Enhanced resistance to coxsackievirus B3-induced myocarditis by intranasal co-immunization of lymphotactin gene encapsulated in chitosan particle.

Coxsackievirus B3 (CVB3) is a gastrointestinal virus causing myocarditis in human and mice. An ideal vaccine for CVB3-myocarditis requires both humoral and cellular immunity at systemic and mucosal compartments. We described here an enhancing strategy for chitosan-pVP1 vaccine by co-immunizing with lymphotactin (LTN) gene, a T cell-attractive-chemokine, encapsulated in chitosan particle to provide more protection against CVB3. Mice were intranasally co-immunized with 4 doses of chitosan-DNA vaccines separately encapsulating VP1 and LTN plasmids by 2 week-intervals and challenged with CVB3 4 weeks after the last immunization. Compared with chitosan-pVP1 alone, co-immunization with chitosan-pLTN significantly increased high-avidity-neutralizing antibody levels in serum and in intestinal mucosa, and promoted systemic and mucosal Th1 and CD8(+)CTL immune responses. Accordingly, enhanced resistance to CVB3-myocarditis was evidenced by reduced myocardial viral load, profound subsidence of myocarditis and increased survival rate. This strategy represents a promising platform for Th1 polarization and protection against mucosal infectious pathogens.