Antigenicity, immunogenicity and passive protection induced by immunization of mice with baculovirus-expressed VP7 protein from rhesus rotavirus

The major neutralization antigen VP7 of rhesus rotavirus (RRV) was expressed in a baculovirus recombinant system. The expressed VP7 showed the same molecular mass as native VP7, and was recognized by hyperimmune sera as well as neutralizing and non-neutralizing monoclonal antibodies (MAbs) raised against RRV. Intraperitoneal administration of the expressed VP7 in mice elicited the production of serum antibodies which were able to immunoprecipitate VP7 from RRV-infected cell lysates and to neutralize the virus in vitro. Sera from immunized mice competed for binding to RRV in an ELISA with both neutralizing and non-neutralizing MAbs specific for VP7. Using a passive protection model of rotavirus disease, vaccination of mice with the recombinant VP7 induced partial protection from infection. These results suggest that the baculovirus-expressed VP7 may be useful in priming a protective immune response to rotavirus infection.