The Improvement of Immune Effect of Recombinant Human Beta-Defensin 2 on Hepatitis B Vaccine in Mice

Immunization with hepatitis B vaccine is an effective measure for prevention and control of hepatitis B Virus (HBV) infection. Although lots of efforts to improve the effect of hepatitis B vaccine have been made, the function of human beta defensin 2 (hBD2) on hepatitis B vaccine keeps unclear. In this article, we report that hBD2 not only promoted the activation and maturation of immature dendritic cells (iDCs) by increasing MHC II and CD86 expression, but it also significantly upregulated the mRNA level of IL-6 and IL-12B in mouse bone marrow-derived dendritic cells. The serum concentrations of IFN-γ in mice stimulated with 300 ng hBD2 increased from 25.21 to 42.04 pg/mL, with a time extension from 4 to 12 h post-injection. During the process of three times immunization (1, 14, 28 days) with 3 μg hepatitis B vaccine combined with or without 300 ng hBD2 with a 2 week interval in BALB/c mice, the antibody against HBsAg (HBsAb) concentration in serum at every time point of observation in the combined group was statistically higher than the hepatitis B vaccine group. The serum concentration of IgG2a subclass HBsAb on the 14th day post last injection in the combined group was significantly higher than the hepatitis B vaccine group. Further, the splenic cells from the mice treated with both hBD2 and hepatitis B vaccine possessed a greater ability to produce a surface antigen of hepatitis B virus (HBsAg) specific IFN-γ than those treated with hepatitis B vaccine alone. The percentages of CD3+/CD4+ T cells and CD3+/CD8+ T lymphocytes in spleens from the mice treated with 300 ng hBD2 were statistically higher than the phosphate buffered saline group. These data suggest that hBD2 improves iDC maturation and the immune efficiency of hepatitis B vaccine in BALB/c mice.