Foa C, Mège J L, Capo C, Benoliel A M, Galindo J R, Bongrand P
Jeune Equipe CNRS, AIP 031 353, Marseille, France.
J Cell Sci. 1988 Apr;89 ( Pt 4):561-73. doi: 10.1242/jcs.89.4.561.
T-cell-mediated cytolysis is initiated by the formation of strong adhesions between killer and target cells. The present work was aimed at determining whether T lymphocytes might exert some mechanical stress on targets during the binding process. Target S194 myeloma cells were thus conjugated to cytotoxic T lymphocytes (CTLs) raised by mixed lymphocyte culture or a cloned lymphoid line that was no longer cytolytic (TG2OUA2). After incubation periods of various lengths, conjugates were processed for electron microscopy and micrographs were digitized for computerized analysis: the cell surface curvature (at the micrometre level) and rugosity (at the submicrometre level) were quantified in free and adhesion-involved regions. Also, the size of cell interaction areas and the distribution of intermembrane distances were measured. Finally, TG2OUA2 and target cells were aspirated into glass micropipettes with calibrated pressure in order to assay their resistance to deformation by mechanical forces. The following conclusions were suggested. (1) Formation of extensive contact zones (with a linear size of several micrometres) with tight intermembrane adhesion (more than 30% of the membrane contours in adhesive zones were separated by an apparent distance lower than 500 A) was essentially completed within less than one minute. (2) CTLs or TG2OUA2 cells were more villous than their targets, and they seemed to deform in adhesive zones in order to adapt to the target contour, rather than imposing some deformation on the target. This may be a general feature of actively adherent cells. (3) Some CTLs, but no TG2OUA2 cells, exhibited conspicuous protrusions extending towards the bound target. In this case, the target cell but not the CTL displayed markedly increased roughness in the adhesion area. (4) TG2OUA2 cells were more resistant to mechanical deformation than S194 target cells, in accordance with previous reports suggesting that the membrane of CTLs was more resistant than that of target tumour cells. Hence, CTLs might transiently impose mechanical stress on the target membrane during the course of lethal-hit delivery.
T细胞介导的细胞溶解是由杀伤细胞与靶细胞之间形成强黏附作用引发的。目前的研究旨在确定T淋巴细胞在结合过程中是否可能对靶细胞施加某种机械应力。因此，将靶标S194骨髓瘤细胞与通过混合淋巴细胞培养产生的细胞毒性T淋巴细胞（CTL）或不再具有细胞溶解能力的克隆淋巴细胞系（TG2OUA2）进行结合。在不同时长的孵育期后，对结合物进行电子显微镜处理，并将显微照片数字化以进行计算机分析：对游离区域和涉及黏附的区域的细胞表面曲率（微米水平）和粗糙度（亚微米水平）进行量化。此外，测量细胞相互作用区域的大小和膜间距离的分布。最后，将TG2OUA2细胞和靶细胞吸入带有校准压力的玻璃微量移液器中，以测定它们对机械力变形的抗性。得出了以下结论。（1）在不到一分钟的时间内，基本上就完成了具有紧密膜间黏附（黏附区域中超过30%的膜轮廓被明显距离小于500埃分隔）的广泛接触区域（线性尺寸为几微米）的形成。（2）CTL或TG2OUA2细胞比其靶细胞具有更多绒毛，并且它们似乎在黏附区域发生变形以适应靶细胞轮廓，而不是对靶细胞施加某种变形。这可能是活跃黏附细胞的一个普遍特征。（3）一些CTL，但没有TG2OUA2细胞，表现出明显的向结合的靶细胞延伸的突起。在这种情况下，靶细胞而非CTL在黏附区域显示出明显增加的粗糙度。（4）与先前报告表明CTL的膜比靶肿瘤细胞的膜更具抗性一致，TG2OUA2细胞比S194靶细胞对机械变形更具抗性。因此，CTL在致死性打击传递过程中可能会短暂地对靶细胞膜施加机械应力。
