Virus-like particles as a rotavirus subunit vaccine

Rotavirus subunit vaccines are being evaluated for use in humans. The virus-like particles (VLPs) for these vaccines are produced in insect cells coinfected with combinations of baculovirus recombi­ nants expressing bovine RF VP2 and simian SAll VP4, VP6, or VP7 rotavirus proteins. VLPs were administered parenterally to mice and rabbits, and the immunogenicity and protective efficacy of the vaccines were evaluated. Rabbits vaccinated with VP2/4/617 or VP2/617 VLP combinations developed high levels of rotavirus-specific serum antibody and fecal IgG but not fecal IgA. The induction of fecal IgG was associated with total or partial protection from oral challenge with ALA rotavirus. Heterotypic serum and fecal neutralizing antibody was induced in mice vaccinated parenterally with G1 VP2/617 or VP2/4/617 VLPs. VLPs were highly immunogenic when adminis­ tered in QS2l adjuvant, inducing serum neutralizing antibody titers comparable to those induced by SAll virus. VLPs are effective immunogens when administered parenterally and may be an effective subunit vaccine.