Mechanism of enhanced viral-myocarditis-prophylactic effect of a novel coxsackievirus B3 mucosal vaccine by LTN adjuvant
Objective To explore the mechanism of lymphotactin(LTN) to exert mucosal adjuvant activity. Methods Complexes of chitosan-pVP1 and chitosan-pLTN were seperately prepared by co-cojugation method, then 50μg(DNA) of each complex was administered intranasally to male BALB/c mice 4times biweekly. Two weeks after the final immunization, mice were challenged with 3LD50 CVB3 to cause viral myocarditis, heart histopathological changes were examined 7 days later. Meanwhile, T cell immune responses, DC percentage and its membrane CD86 expression were monitored in spleen, mesenteric lymph node(MLN) and cervical lymph node(CLN). Results Co-immunizaiton with LTN remarkbly alleviated CVB3-induced cardial injury. This improvement was accompanied with enhanced T cell proliferation and IFN-γ-secreting ability, increased DC frequency and membrane CD86 expression both in spleen and mucosal draining lymph nodes( MLN, CLN). Conclusion LTN exerts its mucosal adjuvant function in augmenting specific T cell immune responses systemically and mucosally via DC enrichment in spleen, MLN and CLN and up-regulation of DC maturation. 
 
Key words: 
Coxsackievirus;  Myocardifs;  Mucosal;  Adjuvant;  Lymphotactin