Antigenic Memory in Man in Response to Sequential Infections with Influenza A Viruses

Abstract

The immunologic relations among six strains [A/Swine/15/31, AO/PR/8/34, AlIFM/1I47, A2/Japan/305/57, A2/Kumamoto/2/65, A2/Aichi/2/68 (Hong Kong), and B/Lee/40] of influenza virus that infect man were studied. The results indicate that these viruses can be divided into two groups, the early-appearing, linked group consisting of A/Swine/15/31, AO/PR/8/34, and AlIFM/1I47, and the late-appearing, linked group that includes all A2 and Hong Kong strains. The phenomenon known as the “doctrine of original antigenic sin” existed within each group but not between the two groups.