicator of the presence of hemagglutination-inhibiting and neutralizing antibodies against the 1957 strains of influenza A virus in human serum. Antibodies to the Rl/5/57 strain were demonstrated in patients of various ages obtained from 1940 to 1957 The sensitivity of the 6 New York strains to non-specific inhibitors of hemagglutination varied from apparent insensitivity in 3 strains to extreme sensitivity in 2.