Akbar SM, Abe M, Masumoto T, Horiike N, Onji M. Mechanism of action of vaccine therapy in murine hepatitis B virus carriers: vaccine-induced activation of antigen presenting dendritic cells.
J Hepatol 1999;
30:755-64. [PMID:
10365798 DOI:
10.1016/s0168-8278(99)80125-1]
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Abstract
BACKGROUND/AIMS
Vaccine therapy in which vaccine containing hepatitis B surface antigen (HBsAg) is injected has shown therapeutic activity (vaccine therapy) in some human and murine chronic hepatitis B virus (HBV)-carriers. Using HBV-transgenic mice (HBV-Tg), an animal model of the HBV-carrier state, the mechanism underlying the antiviral and immune modulatory capacity of vaccine therapy was studied.
METHODS
Placebo-controlled, double-blind trials of vaccine therapy were conducted in HBV-Tg; some HBV-Tg responded to the therapy, whereas others were non-responders. The titers of HBV-markers, the functions of lymphocytes and antigen presenting dendritic cells were compared between vaccine responders and vaccine non-responders.
RESULTS
The prevaccinated titers of HBsAg, hepatitis B e-antigen (HBeAg), HBV DNA and the responses of lymphocytes to polyclonal mitogens were almost unchanged between responders and non-responders, but the levels of proliferation of HBsAg-specific lymphocytes from non-responders was significantly lower than responders (p<0.05). The capacity of dendritic cells to induce proliferation of T cells and production of antibody to HBsAg (anti-HBs) was significantly higher in responders compared with non-responders (p<0.05). Injection with HBsAg resulted in upregulation of MHC class II and CD86 antigens (p<0.05) on dendritic cells and increased production of IL-12, IL-2 and TNF-alpha in cultures (p<0.05) in vaccine responders but not in non-responders.
CONCLUSIONS
The activation of dendritic cells following injection with vaccine containing HBsAg is the vital factor underlying the therapeutic potentiality of vaccine therapy in HBV carriers.
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