白细胞介素2-乙型肝炎病毒前S抗原融合蛋白的免疫原性研究

Enhancing immunogenecity of pres antigen of hepatitis B virus by fusing genetically it with interleukin-2

为协同人白细胞介素与乙型肝炎病毒前Ｓ抗原的生物学功能，探索治疗慢性乙肝的特异性免疫药物。方法用聚合酶链反应和基因重组技术构建了ＨＢＶ完整前Ｓ抗原和ＩＬ－２的嵌合基因，并在大肠杆菌中高效表达了ＩＬ－２－前Ｓ抗原融合蛋白。结果该融合蛋白保留了ＩＬ－２和前Ｓ抗原天然分子的生物学活性，能维持白细胞介素２依赖株细胞增殖，其比活性１０＾７Ｕ／ｍｇ蛋白。

Objective To combine the bioactivities of human interleukin-2 ( IL- 2 ) with entire preS antigen of hepatitis B virus (HBV) , and search for specific immunotherapeutic agent against chronic hepatitis B. Methods A chimeric gene composed of preS gene from HBV )DNA and human IL-2 cDNA was con- structed by using polymerase chain reaction and genetic engiheering methods , and a novel type of chimeric protein (IL-2-preS) was expressed with high efficiency in E. coli ransformed by the chimeric gene clone. Results It was confirmed that the chimeric protein retained the full bioactivities of natural IL-2 and preS molecules , such as maintainig CTLL cells to proliferate , with the specific activity being about 10.u/mg protein , and binding with monoclonal antibodies against preS1 and preS2 and polymer- ized human serum albumin (PHSA ) , etc. It. was shown that the titer of antibody against preS antigen in mice induced by IL-2-preS was 9 , 11 and 13 times more than those induced by a mixture of IL-2 with preS antigen, MS- 2-preS chimeric protein and preS antigen alone , respectively. Concl uslon IL- 2-preS potentiates immunogenecity of preS antigen and enhances immune responses of hurnan bodies against preS antigen. In addition , IL-2-preS is of double targetting effect in human bodies , and may be used as a new generation of immunotherapeucic agent for chronic hepatitis B and hepatocellular carcinoma.