Visualization of Cell-Cell Interaction Contacts: Synapses and Kinapses.

T-cell activation requires interactions of T-cell antigen receptors (TCR) and peptides presented by major histocompatibility complex molecules (MHCp) in an adhesive junction between the T-cell and antigen-presenting cell (APC). Stable junctions with bull's eye supramolecular activation clusters (SMACs) have been defined as immunological synapses. The term synapse works in this case because it joins roots for "same" and "fasten," which could be translated as "fasten in the same place." These structures maintain T-cell-APC interaction and allow directed secretion. We have proposed that SMACs are not really clusters, but are analogous to higher order membrane-cytoskeleton zones involved in amoeboid locomotion including a substrate testing lamellipodium, an adhesive lamella and anti-adhesive uropod. Since T-cells can also integrate signaling during locomotion over antigen presenting cells, it is important to consider adhesive junctions maintained as cells move past each other. This combination of movement (kine-) and fastening (-apse) can be described as a kinapse or moving junction. Synapses and kinapses operate in different stages of T-cell priming. Optimal effector functions may also depend upon cyclical use of synapses and kinapses. Visualization of these structures in vitro and in vivo presents many distinct challenges that will be discussed in this paper.

T细胞活化需要T细胞抗原受体（TCR）与主要组织相容性复合体分子（MHCp）所呈递的肽段在T细胞和抗原呈递细胞（APC）之间的黏附连接部位相互作用。具有牛眼状超分子活化簇（SMACs）的稳定连接已被定义为免疫突触。在这种情况下使用“突触”这个术语是因为它结合了“相同”和“固定”的词根，可译为“在同一位置固定”。这些结构维持T细胞 - APC相互作用并允许定向分泌。我们提出，SMACs实际上并非簇状，而是类似于参与变形虫运动的高阶膜 - 细胞骨架区域，包括一个底物探测片足、一个黏附片层和一个抗黏附尾足。由于T细胞在抗原呈递细胞上移动时也能整合信号，所以考虑细胞相互移动时所维持的黏附连接是很重要的。这种运动（kine -）和固定（ - apse）的结合可被描述为动合连接（kinapse）或移动连接。突触和动合连接在T细胞启动的不同阶段起作用。最佳效应功能可能也取决于突触和动合连接的周期性使用。在体外和体内对这些结构进行可视化呈现出许多独特的挑战，本文将对此进行讨论。