含CpG免疫刺激序列的质粒增强HBsAg诱导的免疫应答

Multi-copy CpG ODN-containing plasmid enhancing immune responses to HBsAg

目的探讨以含有多拷贝CpG寡脱氧核苷酸(CpG ODN)的质粒作为治疗性乙肝疫苗佐剂的可行性。方法构建含有6个拷贝D型CpG ODN的质粒pKO-CG6,将该质粒以及载体pKO分别刺激健康人及HBV感染者的外周血单核细胞(PBMC),检测PBMC的增殖及分泌的细胞因子IFN-γ、IL-12,进一步将重组HBsAg分别联合这两种质粒免疫小鼠,检测小鼠的细胞和体液免疫应答。结果质粒pKO-CG6与载体pKO在体外均能有效激活健康人及HBV感染者PBMC增殖反应,并促进IFN-γ、IL-12的产生,其中pKO-CG6的免疫刺激活性强于载体pKO。小鼠体内试验表明,虽然载体pKO也具有免疫佐剂作用,但pKO-CG6更能显著增强HBsAg诱导的免疫应答,尤其是细胞免疫应答。结论含有多拷贝D型CpG ODN的质粒能有效激活HBV感染者的PBMC,并增强HBsAg在小鼠体内的免疫原性。

Objective To explore the possibility of using plasmid containing muti-copy of CpG ODN as the adjuvant for therapeutic vaccine against hepatitis B.Methods A plasmid pKO-CG6 containing six copies of D type CpG ODN was constructed.The plasmid and the carrier plasmid pKO were used to stimulate peripheral blood monouclear cells（PBMC） of healthy or HBV infected subjects;then the proliferation of PBMCs and secretion of IFN-γ and IL-12 were examined.Recombinant HBsAg combined with either of the plasmid was used to immunize BALB/c mice,and immune responses to HBsAg were assayed.Results Both plasmid pKO-CG6 and carrier plasmid pKO not only effectively activated the proliferation response of PBMCs from healthy controls and HBV infected subjects in vitro,but also promoted the production of IFN-γ and IL-12;the immuno-stimulation activity of pKO-CG6 was greatly stronger than that of the carrier plasmid pKO.In vivo study showed that although vector pKO could also act as immunological adjuvant for HBsAg in mice,plasmid pKO-CG6 elicited much stronger immune responses to HBsAg,especially the cell-mediated response.Conclusion Plasmid containing multi-copy of CpG ODN can effectively activate PBMCs of HBV infected subjects and enhance the immune responses to HBsAg in mice.