Abstract
Currently, commercial porcine rotavirus vaccines remain varied limitations. The objective of this study is to develop an alternative porcine rotavirus subunit vaccine candidate by parenteral administration, which enables to elicit robust immune responses against most prevalence porcine rotavirus strains. The bacterially-expressed porcine rotavirus P[6]- or P[7]-specific truncated VP8* (aa 64-223) recombinant protein with or without a universal tetanus toxoid CD4(+) T cell epitope P2 was generated. All the recombinant subunit proteins Delta VP8*s or P2-Delta VP8*s were of high solubility and high yields. The immunogenicity of each purified Delta VP8* and P2-Delta VP8* was evaluated in mice (10 mu g/dose) or guinea pigs (20 mu g/dose) immunized IM with 600 mu g aluminum hydroxide three times at 2-week interval. The introduction of P2T cell epitope to P[7]-Delta VP8* elicited significantly higher IgG titer in mice than its absence. Comparatively, P2 epitope slightly enhanced the immunogenicity of P[6]-Delta VP8*. P2-P[7]Delta VP8* elicited high titer of neutralizing antibody against heterotypic P[7]-specific rotaviruses with varied G type combination. Our data indicated that two subunit vaccines could be plausible bivalent rotavirus vaccine candidate to provide antigenic coverage of porcine rotavirus strains of global or regional importance. (C) 2015 Elsevier Ltd. All rights reserved.