外源辅助T淋巴细胞表位影响HBV S基因DNA免疫的体液免疫应答

目的　探讨外源辅助T淋巴细胞 (HTL)表位对HBVS基因体液免疫应答的影响。方法选用 2种通用HTL表位 ,破伤风类毒素的氨基酸残基 (aa) 830 843片段 (TTE)和人工HTL表位(PADRE) ,以及 3种特异性HTL表位 ,结核杆菌热休克蛋白 6 5的aa1 2 0片段 (TBE)、风疹蛋白E2 4的aa5 4 6 5片段 (ME)和沙眼衣原体热休克蛋白 6 0的aa35 48片段 (CE) ,以单个表位或复合表位形式插入HBVS基因的翻译起始密码下游而构建成真核表达载体。 10 0 μg重组载体DNA免疫BALB/c小鼠 ,3周加强 1次 ,共 3次 ,第三次加强接种后 1月取血采用Abbott试剂盒检测抗 HBs。结果　HBVS基因真核表达载体pHB和 6种外源HTL表位HBVS基因真核表达载体pHB TBE、pHB PADRE、pHB TTE、pHB MTE2、pHB MTE3和pHB MTE5构建成功 ,DNA免疫的抗 HBs水平 (IU/L)分别为 10± 5 ,5± 5 ,49±7,2 9± 6 ,16± 8,2 3± 7和 2 8± 8。单个表位中 ,TTE和PADRE具有良好的免疫促进作用 ,而TBE无促进作用。复合表位均有不同程度的免疫增强作用。结论　部分外源HTL表位对HBVS基因的体液免疫应答有促进作用 ,复合表位中的单个表位间的促进作用无协同或迭加效果。表位PADRE可能用于新型高效乙肝疫苗的研制 ,而复合表位MTE5可能用于能克服人类白细胞抗原多态性的乙肝补种疫

Effect of exogenous epitopes of helper T lymphocyte on humoral immunity of HBV S gene DNA immunity

OBJECTIVE: To study the effect of exogenous epitope of helper T lymphocyte (HTL) on humoral immunity of HBV S gene DNA immunity. METHODS: Two universal HTL epitopes, amino acid residue (aa) 830-843 of the tetanus toxoid (TTE) and artificial epitope (PADRE), and 3 unique epitopes, aa1-20 of tubercle bacteria hot shock protein 65 (TBE), aa54-65 of rubella protein E2-4 (ME) and aa35-48 of trachoma hot shock protein 60 (CE) were chosen. Eukaryotic expression vectors were constructed by inserting single or multiple exogenous epitopes in HBV S gene just after the initial code of translation. BALB/c mice were inoculated with 100 micro g of recombinant DNA per mouse, and given boost inoculation for 3 times with 3-week interval. Mouse blood were collected one month just after the third boost inoculation. Anti-HBs was detected using Abbott test kits. RESULTS: HBV S eukaryotic gene expression vectors, pHB and 6 exogenous HTL epitope HBV S gene vectors, pHB-TBE, pHB-PADRE, pHB-TTE, pHB-MTE2, pHB-MTE3 and pHB-MTE5 were constructed successfully with anti-HBs level (IU/L) of 10 +/- 5, 5 +/- 5, 49 +/- 7, 29 +/- 6, 16 +/- 8, 23 +/- 7 and 28 +/- 8 respectively. Among 3 single epitopes, TTE and PADRE had obviously effect on promoting the anti-HBs response of HBV S gene, while TBE had no promoting effect. All of the 3 multiple epitopes were shown the effect of immune promoting. CONCLUSION: Some exogenous HTL epitopes had obviously effect on promoting the anti-HBs response of HBV S gene. Multiple epitopes also had humoral immunity promoting effect, but there was no synergic effect among their own HTL epitopes. PADRE might be an important candidate for new efficient HB vaccine. The multiple epitope cluster consisted form 5 exogenous epitopes might be an important candidate for the reinoculating HB vaccine or therapy HB vaccine.