Plasmids Enriched with CpG Motifs Activate Human Peripheral Blood Mononuclear Cells In Vitro and Enhance Th-1 Immune Responses to Hepatitis B Surface Antigen in Mice
Plasmids Enriched with CpG Motifs Activate Human Peripheral Blood Mononuclear Cells In Vitro and Enhance Th-1 Immune Responses to Hepatitis B Surface Antigen in Mice
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DOI：
10.1089/vim.2010.0116
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发表时间：
2011-06-01
期刊：
影响因子：
2.2
通讯作者：
Qi, Zhongtian
中科院分区：
文献类型：
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作者：
Chen, Zhihui;Cao, Jie;Qi, Zhongtian
T辅助细胞-1(Th-1)类免疫应答在乙肝病毒感染过程中对病毒的清除起着重要作用。细菌DNA中未甲基化的CpG基序可以激活Toll样受体9(TLR9)信号，并作为强大的佐剂诱导Th-1型免疫反应。在此，我们构建了一个812个碱基对的微型质粒，并以此为载体制备了一系列含有3-21个拷贝的D型CpG基序的质粒。在体外，这些富含CpG的质粒强烈刺激人外周血单个核细胞(PBMC)的增殖，并促进干扰素-γ(干扰素-γ)和白介素12(IL-12)的分泌。健康人外周血单个核细胞对该质粒的反应性强于乙肝病毒感染者。与乙肝病毒表面抗原+明胶佐剂诱导的强烈Th-2偏向应答相反，乙肝表面抗原+明胶佐剂免疫BALB/c小鼠产生了强烈的Th-1偏向应答。重组质粒可提高乙肝表面抗原特异性总免疫球蛋白G(Ig G)和Ig G(2a)的滴度。在载体存在的情况下，乙肝表面抗原特异性IL-2和干扰素-γ的产生和细胞毒活性也得到了增强。免疫反应的强度与质粒中CpG基序的数量呈正相关。这些结果表明，利用CpG富含的质粒作为重组乙肝表面抗原的佐剂，可以为开发有效的治疗疫苗提供一条有前途的、经济有效的途径。
T helper-1 (Th-1)-type immune responses play an important role in viral clearance during infection with hepatitis B virus (HBV). Unmethylated CpG motifs present in bacterial DNA can activate toll-like receptor 9 (TLR9) signals and act as potent adjuvants to induce Th-1-type immune responses. Here, a mini-plasmid with 812 base pairs in length was constructed and used as a vector to prepare a series of plasmids containing 3-21 copies of D-type CpG motifs. In vitro, these CpG-enriched plasmids strongly stimulated proliferation of human peripheral blood mononuclear cells (PBMCs) and enhanced secretion of interferon-gamma (IFN-gamma) and interleukin-12 (IL-12). The responses of the PBMCs from healthy individuals to the plasmids were stronger than those obtained from HBV-infected individuals. Contrary to the strong Th-2-biased response induced by surface antigen of hepatitis B virus (HBsAg) plus alum adjuvant, immunization of BALB/c mice with HBsAg plus these plasmids induced a strong Th-1-biased response. The plasmids increased the titers of HBsAg-specific total immunoglobulin G (IgG) and IgG(2a). HBsAg-specific IL-2 and IFN-gamma production and cytotoxic activity were also enhanced in the presence of the plasmids. The strength of the immune responses positively correlated with the number of CpG motifs in the plasmids. These results indicate that the use of CpG-enriched plasmids as an adjuvant to recombinant HBsAg could provide a promising and cost-effective approach for the development of efficacious therapeutic vaccines against HBV infection.