Channarong Sunee, Mitrevej Ampol, Sinchaipanid Nuttanan, Usuwantim Kanchana, Kulkeaw Kasem, Chaicumpa Wanpen
Faculty of Pharmacy, Mahidol University, Bangkok.
Asian Pac J Allergy Immunol. 2007 Dec;25(4):233-42.
Hepatitis B is a global serious disease caused by hepatitis B virus (HBV). There is no known cure for hepatitis B. The best way to deal with the disease is by preventing with hepatitis B vaccine. However, the current protein-based vaccines made up of recombinant hepatitis B surface antigen (HBsAg) are ineffective in chronic HBV carriers and a significant number of the vaccinees do not mount the protective immune response. Novel DNA-based immunization may overcome the deficits of the protein-based immunization and may provide more effective prophylactic and therapeutic outcomes. In this study, we constructed a recombinant plasmid carrying gene encoding the HBV surface antigen (HBs) linked to DNA segment encoding full-length murine interleukin-18, i.e. pcDNA-HBs-IL-18. Immunogenicity of the DNA construct was carried out in BALB/c mice in comparison with mock, i.e. pcDNA3.1+ and vaccines comprised of pRc/CMV-HBs and pRc/CMV-HBs plus pcDNA-IL-18. All vaccinated mice revealed significant serum anti-HBs IgG response after two intramuscular injections of the vaccines at 28 day interval as compared to the level of mock. Co-administration of pRc/CMV-HBs and pcDNA-IL-18 elicited arbitrarily higher levels of anti-HBs IgG than the levels in mice immunized with pRc/CMV-HBs alone and mice that received pcDNA-HBs-IL-18 although not statistically different. Further experiments are needed to investigate the subisotypes of the IgG antibody, the kinetics of cytokine and the cell-mediated immune response. For this communication, the prototype HBs-IL-18 DNA vaccine was successfully constructed and the gene encoding murine IL-18 was successfully cloned. The latter can be co-injected with the antigen coding DNA or used as a fusion partner to the DNA for priming the immune response. The recombinant HBs and full-length IL-18 proteins have potential for other research purposes. They may be used also as standard proteins in the protein quantification assay.
乙型肝炎是一种由乙型肝炎病毒（HBV）引起的全球性严重疾病。目前尚无治愈乙型肝炎的方法。应对该疾病的最佳方式是通过接种乙型肝炎疫苗进行预防。然而，目前由重组乙型肝炎表面抗原（HBsAg）构成的基于蛋白质的疫苗对慢性HBV携带者无效，并且大量接种者无法产生保护性免疫反应。新型基于DNA的免疫接种可能克服基于蛋白质的免疫接种的缺陷，并可能提供更有效的预防和治疗效果。在本研究中，我们构建了一种重组质粒，其携带编码与编码全长小鼠白细胞介素-18的DNA片段相连的HBV表面抗原（HBs）的基因，即pcDNA-HBs-IL-18。与空载体（即pcDNA3.1+）以及由pRc/CMV-HBs和pRc/CMV-HBs加pcDNA-IL-18组成的疫苗相比，在BALB/c小鼠中对该DNA构建体的免疫原性进行了研究。与空载体组相比，所有接种疫苗的小鼠在以28天的间隔进行两次肌肉注射疫苗后均显示出显著的血清抗-HBs IgG反应。pRc/CMV-HBs和pcDNA-IL-18联合给药诱导产生的抗-HBs IgG水平比单独用pRc/CMV-HBs免疫的小鼠以及接受pcDNA-HBs-IL-18的小鼠的水平任意更高，尽管无统计学差异。需要进一步的实验来研究IgG抗体的亚类、细胞因子的动力学以及细胞介导免疫反应。就本交流而言，成功构建了原型HBs-IL-18 DNA疫苗，并成功克隆了编码小鼠IL-18的基因。后者可与抗原编码DNA共同注射或用作DNA的融合伴侣以引发免疫反应。重组HBs和全长IL-18蛋白具有用于其他研究目的的潜力。它们也可在蛋白质定量测定中用作标准蛋白。
