Evaluation of Adjuvanticity and Protective Efficacy of Recombinant ORFV B2L Protein Adjuvanted FMD Vaccine in Guinea Pigs

The present study evaluates the adjuvant effect of rec -B2L protein of orf virus and widely used oil adjuvant with purified inactivated FMDV 146S trivalent antigens (O, A and Asia 1) in guinea pig model. Rec -B2L protein expressed in prokaryotic expression system was co-administered intradermally with FMDV trivalent antigens. The serum antibody titre, CMI response and protective efficacy against FMDV-type ‘O’ virulent virus challenge were assessed. The antibody titres of oil adjuvant group were found highest. However, rec -B2L group showed better antibody titre than the control group. The levels of IgG 1 were found to be constant throughout the experiment except some fluctuations noticed on 14th and 28th dpv against serotype A and Asia1. Rec- B2L group showed higher levels of IgG 2 against serotype A on 14th and 28th dpv than FMDV trivalent antigens alone. Further, the adjuvant effect of rec- B2L protein was also reflected by enhanced levels of IFN-γ, TNF-β on 28th dpv; IL-15, IL-10 on 7 dpv in the immunized serum samples. The oil adjuvant group and rec -B2L group showed a centum protection following challenge on 28th dpv. These preliminary findings indicate the adjuvant effect of rec -B2L protein.