Adjuvant effect of a polysaccharide PCP-I from Poria cocos on HBsAg antigen in mice / 国际药学研究杂志

ABSTRACT

Objection To investigate the adjuvant activity of a polysaccharide PCP-Ion immune response in HBsAg immunized mice. Methods Crude polysaccharides from Poria cocos (PCP) were obtained successively by extracting with water at 60°C, ethanol precipitating and dialyzing. A polysaccharide PCP-Iwas separated from PCP by DEAE- cellulose and Sephadex G- 100 columns. The sugar content was determined by phenol-sulfuric acid method, monosaccharide compositions were analyzed with capillary electrophoresis, and molecular mass of PCP-I was determined with gel filtration chromatography. BALB/c mice were immunized intramuscularly twice with HBsAg (2 μg/mouse) plus PCP-I (50 or 200 μg/mouse). The serum IgG and its isotypes antibody titers of immunized mice were analyzed by ELISA at 14, 30, 45, 60 and 90 d after second immunization. The proliferation activities of spleen T and B lymphocytes were determined with MTT method. The populations of CD3+, CD19+, CD4+ and CD8+ lymphocytes were determined by flow cytometry. The phagocytosis function of macrophages was evaluated with neutral red method in vitro. Results A new polysaccharide (PCP-I) was separated from sclerotium of P. cocos. PCP-I had a relative molecular mass of 3.0×104 and was composed of fucose, mannose, glucose and galactose in molar ration of 1.00 1.81 0.27 7.27, respectively. Pharmacological data demonstrated that PCP-I significantly increased antigen-specific antibody levels of IgG1,IgM,IgG2a,IgG2b and IgG3 in immunized mice and generated robust and durable immunity compared to mice immunized with HBsAg-alum after second immunization for 14 ~ 90 d. PCP-I also improved proliferation of splenocytes,raised the ration of CD3+/CD19+ cells and decreased the ratios of CD4+/CD8+ T lymphocytes. PCP-I stimulated phagocytosis function of peritoneal macrophages in immunized mice. Conclusion These results suggested that PCP-I enhanced humoral and cellular immunity in HBsAg-immunized mice,and its adjuvant activity was stronger than alum.