Blanchard D, van Els C, Borst J, Carrel S, Boylston A, de Vries J E, Spits H
J Immunol. 1987 Apr 15;138(8):2417-21.
The cytotoxic reaction mediated by cytotoxic T lymphocytes (CTL) consists of three phases: first, the CTL binds to the target cell; next, the CTL is triggered to lyse the target cell; and in the third phase, the CTL detaches from the target cell which is lysed in the absence of the CTL. Recently, we obtained evidence that human alloreactive CTL clones initially adhere to target cells without the involvement of the interaction between the T cell receptor (Tcr) and its specific target antigen. In the present study, we investigated the effect of monoclonal antibodies specific for the Tcr on the cytotoxic reaction of three CD8+ HLA-A2-specific CTL clones, using a single cell assay in which the binding event can be distinguished from the post-binding (lytic) phase of the cytolytic reaction. It was found that monoclonal antibodies directed at a variable part of the Tcr do not affect the binding phase but strongly block the lytic phase of the cytotoxic reaction. An anti-constant region Tcr antibody and an anti-CD3 reagent had a similar effect on the two phases of the reaction as the anti-variable part Tcr antibodies. In contrast, antibodies specific for LFA-1 strongly blocked the adhesion phase but did not affect the lytic phase. Antibodies specific for CD-8 had intermediate effects. They could block both the adhesion as well as the lytic phase. The effect of anti-CD8 appeared to be dependent on the CTL clone tested. One clone was found to be inhibited in the adhesion phase, but not in the lytic phase, whereas anti-CD8 hardly blocked the adhesion phase of two other CTL clones, but affected the lytic step of those clones. Our data indicate that LFA-1 is a major adhesion molecule in the CTL reaction, whereas the Tcr/CD3 complex is implicated in a phase after the initial formation of conjugates. CD8 is associated with both steps in the cytolytic reaction. In addition to its minor role in the adhesion phase, our data suggest strongly that CD-8 is involved in the triggering phase of the cytolytic reaction.
细胞毒性T淋巴细胞（CTL）介导的细胞毒性反应包括三个阶段：首先，CTL与靶细胞结合；其次，CTL被触发裂解靶细胞；在第三阶段，CTL与靶细胞分离，靶细胞在没有CTL的情况下被裂解。最近，我们获得的证据表明，人同种异体反应性CTL克隆最初附着于靶细胞，而不涉及T细胞受体（Tcr）与其特异性靶抗原之间的相互作用。在本研究中，我们使用单细胞检测法，研究了针对Tcr的单克隆抗体对三个CD8 + HLA - A2特异性CTL克隆细胞毒性反应的影响，在该检测中，结合事件可与细胞溶解反应的结合后（裂解）阶段区分开来。结果发现，针对Tcr可变部分的单克隆抗体不影响结合阶段，但强烈阻断细胞毒性反应的裂解阶段。抗恒定区Tcr抗体和抗CD3试剂对反应的两个阶段具有与抗可变部分Tcr抗体类似的作用。相比之下，针对淋巴细胞功能相关抗原-1（LFA-1）的抗体强烈阻断黏附阶段，但不影响裂解阶段。针对CD8的抗体具有中等效应。它们可以同时阻断黏附阶段和裂解阶段。抗CD8的效应似乎取决于所测试的CTL克隆。发现一个克隆在黏附阶段受到抑制，但在裂解阶段未受抑制，而抗CD8几乎不阻断另外两个CTL克隆的黏附阶段，但影响这些克隆的裂解步骤。我们的数据表明，LFA-1是CTL反应中的主要黏附分子，而Tcr/CD3复合物在结合物最初形成后的一个阶段起作用。CD8与细胞溶解反应的两个步骤都有关联。除了在黏附阶段的次要作用外，我们的数据强烈表明CD8参与细胞溶解反应的触发阶段。
