Al Abdullatif Sarah, Foote Alexander K, Hu Yuesong, Rogers Jhordan, Salaita Khalid
Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
Nano Lett. 2025 Sep 10;25(36):13419-13427. doi: 10.1021/acs.nanolett.5c02130. Epub 2025 Aug 25.
A key event in triggering adaptive immunity is the binding of a T cell receptor (TCR) to its antigen at the T cell-target cell interface. Mechanical forces are critical for TCR-antigen interactions, where piconewton (pN) forces modulate immune responses. A major challenge in studying these interactions is quantifying forces at the single-molecule scale, as T cells can activate in response to just 1-10 antigen molecules. To address this, we developed single-molecule DNA origami tension sensors (smDOTS) for high-resolution force mapping. Our design includes spectral fingerprint density reporters, multiple quenchers for extended force dynamics monitoring, and tunable cholesterol anchors for controlled mobility. We report unprecedented measurements of TCR-antigen forces at fluid membranes, detecting forces with magnitudes of 8 to 19 pN, and tracking ligand translocation. Multiplexing enabled the simultaneous imaging of sensors with different force thresholds. This approach could further reveal bond lifetimes and force dynamics, deepening our understanding of TCR-mediated signaling.
触发适应性免疫的一个关键事件是T细胞受体（TCR）在T细胞与靶细胞界面处与其抗原结合。机械力对TCR-抗原相互作用至关重要，其中皮牛顿（pN）力可调节免疫反应。研究这些相互作用的一个主要挑战是在单分子尺度上量化力，因为T细胞仅对1-10个抗原分子就能产生激活反应。为了解决这个问题，我们开发了用于高分辨率力映射的单分子DNA折纸张力传感器（smDOTS）。我们的设计包括光谱指纹密度报告器、用于扩展力动态监测的多个猝灭剂以及用于可控流动性的可调胆固醇锚定物。我们报告了在流体膜上对TCR-抗原力进行的前所未有的测量，检测到大小为8至19 pN的力，并跟踪配体易位。多路复用能够同时对具有不同力阈值的传感器进行成像。这种方法可以进一步揭示键寿命和力动态，加深我们对TCR介导信号传导的理解。
