Induction of IFN-γ cytokine response against hepatitis B surface antigen using melittin

In this study we co-administered melittin along with HBsAg/alum vaccine to investigate if it helps elicitation of Th1/Th2 response.

Hepatitis B virus (HBV) infection is a life-threatening liver infection, which can lead to chronic liver disease. Vigorous T cell responses are stimulated at acute, self-limiting HBV infection, while chronic HBV infection elicits very weak T cell responses. The prevalence of HBV infection has been decreased by the approved vaccination approach using recombinant HBs antigen (HBsAg) and alum i.e. HBV vaccine. Alum, a strong Th2 stimulator, is usually used as adjuvant to increase HBsAg immunogenicity. The present vaccine does not induce protective and/or prophylactic immune response in some groups. Melittin, major active component in the venom of honeybee, induces Th1 development.

Experimental mice were immunized with melittin plus hepatitis B vaccine on day 0 following by two booster doses with the same injections. Lymphocyte proliferation, IFN-γ, and IL-4 level, total antibody and isotyping of IgG1, IgG2a IgG2b, and IgM were measured using ELISA.

Administration of melittin and HBV vaccine had no effect on lymphoproliferation and total antibody responses, but increased IFN-γ response and induced Th1 response.

The present study proposed that administration of melittin along with conventional vaccine shifts T cell responses towards Th1/Th2 dominated with Th1 response. The resultant immune response leads to activation of both cell-mediated and humoral immune responses, both of which required for clearance of HBV infection.