AIM: To explore how to improve the immunogenicity of HBcAg CTL epitope based polypeptides and to trigger an HBV-specific HLA I-restricted CD8^+ T cell response in vitro.METHODS: A new panel of mimetic therapeutic pept...AIM: To explore how to improve the immunogenicity of HBcAg CTL epitope based polypeptides and to trigger an HBV-specific HLA I-restricted CD8^+ T cell response in vitro.METHODS: A new panel of mimetic therapeutic peptides based on the immunodominant B cell epitope of HBV PreS2 18-24 region, the CTL epitope of HBcAg18-27 and the universal T helper epitope of tetanus toxoid (TT) 830-843 was designed using computerized molecular design method and synthesized by Merrifield's solid-phase peptide synthesis.Their immunological properties of stimulating activation and proliferation of lymphocytes, of inducing TN1 polarization,CD8^+ T cell magnification and HBV-specific CD8^+ CTL mediated cytotoxicity were investigated in vitro using HLA-A2^+ human peripheral blood mononuclear cells (PBMCs) from healthy donors and chronic hepatitis B patients.RESULTS: Results demonstrated that the therapeutic polypeptides based on immunodominant HBcAg18-27 CTL,PreS2 B- and universal TN epitopes could stimulate the activation and proliferation of lymphocytes, induce specifically and effectively CD8+ T cell expansion and vigorous HBVspecific CTL-mediated cytotoxicity in human PBMCs.CONCLUSION: It indicated that the introduction of immunodominant T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of short CTL epitopes in vitro.展开更多
To investigate the role of CD4 + helper T (Th) cells in the memory CTL-mediated anti-tumor immunity, the RAG-1 gene knock out mice were adoptively transferred with OT-1 cells to generate the memory CTL, the C57BL/6 mi...To investigate the role of CD4 + helper T (Th) cells in the memory CTL-mediated anti-tumor immunity, the RAG-1 gene knock out mice were adoptively transferred with OT-1 cells to generate the memory CTL, the C57BL/6 mice immunized with the epitope peptide of OVA specific Th cells and with different adjuvants were adoptively transferred with these memory-CTLs, and then the animals were challenged with tumor cells EG7. It was found that although the simple immunization of mice with the epitope peptide of the OVA specific Th cells could generate more effect CTL, but this effect was not so strong enough to resist completely the challenges with tumor cells. Nevertheless, the memory CTL-mediated anti-tumor immune effect required the helps of Th1 and Th2 cells. The cross-regulation between Th1 and Th2 cells seemed to be beneficial for the host to generate more effector CTL for mounting an efficient anti-tumor response. It concluded that the interaction between Th1 and Th2 cells might be more important than the single subset of Th cells in the memory CTL-mediated anti-tumor immune response. More attention should be paid in this regard for the future studies.展开更多
【目的】监测当前湖南省猪圆环病毒2型(Porcine circovirus type 2,PCV2)流行毒株及其衣壳蛋白(capsid protein,Cap)变异情况,并预测Cap蛋白细胞毒性T淋巴细胞(cytotoxic T lymphocyte,CTL)表位,为新型PCV2疫苗研制和病毒净化提供参考...【目的】监测当前湖南省猪圆环病毒2型(Porcine circovirus type 2,PCV2)流行毒株及其衣壳蛋白(capsid protein,Cap)变异情况,并预测Cap蛋白细胞毒性T淋巴细胞(cytotoxic T lymphocyte,CTL)表位,为新型PCV2疫苗研制和病毒净化提供参考依据。【方法】本研究对2019-2021年于湖南省6个地区收集的17份PCV2阳性组织样品进行PCV2全基因组序列扩增及测序分析,绘制系统进化树,利用生物信息学方法分析Cap蛋白氨基酸变异情况,并预测CTL表位。【结果】系统进化树显示,获得的17株PCV2全基因组序列中,1株PCV2a、7株PCV2b和9株PCV2d。Cap蛋白氨基酸序列比对分析发现,共有16个氨基酸残基突变位点位于病毒Cap蛋白表面,且有11个突变位点参与构象型表位的形成。此外,共预测出9个PCV2 Cap蛋白潜在的CTL表位,其中4个表位(16-24、28-36、136-144和179-187位氨基酸)在GenBank的1610株PCV2不同基因型毒株中高度保守。通过TCR-pMHC复合物3D结构对4个保守性表位进一步分析,结果显示,这4个肽段均能与MHCⅠ分子和TCR形成稳定的TCR-pMHC复合物。【结论】本研究结果表明,PCV2b和PCV2d为当前湖南省主要流行的基因型,且表现出高度变异;预测的CTL表位可作为候选抗原表位。展开更多
