Rollins S A, Kennedy S P, Chodera A J, Elliott E A, Zavoico G B, Matis L A
Department of Immunobiology, Alexion Pharmaceuticals, Inc., New Haven Connecticut 06511.
Transplantation. 1994 Jun 27;57(12):1709-16.
In this study we present a comprehensive evaluation of the molecular interactions between human T cells and porcine aortic endothelial cells (PAEC) that contribute to human T cell activation. Binding assays demonstrated that porcine erythrocytes (E) and PAEC express ligand(s) for the human T cell glycoprotein CD2. Prior incubation of human T cells with a blocking monoclonal antibody directed against CD2 (alpha CD2-BL) completely inhibited T cell/E and T cell/PAEC interaction. Xenogeneic mixed lymphocyte reactions (XMLR) revealed that human PBMC, or highly purified T cells were activated by PAEC in the absence of human antigen-presenting cells (APC). Addition of alpha CD2-BL or alpha LFA-1 to these assays inhibited PAEC-mediated human T cell activation. Furthermore, we demonstrated that highly purified human CD4+ and CD8+ T cells proliferated in response to PAEC and that this response was blocked by monoclonal antibodies directed against LFA-1 and CD2. Addition of alpha SLA class I blocked the proliferation of CD8+ but not CD4+ T cells, indicating direct presentation of SLA class I antigens to human T cells. We have recently shown that expression of the human complement inhibitor (CD59) on PAEC (PAEC-LXSNCD59) rendered these cells resistant to human complement-mediated activation and lysis, suggesting that human CD59 expression on PAEC could be an effective therapy for hyperacute rejection (HAR). However, recent studies have shown that in addition to its role as a complement inhibitor, CD59 binds human T cell CD2 and contributes to T cell activation. We therefore examined whether human CD59 expression on PAEC augmented the human antiporcine T cell response. We demonstrated that human T cells do not display increased binding to or activation by PAEC-LXSNCD59 relative to PAEC controls. Taken together, our data establish that PAEC directly stimulate human T cells in vitro and that interactions between the human accessory molecules CD2, LFA-1 and their PAEC surface ligands contribute to human T cell activation. In addition, the expression of human CD59 on porcine donor organs may confer resistance to human complement-mediated HAR without exacerbating the human antiporcine cellular response.
在本研究中，我们对导致人类T细胞活化的人类T细胞与猪主动脉内皮细胞（PAEC）之间的分子相互作用进行了全面评估。结合试验表明，猪红细胞（E）和PAEC表达人类T细胞糖蛋白CD2的配体。用人T细胞与针对CD2的阻断性单克隆抗体（αCD2 - BL）预先孵育，可完全抑制T细胞/E和T细胞/PAEC的相互作用。异种混合淋巴细胞反应（XMLR）显示，在不存在人类抗原呈递细胞（APC）的情况下，人类PBMC或高度纯化的T细胞可被PAEC激活。在这些试验中添加αCD2 - BL或αLFA - 1可抑制PAEC介导的人类T细胞活化。此外，我们证明高度纯化的人类CD4⁺和CD8⁺T细胞可对PAEC产生增殖反应，且这种反应可被针对LFA - 1和CD2的单克隆抗体阻断。添加αSLA I类分子可阻断CD8⁺但不阻断CD4⁺T细胞的增殖，表明SLA I类抗原可直接呈递给人类T细胞。我们最近发现，PAEC（PAEC - LXSNCD59）上人类补体抑制剂（CD59）的表达使这些细胞对人类补体介导的活化和裂解具有抗性，这表明PAEC上人类CD59的表达可能是治疗超急性排斥反应（HAR）的有效方法。然而，最近的研究表明，除了作为补体抑制剂的作用外，CD59还与人T细胞CD2结合并促进T细胞活化。因此，我们研究了PAEC上人类CD59的表达是否增强了人类抗猪T细胞反应。我们证明，相对于PAEC对照，人类T细胞与PAEC - LXSNCD59的结合或活化并未增加。综上所述，我们的数据表明，PAEC在体外可直接刺激人类T细胞，人类辅助分子CD2、LFA - 1与其PAEC表面配体之间的相互作用有助于人类T细胞活化。此外，猪供体器官上人类CD59的表达可能赋予对人类补体介导的HAR的抗性，而不会加剧人类抗猪细胞反应。
