Vibrio vulnificus VvhA induces Th1 and Tfh cells to proliferate against Vibrio vulnificus in a mouse model of infection.

AIM: To characterize the roles of VvhA in host's acquired immune response to Vibrio vulnificus infection.

MATERIALS & METHODS: The recombinant VvhA fusion protein was used to immunize mice and the anti-VvhA polyclonal antibody was produced in vivo for prophylactic and therapeutic efficacy assay. The roles of VvhA in T helper (Th) cells differentiation were analyzed by vvhA-deleted mutant during the early phase of infection, while the ratio of Th2 and T follicular helper (Tfh) cells were examined in VvhA immunization.

RESULTS: Anti-VvhA antibody exhibited neutralization activity against V. vulnificus. Wild-type strain induced higher level of Th1 cells than the mutant, and the concentrations of IgG2a and IFN-γ were increased during the early phase of infection. The spontaneous development of Tfh was observed in immunized model, and the serum IL-21 was increased.

CONCLUSION: V. vulnificus VvhA elicited cellular and humoral immune responses by Th1 and Tfh cells to provide protection against VvhA.