A human-derived protein SBP (HBsAg-binding protein) can bind to hepatitis B virus surface antigen (HBsAg) and enhance the immune response to hepatitis B virus (HBV) vaccine
ABSTRACT A high titer of antibody to HBsAg (Hepatitis B virus surface antigen) (anti-HBs) is a requisite for the prevention of HB (Hepatitis B), and adjuvants generally play a great role in eliciting special anti-HBs to HB vaccine. However, adjuvants still need to be improved because of their shortages such as unremarkable efficacy, undesirable side effect or poor security. In this study, we used HBsAg separated from HB patient sera to screen a human liver cDNA expression library, and found a novel HBsAg-binding protein (SBP), which is located at the human chromosome 14q32.33 and is similar to human IgG heavy chain in structure. Western blot demonstrated that SBP existed in both healthy human sera and HB patient sera. Furthermore, SBP could bind to HBsAg by its N-terminal domain. Notably, we confirmed that SBP could promote dendritic cells (DC) to phagocytize HBsAg more effectively and enhance the immunogenicity of HB vaccine, when SBP was mixed proportionally with HBsAg and the resulting mixture was infused into mice. These results suggest that SBP could be developed into a safe and promising adjuvant of HB vaccine.
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ABSTRACT: The development of effective vaccines against the rabies virus could prevent infection with this fatal virus. However, the current rabies vaccine fails to provide a full range of protection because of its limited ability to elicit a cellular immune response and the requirement for repeat vaccination. Monophosphoryl lipid A (MPLA) is well known as a potent adjuvant to enhance immune responses against virus infection. Here we investigated the efficacy of MPLA as an adjuvant to improve the humoral and cellular immune responses to the rabies vaccine in BALB/c mice. Supplementation of the rabies vaccine with MPLA significantly accelerated the production of specific antibodies by 10 days compared to the original vaccines. Furthermore, MPLA promoted the induction of stronger cellular immune responses by the rabies vaccine, including the production of IL-4, IFN-γ and the activation of CD4(+)/CD8(+) T cells, than those elicited without MPLA. Collectively, our findings indicated that MPLA enhances humoral and cellular immunity and is a promising adjuvant for the development of more effective rabies vaccines.Immunobiology 05/2013; 218(12). DOI:10.1016/j.imbio.2013.05.006 · 3.18 Impact Factor