Incorporation of Escherichia coli heat-labile enterotoxin B subunit into rabies virus particles enhances its immunogenicity in mice and dogs

Although inactivated vaccines against rabies have the advantage of high safety,effective protection against rabies virus(RABV)infection often requires multiple,high-dose immunization.Incorporating a molecular adjuvant into the viral particles has been found to be a useful strategy to promote the immune effectiveness of inactivated vaccines.In this study,we constructed a recombinant virus,rCVS11-LTB,which chimerically expresses a molecular adjuvant heat-labile enterotoxin B subunit(LTB)protein on the surface of the RABV particles.Immunogenicity in vivo was found to be promoted by rCVS11-LTB through the activation of dendritic cells(DCs).Our results demonstrated that inactivated rCVS11-LTB was able to induce higher levels of virusneutralizing antibodies(VNAs)in both mice and dogs than the parent virus rCVS11,to enhance the cellular immune response and T cell immune memory in mice,and was also able to provide 100%protection in mice from lethal doses of rabies virus,indicating its potential as a safe and effective inactivated rabies vaccine candidate.