title: Platycodin D is a potent adjuvant of specific cellular and humoral immune responses against recombinant hepatitis B antigen.
abstract: The ideal adjuvants for hepatitis B vaccines should be capable of eliciting both strong humoral and cellular immune responses, especially Th1 cell and cytotoxic T lymphocyte (CTL) responses. However, Alum used as adjuvants in the hepatitis B vaccines currently commercialized offers limitation in inducing cell-mediated response. Therefore, a less hemolytic saponin platycodin D (PD) from the root of Platycodon grandiflorum has been explored for its potential as an alternative adjuvant. In order to compare the adjuvant activity with Alum, antigen-specific cellular and humoral immune responses were evaluated following immunization with a formulation containing hepatitis B surface antigen (HBsAg) adjuvanted with PD and Alum in mice. The Con A-, LPS-, and HBsAg-induced splenocyte proliferation and the serum HBsAg-specific IgG, IgG1, IgG2a, and IgG2b antibody titers in the HBsAg-immunized mice were significantly enhanced by PD (P<0.05, P<0.01 or P<0.001). PD also significantly promoted the production of Th1 (IL-2 and IFN-gamma) and Th2 (IL-10) cytokines and up-regulated the mRNA expression of Th1 cytokines (IL-2 and IFN-gamma) in splenocytes from the mice immunized with HBsAg (P<0.001). Besides, PD remarkably increased the killing activities of natural killer (NK) cells and CTLs from splenocytes in the HBsAg-immunized mice (P<0.001), which may have important implications for vaccination against hepatitis B virus. The results indicated that PD has strong potential to increase both cellular and humoral immune responses and elicit a balanced Th1/Th2 response against HBsAg, and that PD may be the candidates as adjuvants for use in prophylactic and therapeutic hepatitis B vaccine.
authors.affiliation: Key Laboratory of Animal Epidemic Etiology & Immunological Prevention of Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Kaixuan Road 268, Hangzhou, Zheijiang 310029, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xie
authors.forename: Hong-Xiang
authors.initials: HX
authors.lastname: Sun
authors.forename: Duo
authors.initials: D
authors.lastname: Li
mesh_terms: D000276:Adjuvants, Immunologic / Q000302:isolation & purification / Q000494:pharmacology*; D000534:Alum Compounds / Q000494:pharmacology; D000818:Animals; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D006511:Hepatitis B Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D031238:Platycodon / Q000737:chemistry; D012503:Saponins / Q000302:isolation & purification / Q000494:pharmacology*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014315:Triterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D016207:Cytokines; D006510:Hepatitis B Antibodies; D006511:Hepatitis B Antigens; D017325:Hepatitis B Vaccines; D007074:Immunoglobulin G; D012503:Saponins; D014315:Triterpenes; D014614:Vaccines, Synthetic; C041524:aluminum sulfate; C108953:platycodin D