ABSTRACT
Objective To compare the adjuvanticity of type-A,B and C CpG-ODN in mice.Methods Three types of CpG-ODN were identified through in vitro stimulation of murine splenocytes with various CpG-ODN.BALB/c mice were immunized with HBsAg,together with different types of CpG-ODN,and antigen-specific IgG.IgG1 and IgG2a titers were measured 4 weeks later by indirect ELISA.Resuits Compared with the control group.all 3 types of CpG-ODN enhanced humoral immune response to HBsAg.However,type-B and C CpG-ODN induced much higher levels of antigen-specific IgG and IgG2a than type A CpG-ODN.Type-C CpG-ODN induced a similar TH 1-biased immune response as type-B CpG-ODN,revealed by decreased IsG1 to IgG2a ratio.In contrast,although type-A CpG-ODN increased IgG titers,it did not switch the balance between TH1 and TH2 immune responses.Conclusion All 3 types of CpG-ODN can enhance the humoral immune response to vaccines,but their aaiuvanticity could be mediated through different mechanisms.