目的探讨融合蛋白CTLA4.FasL对肝前体细胞(LEPCs)增殖分化潜能的影响及抑制异种排斥反应的效应。方法克隆CTLA4.FasL基因,构建携带CTLA4.FasL基因与红色荧光蛋白(mCherry)双顺反子结构的重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry。优...目的探讨融合蛋白CTLA4.FasL对肝前体细胞(LEPCs)增殖分化潜能的影响及抑制异种排斥反应的效应。方法克隆CTLA4.FasL基因,构建携带CTLA4.FasL基因与红色荧光蛋白(mCherry)双顺反子结构的重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry。优化慢病毒感染LEPCs的条件,建立高表达CTLA4.FasL的LEPCs,荧光显微镜观察mCherry的表达,Western blot检测CTLA4.FasL的表达,酶联免疫吸附测定法(ELISA)测定细胞培养上清中CTLA4.FasL的浓度,水溶性四氮唑(WST-1)法检测细胞的增殖活性,Real time PCR(RT-PCR)检测干细胞相关基因CK19和c-Kit mRNA的表达,5-溴脱氧尿嘧啶核苷(Brdu)掺入法测定CTLA4.FasL-LEPCs在异种混合淋巴细胞培养体系中对大鼠淋巴细胞增殖的抑制作用。结果构建重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry,病毒滴度为2×108 TU/mL。在感染复数(multiplicity of infection,MOI)为10,聚凝胺质量浓度是5μg/mL时,感染效率约90%。Western blot证实了CTLA4.FasL的表达,在细胞培养上清中其质量浓度约为(0.72±0.10)μg/mL。CTLA4.FasL-LEPCs细胞增殖活性未受到影响,CK19和c-Kit基因mRNA表达水平无变化。CTLA4.FasL-LEPCs细胞可显著抑制大鼠淋巴细胞的增殖(P<0.05)。结论构建成功的重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry可介导CTLA4.FasL基因在LEPCs中高效表达;CTLA4.FasL可有效地抑制异种排斥反应,同时不损害LEPCs增殖活性和分化潜能。展开更多
The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the int...The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the interaction of CD3/TCR complex with Ag/MHC complex presented on antigen presenting cells, a complete T cell activation and proliferation requires a second costimulatory signal. The interaction of CD28/CTLA 4 and B7 is a major costimulatory pathway for T Cell activation. Inhibition of this pathway results in development of antigen specific unresponsiveness and clonal anergy.In present study,the biologic function of anti CD28 monoclonal antibody and its Fab fragment were investigated in vitro and in vivo.The results indicate that mAbCD28 and its Fab fragments could promote the functional recovery of allografts and prolong the graft survival,but could not reverse the acute rejection or induce transplantation tolerance in the rat PTG allograft model. We also found that peripheral TNF α level and NK cell activity were suppressed in the presence of mAbCD28 and its Fab fragments for a relatively long time after PTG transplantation.展开更多
文摘目的探讨融合蛋白CTLA4.FasL对肝前体细胞(LEPCs)增殖分化潜能的影响及抑制异种排斥反应的效应。方法克隆CTLA4.FasL基因,构建携带CTLA4.FasL基因与红色荧光蛋白(mCherry)双顺反子结构的重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry。优化慢病毒感染LEPCs的条件,建立高表达CTLA4.FasL的LEPCs,荧光显微镜观察mCherry的表达,Western blot检测CTLA4.FasL的表达,酶联免疫吸附测定法(ELISA)测定细胞培养上清中CTLA4.FasL的浓度,水溶性四氮唑(WST-1)法检测细胞的增殖活性,Real time PCR(RT-PCR)检测干细胞相关基因CK19和c-Kit mRNA的表达,5-溴脱氧尿嘧啶核苷(Brdu)掺入法测定CTLA4.FasL-LEPCs在异种混合淋巴细胞培养体系中对大鼠淋巴细胞增殖的抑制作用。结果构建重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry,病毒滴度为2×108 TU/mL。在感染复数(multiplicity of infection,MOI)为10,聚凝胺质量浓度是5μg/mL时,感染效率约90%。Western blot证实了CTLA4.FasL的表达,在细胞培养上清中其质量浓度约为(0.72±0.10)μg/mL。CTLA4.FasL-LEPCs细胞增殖活性未受到影响,CK19和c-Kit基因mRNA表达水平无变化。CTLA4.FasL-LEPCs细胞可显著抑制大鼠淋巴细胞的增殖(P<0.05)。结论构建成功的重组慢病毒载体Lv-CTLA4.FasL-IRES-mCherry可介导CTLA4.FasL基因在LEPCs中高效表达;CTLA4.FasL可有效地抑制异种排斥反应,同时不损害LEPCs增殖活性和分化潜能。
文摘The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the interaction of CD3/TCR complex with Ag/MHC complex presented on antigen presenting cells, a complete T cell activation and proliferation requires a second costimulatory signal. The interaction of CD28/CTLA 4 and B7 is a major costimulatory pathway for T Cell activation. Inhibition of this pathway results in development of antigen specific unresponsiveness and clonal anergy.In present study,the biologic function of anti CD28 monoclonal antibody and its Fab fragment were investigated in vitro and in vivo.The results indicate that mAbCD28 and its Fab fragments could promote the functional recovery of allografts and prolong the graft survival,but could not reverse the acute rejection or induce transplantation tolerance in the rat PTG allograft model. We also found that peripheral TNF α level and NK cell activity were suppressed in the presence of mAbCD28 and its Fab fragments for a relatively long time after PTG transplantation.