基金Supported by the National Natural Science Foundation of China,No.30271189the National 973 Project,No.2001CB510001
文摘AIM: To explore how to improve the immunogenicity of HBcAg CTL epitope based polypeptides and to trigger an HBV-specific HLA I-restricted CD8^+ T cell response in vitro.METHODS: A new panel of mimetic therapeutic peptides based on the immunodominant B cell epitope of HBV PreS2 18-24 region, the CTL epitope of HBcAg18-27 and the universal T helper epitope of tetanus toxoid (TT) 830-843 was designed using computerized molecular design method and synthesized by Merrifield's solid-phase peptide synthesis.Their immunological properties of stimulating activation and proliferation of lymphocytes, of inducing TN1 polarization,CD8^+ T cell magnification and HBV-specific CD8^+ CTL mediated cytotoxicity were investigated in vitro using HLA-A2^+ human peripheral blood mononuclear cells (PBMCs) from healthy donors and chronic hepatitis B patients.RESULTS: Results demonstrated that the therapeutic polypeptides based on immunodominant HBcAg18-27 CTL,PreS2 B- and universal TN epitopes could stimulate the activation and proliferation of lymphocytes, induce specifically and effectively CD8+ T cell expansion and vigorous HBVspecific CTL-mediated cytotoxicity in human PBMCs.CONCLUSION: It indicated that the introduction of immunodominant T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of short CTL epitopes in vitro.
文摘To investigate the role of CD4 + helper T (Th) cells in the memory CTL-mediated anti-tumor immunity, the RAG-1 gene knock out mice were adoptively transferred with OT-1 cells to generate the memory CTL, the C57BL/6 mice immunized with the epitope peptide of OVA specific Th cells and with different adjuvants were adoptively transferred with these memory-CTLs, and then the animals were challenged with tumor cells EG7. It was found that although the simple immunization of mice with the epitope peptide of the OVA specific Th cells could generate more effect CTL, but this effect was not so strong enough to resist completely the challenges with tumor cells. Nevertheless, the memory CTL-mediated anti-tumor immune effect required the helps of Th1 and Th2 cells. The cross-regulation between Th1 and Th2 cells seemed to be beneficial for the host to generate more effector CTL for mounting an efficient anti-tumor response. It concluded that the interaction between Th1 and Th2 cells might be more important than the single subset of Th cells in the memory CTL-mediated anti-tumor immune response. More attention should be paid in this regard for the future studies.
文摘【目的】监测当前湖南省猪圆环病毒2型(Porcine circovirus type 2,PCV2)流行毒株及其衣壳蛋白(capsid protein,Cap)变异情况,并预测Cap蛋白细胞毒性T淋巴细胞(cytotoxic T lymphocyte,CTL)表位,为新型PCV2疫苗研制和病毒净化提供参考依据。【方法】本研究对2019-2021年于湖南省6个地区收集的17份PCV2阳性组织样品进行PCV2全基因组序列扩增及测序分析,绘制系统进化树,利用生物信息学方法分析Cap蛋白氨基酸变异情况,并预测CTL表位。【结果】系统进化树显示,获得的17株PCV2全基因组序列中,1株PCV2a、7株PCV2b和9株PCV2d。Cap蛋白氨基酸序列比对分析发现,共有16个氨基酸残基突变位点位于病毒Cap蛋白表面,且有11个突变位点参与构象型表位的形成。此外,共预测出9个PCV2 Cap蛋白潜在的CTL表位,其中4个表位(16-24、28-36、136-144和179-187位氨基酸)在GenBank的1610株PCV2不同基因型毒株中高度保守。通过TCR-pMHC复合物3D结构对4个保守性表位进一步分析,结果显示,这4个肽段均能与MHCⅠ分子和TCR形成稳定的TCR-pMHC复合物。【结论】本研究结果表明,PCV2b和PCV2d为当前湖南省主要流行的基因型,且表现出高度变异;预测的CTL表位可作为候选抗原表位。
