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Abstract：
The scanning of surrounding tissues by T lymphocytes to detect cognate antigens requires high speed, sensitivity and specificity. T-cell receptor (TCR) co-receptors such as CD8 increase detection performance, but the exact mechanism remains incompletely understood. Here, we used a laminar flow chamber to measure at the single molecule level the kinetics of bond formation and rupture between TCR- transfected CD8+ and CD8- Jurkat cells and surfaces coated with five peptide-exposing major histocompatibility antigens (pMHCs) of varying activating power. We also used interference reflection microscopy to image the spreading of these cells dropped on pMHC-exposing surfaces. CD8 did not influence the TCR-pMHC interaction during the first few seconds following cell surface encounter, but it promoted the subsequent spreading responses, suggesting that CD8 was involved in early activation rather than binding. Further, the rate and extent of spreading, but not the lag between contact and spreading initiation, depended on the pMHC. Elucidating T-lymphocyte detection strategy may help unravel underlying signaling networks.
摘要：
通过T淋巴细胞扫描周围组织以检测同源抗原需要很高的速度，敏感性和特异性。T细胞受体（TCR）共受体，如CD8增加检测性能，但确切的机制尚不完全清楚。这里,我们使用层流室在单分子水平测量了TCR转染的CD8+和CD8-Jurkat细胞与包被有5种不同活化力的肽暴露主要组织相容性抗原(pMHCs)的表面之间的键形成和断裂动力学.我们还使用干涉反射显微镜来成像这些细胞在pMHC暴露表面上的扩散。CD8在细胞表面相遇后的最初几秒钟内不影响TCR-pMHC相互作用，但它促进了随后的传播反应，提示CD8参与早期激活而非结合.Further,传播的速度和程度，但不是接触和扩散开始之间的滞后，取决于pMHC。阐明T淋巴细胞检测策略可能有助于解开潜在的信号网络。
