Antigenic Variation of Rhinovirus Type 22 1

Summary Seventeen of eighteen type 22 rhinoviruses isolated in this laboratory were shown to be antigenic variants of the prototype strain (127-CV22). The variant viruses were neutralized poorly or not at all by immune serum to the prototype strain. However, immune serum prepared to one of the variant viruses (Chase) neutralized both the prototype and homologous strains to similar titer and also neutralized all of the other isolates. The neutralizing reactivity of the Chase virus immune serum for the prototype and homologous strains was found to be essentially unaltered by multiple absorptions with human liver powder, a procedure capable of removing cytoxic factors or nonspecific inhibitors found in certain rhinovirus antisera. The Chase virus thus appears to represent a “prime strain” of rhinovirus type 22. The authors acknowledge the excellent technical assistance of Mrs. Dana Gallo and Mrs. Florence Lester.