Monoreassortant Rotaviruses of Multiple G Types Are Differentially Neutralized by Sera From Infants Vaccinated With ROTARIX and RotaTeq.

Background: Rotavirus is a leading cause of pediatric diarrheal mortality. The rotavirus outer capsid consists of VP7 and VP4 proteins, which, respectively, determine viral G and P type and are primary targets of neutralizing antibodies.

Methods: To elucidate VP7-specific neutralizing antibody responses, we engineered monoreassortant rotaviruses each containing a human VP7 segment from a sequenced clinical specimen or a vaccine strain in an identical genetic background. We quantified replication and neutralization of engineered viruses using sera from infants vaccinated with monovalent ROTARIX or multivalent RotaTeq vaccines.

Results: Immunization with RotaTeq induced broader neutralizing antibody responses than ROTARIX. Inclusion of a single dose of RotaTeq in the schedule enhanced G-type neutralization breadth of vaccinated infant sera. Cell type-specific differences in infectivity, replication, and neutralization were detected for some monoreassortant viruses.

Conclusions: These findings suggest that rotavirus VP7, independent of VP4, can contribute to cell tropism and the breadth of vaccine-elicited neutralizing antibody responses.