[Enhancement of mouse immune response by recombinant adenovirus co-expressing VP1-2A of foot-and-mouth disease virus and porcine IFN-α].

Objective: To construct the recombinant adenovirus co-expressing foot-and-mouth disease virus (FMDV) viral structural protein1-2A (VP1-2A) and porcine interferon-α (poIFN-α), and study its impact on mouse adaptive immune responses.

Methods: FMDV VP1-2A genes and porcine IFN-α (poIFN-α) genes were successively cloned into pAdeno Vator-CMV5-IRES-GFP, and then both pAdeno Vator-CMV5-IRES-GFP with VP1-2A-poIFN-α and pAdeno Vator ΔE1/E3 were co-transfected into E.coli BJ5183 competent cells. The homologous recombinant plasmid rAd5VP1-2A-poIFN-α was screened and linearized by Pac I to expose the encapsidation signal and then transfected into HEK293A cells by Lipofectamine(TM)2000. The positive recombinant viruses were named rAd5VP1-2A-poIFN-α. The BALB/c mice were immunized by the recombinant adenovirus rAd5VP1-2A-poIFN-α or rAd5VP1 (adenoviral vectors solely expressing FMDV VP1) or blank adenovirus as control (Ad virus). The FMDV VP1-specific IgG, IgG1, IgG2a and cytokines IL-4, IFN-γ were determined by the ELISA, and the index of peripheral blood lymphocyte proliferation was detected by MTT assay.

Results: The recombinant adenovirus co-expressing FMDV VP1-2A and porcine IFN-α (rAd5VP1-2A-poIFN-α) was successfully constructed. ELISA and MTT assay showed that compared with rAd5VP1 group, rAd5VP1-2A-poIFN-α could enhance the secretion of FMDV VP1-specific IgG, IgG1 and IgG2a, promote the secretion of IL-4 and IFN-γ, and increase the index of peripheral blood lymphocyte proliferation.

Conclusion: The rAd5VP1-2A-poIFN-α could significantly improve the mouse adaptive immune responses.