A candidate multi-epitopes vaccine against encephalomyocarditis virus confers protection in mice

Encephalomyocarditis virus (EMCV) is a widely distributed RNA virus that causes diseases in animals with zoonotic potential. Infection with this pathogen in animals, especially in pigs, can lead to encephalitis, myocarditis, and reproductive disorders. The virus causes a febrile disease in humans and is thus not only a potential threat to the swine industry but also to human health and society. However, there is still no commercial EMCV vaccine available, making the development of a novel and effective EMCV vaccine a priority. Here, we developed an EMCV multi-epitopes candidate vaccine, MIgH-EMCV-Ⅱ^2D2, by directly concatenating universal T-cell epitope sequences with B-cell epitopes of EMCV structural proteins VP1, VP2, and VP3 in a tandem manner. Vaccination of MIgH-EMCV-Ⅱ^2D2 formulated with adjuvants FCA / FIA induces neutralizing antibodies against EMCV, and also elicits a robust Th1-dominant cellular immune response in vivo against EMCV. Furthermore, our MIgH-EMCV-Ⅱ^2D2 vaccine showed stronger protection in mice in the prime-boost regimen than the single-dose regimen. The MIgH-EMCV-Ⅱ^2D2 vaccination conferred complete protection against live EMCV PV21 strain challenge with a 100 % survival rate. These results indicate that the MIgH-EMCV-Ⅱ^2D2 vaccine is a promising, safe, and effective vaccine candidate and could potentially be used for the prevention and control of EMCV.