Regulation of Cell survival Following T Cell Recognition

描述(由申请人提供)：这些研究人员先前已经展示了通过基因转导抗凋亡的抗caspase-2基因来实现人脐静脉内皮细胞(HUVEC)免受人细胞毒性T淋巴细胞(HuCTL)的细胞保护的有效策略。相反，转Bcl2基因的猪主动脉内皮细胞(PAEC)对某些凋亡诱导剂耐受，但对异种huCTL敏感。比较这些转导线路的敏感性表明，与人EC相比，猪EC的敏感性代表了功能的获得。敏感性的差异将根据Fas介导的信号通路的调节因素来表征，而caspase的激活程度将通过生物化学来表征。在此基础上，我们将进一步研究更多的基因，以进一步实现PAEC的体外细胞保护作用。调节性T细胞可以抑制CD_4和CD_8两种T细胞的活性，在调节自身免疫和移植的发展中发挥重要作用。将分离出原型的CD4+CD25+调节性T细胞，并对其功能和生化特性进行鉴定。这些调节细胞用来抑制与CD4和CD8T细胞的同种和异种相互作用的机制将被比较。这些细胞类型为减少移植排斥反应提供了另一种策略。最后，使用SCID/褐鼠的活体模型将被用来评估细胞保护策略和调节性T细胞的功能。已经建立了一种方案，非常有效地显示了通过Bcl-2转导对人微血管的细胞保护。我们将利用这个模型来研究使用猪微血管的细胞保护策略。

DESCRIPTION (provided by applicant): These investigators have previously shown effective strategies to achieve cytoprotection of human umbilical vein endothelial cells (HUVEC) from human cytotoxic T lymphocytes (huCTL) by genetic transduction of the anti-apoptotic caspase-resistant Bcl-2 gene. By contrast, porcine aortic endothelial cells (PAEC) transduced with Bcl-2 are resistant to some inducers of apoptosis but sensitive to xenogeneic huCTL. Comparison of the sensitivity of these transduced lines suggests that the sensitivity of porcine EC represents a gain of function when compared to human EC. The differences in sensitivity will be characterized with regard to factors regulating the Fas mediated signaling pathway and the extent of caspase activation will be characterized biochemically. Based on this characterization additional genes will be examined to further achieve cytoprotection of PAEC in vitro. The activity of both CD4 and CD8 T cells can be inhibited by cells known as regulatory T cells, which may play important roles in regulating development of autoimmunity and transplantation. The prototypic CD4+CD25+ regulatory T cells will be isolated and characterized functionally and biochemically. The mechanisms these regulatory cells utilize to inhibit allo- and xeno- interactions with CD4 and CD8 T cells will be compared. These cell types offer an additional strategy to reduce graft rejection. Finally, in vivo models using SCID/beige mice will be utilized to evaluate cytoprotective strategies and the function of regulatory T cells. A protocol has been established that very effectively shows cytoprotection of human microvessels by Bcl-2 transduction. We will utilize this model to study cytoprotective strategies using porcine microvessels.