Glycyrrhiza uralensis Fisch L. crude polysaccharides enhance mouse immunity and immune responses induced by HPV-DNA vaccine

Abstract

Objective To investigate the effects of Glycyrrhiza uralensis Fisch L. crude polysaccharides (GUCP) as an adjuvant on the immunity of mice and the immune responses induced by human papilloma virus (HPV)-DNA vaccine. Methods ICR mice were injected with different concentrations of GUCP by different ways to detect the influences of GUCP on body weight, organ indexes and the numbers of immune cells in spleen. C57BL/6 mice were co-immunized with HPV-DNA vaccine and GUCP to detect the adjuvant efficacy on antigen-specific cellular and humoral immune responses. Results GUCP in all injected groups had no side effect on mouse body weight and liver, heart, lung and kidney indexes, but intraperitoneal injection of GUCP significantly increased spleen and thymus indexes and the numbers of B cells, CD4+ T cells, macrophages and dendritic cells in spleen. Subcutaneous injection of GUCP significantly increased the numbers of B cells and macrophages in spleen and intragastric administration significantly increased the numbers of CD4+ and CD8+ T cells in spleen. Furthermore, GUCP as an adjuvant enhanced the antigen-specific CD4+ and CD8+ T cell responses and the levels of IgG, IgG1 and IgG2a induced by HPV-DNA vaccine at a certain degree. Conclusion GUCP enhanced the immunity of mice and the antigen-specific cellular and humoral immune responses induced by HPV-DNA vaccine. These results suggested that GUCP might be used as an adjuvant for DNA vaccine. Key words: Glycyrrhiza uralensis Fisch L.; Crude polysaccharides; Immunity; DNA vaccine; Immune response