Antigenic and amino acid sequence analyses of influenza viruses of the H1N1 subtype isolated between 1982 and 1984.

Since the reintroduction of influenza viruses of the H1N1 subtype into the human population in 1977, antigenically distinguishable viruses have been isolated each year from outbreaks of respiratory disease in young people. In this paper the antigenic properties of viruses representative of isolates made in 1982, 1983, and 1984 are compared, and the amino acid sequences of their haemagglutinins are presented. The results provide a complete description of the 1982 and 1983 H1N1 influenza virus haemagglutinins and allow correlation of specific amino acid sequence differences with antigenic differences.