The role of IL-12 and CpG as adjuvants on the immune responses of antigen-specific CD4~+T cells in vivo / 中国免疫学杂志

ABSTRACT

Objective:To evaluate the role of IL-12 and CpG as adjuvants to promote the differentiation of antigen-specific CD4~+T cells in vivo.Methods:Naive OVA-TCR-Tg CD4~+T cells were isolated from spleens and lymph nodes of DO11.10 mice.The cells were labeled with CFSE in vitro and then were adoptively transferred into normal mice.One day after transfer,mice were immunized i.v.either with OVA,OVA+IL-12 or OVA+CpG.3 days post transfer,single cell suspensions were prepared from spleens,lymph nodes and lungs.The proliferation and IFN-? expression of transferred CD4~+T cells in different tissues were assessed by FACS.Results:No proliferation of antigen-specific CD4~+T cells was observed in the absence of immunization.After immunization with OVA for 3 days,cells were proliferated.The frequency of IFN-? producing cells in spleens,lymph nodes and lungs was at a range of 0.93%～2.17%.IL-12 promoted IFN-?~+ cells(4.53%～26.79%);Moreover,CpG enhanced the frequency of IFN-?-producing cells(3.84%) by the cells only from lymph nodes.In consistent with the results reported previously,cells divided 3-5 times revealed higher frequency of IFN-?-producing cells than the rest of them.Conclusion:IL-12 and CpG as adjuvants can promote the differentiation and expression of IFN-? by antigen-specific CD4~+T cells,and thus mediate cellular immune responses.