Selenylation modification can enhance immune-enhancing activity of Chuanminshen violaceum polysaccharide

Chuanminshen violaceum polysaccharides (CVPS) were extracted, purified and selenizingly modified. The modification has been achieved by using the HNO₃- Na₂SeO₃ method, and selenizing Chuanminshen violaceum polysaccharides (sCVPS) were evaluated for their physicochemical properties and their potential as adjuvant to modulate cellular and humoral immune responses to hepatitis B subunit vaccine in a mouse model. Our results demonstrated that sCVPS significantly promoted splenocytes proliferation and the production of IL-4 and IFN-γ in vitro. In vivo experiments showed that sCVPS significantly increased the rHBsAg-specific IgG level, IgG subclass (IgG1, IgG2a, and IgG2b) antibody titers, T cells proliferation, levels of IL-4, IL-2, and IFN-γ in CD4 ⁺T cells and the level of IFN-γ in CD8⁺T cells. Furthermore, sCVPS increased the activity of natural killer cells and cytotoxic T lymphocytes, thus increasing both cellular and humoral immune responses in vivo. The present data suggest that selenylation of CVPS can significantly improve their immune-enhancing activity both in vitro and in vivo, thus representing a powerful adjuvant for vaccine design.