Mapping the sensitivity of T cells with an optical trap:: Polarity and minimal number of receptors for Ca2+ signaling
Mapping the sensitivity of T cells with an optical trap:: Polarity and minimal number of receptors for Ca2+ signaling
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DOI：
10.1073/pnas.96.15.8471
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发表时间：
1999-07-20
影响因子：
11.1
通讯作者：
Cahalan, MD
中科院分区：
文献类型：
--
作者：
Wei, XB;Tromberg, BJ;Cahalan, MD
与抗原呈递细胞（APC）接触会启动T淋巴细胞内的激活级联反应，包括胞质钙离子、淋巴因子产生和细胞分裂的增加。虽然T细胞-APC物理接触是免疫应答所必需的，但对细胞相互作用的模式及其与活化的关系知之甚少。钙成像结合光学陷阱，使T细胞接触的要求和极性进行调查，在单细胞水平。用激光捕获APC或抗CD 3 mAb包被的珠粒，并将其放置在T细胞的沿着不同位置，T细胞具有由爬行的形状和方向限定的极化外观。T细胞对在T细胞前缘进行的APC接触的敏感性是在尾部进行的接触的3倍。抗CD 3 mAb包被的6 μ m微珠与T细胞前缘接触时，诱导钙信号传导的频率比与后缘接触时高约10倍，潜伏期比与后缘接触时短约4倍。抗体密度（2 - 500/μ m（2））和珠粒大小（直径1 - 6 μ m）的变化用于确定空间要求和必须参与传递阳性信号的受体的最小数量。T细胞应答百分比、潜伏期和钙信号传导模式（瞬时vs.持续或振荡）取决于珠上的抗体密度。在接触区域内存在约170个抗CD 3 mAb引起可检测的T细胞钙应答。我们在这里提出，不超过340个T细胞受体（约占细胞总数的1%）的参与足以启动Ca 2+信号传导。最小接触面积约为3 μ m2。
Contact with antigen-presenting cells (APCs) initiates an activation cascade within T lymphocytes, including a rise in cytosolic calcium, lymphokine production, and cell division. Although T cell-APC physical contact is required for an immune response, little is known about the patterns of cellular interactions and their relation to activation. Calcium imaging combined with an optical trap enabled the T cell contact requirements and polarity to be investigated at the single-cell level. APCs or anti-CD3 mAb-coated beads were trapped with a laser and placed at different locations along the T cell, which has a polarized appearance defined by the shape and direction of crawling, T cells were 3-fold more sensitive to APC contact made at the leading edge of the T cell than with contact made at the tail. Anti-CD3 mAb-coated 6-mu m beads induced calcium signaling with approximate to 10-fold higher frequency and approximate to 4-fold shorter latency on contact with the leading edge of the T cell than on contact with the trailing edge. Alterations in antibody density (2 to 500 per mu m(2)) and bead size (1 to 6 mu m in diameter) were used to determine the spatial requirements and the minimal number of receptors which must be engaged to transmit a positive signal. T cell response percentage, latency, and calcium-signaling pattern (transient vs. sustained or oscillatory) depended on antibody density on the bead. The presence of approximate to 170 anti-CD3 mAb within the contact area elicited a detectable T cell calcium response. We propose here that engagement of no more than 340 T cell receptors (approximate to 1% of the total on the cell) is sufficient to initiate Ca2+ signaling. The minimal contact area was approximate to 3 mu m(2).