Effect of mutation in immunodominant neutralization epitopes on the antigenicity of rotavirus SA-11

Exposure of rotavirus SA-11 to polyclonal neutralizing antibody from hyperimmunized guinea-pigs permitted selection of variants which were poorly neutralized by antisera against the parental virus. In one-way cross-neutralization experiments, at least 22 of 24 plaque-purified variants could be classified as belonging to a serotype different from that of the parent. Most antisera generated against the variants, however, readily neutralized the parental virus. This indicates that immunodominant neutralization epitopes in the parent differed from those in the variants. Changes in immunodominant epitopes caused the serotypic relationships between the variants and other strains of rotavirus to differ from those of the parental SA-11. The serotypic relatedness of human strain P (human serotype 3) was reduced while, in contrast to results found with the parental SA-11, several of the antisera against the variants recognized the bovine rotavirus NCDV as the same serotype. Causes for these changes are discussed.