Biochemical and immunologic comparison of virus-like particles for a rotavirus subunit vaccine.

Abstract A parenterally administered rotavirus vaccine composed of virus-like particles (VLPs) is being evaluated for human use. VLPs composed of bovine VP6 and simian VP7 (SA11, G3) proteins (6/7–VLPs) or of bovine VP2, bovine VP6, and simian VP7 (SA11, G3) proteins (2/6/7–VLPs) were synthesized and purified from Sf9 insect cells co-infected with recombinant baculoviruses. 6/7– and 2/6/7–VLP administered parenterally (i.m.) in mice had comparable immunogenicity, but the 2/6/7–VLPs were more homogeneous and stable. The inclusion of the VP2 capsid contributed to particle formation and stability. The adjuvant QS-21 significantly enhanced the immunogenicity of 2/6/7–VLPs over A10H or saline alone. Equivalent serum neutralizing antibody responses were induced over the range of 1–15  μ g/dose of 2/6/7–VLPs administered with the range of 5–20  μ g/dose of QS-21. The immunogenicity of 2/6/7–VLPs and inactivated SA11 virus were comparable. 2/6/7–VLPs are a promising candidate for a parenterally delivered rotavirus subunit vaccine.