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
目的 克隆人 B7.1全长 c DNA及构建相应的逆转录病毒表达载体。 方法 应用逆转录多聚酶链反应从人 B淋巴瘤细胞系 Raji中克隆 B7.1全长 c DNA ,再将 c DNA插入到质粒 p Bluescript中 ,经自动荧光测序证实无误后 ,再通过定向克隆构建...目的 克隆人 B7.1全长 c DNA及构建相应的逆转录病毒表达载体。 方法 应用逆转录多聚酶链反应从人 B淋巴瘤细胞系 Raji中克隆 B7.1全长 c DNA ,再将 c DNA插入到质粒 p Bluescript中 ,经自动荧光测序证实无误后 ,再通过定向克隆构建相应的逆转录病毒表达载体 PL XSNh B7。 结果 逆转录多聚酶链反应扩增产物长度与预期的 889bp一致 ;用 M13正、反向引物进行荧光测序证实 ,克隆出的序列与 Gen Bank的 B7.1c DNA序列完全一致 ;人 B7.1全长 c DNA被成功地插入到质粒 PL XSN中。 结论 人 B7.1全长 c DNA的克隆及相应逆转录病毒表达载体的构建为今后应用 B7.1进行肿瘤免疫基因治疗提供了可能性。展开更多
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.
