Laboratory of Applied Mechanobiology, Department for Health Sciences and Technology, ETH Zürich, 8093 Zürich, Switzerland.
Institute of Biology, Experimental Biophysics/Mechanobiology, Humboldt Universität zu Berlin, 10115 Berlin, Germany.
Nano Lett. 2021 Jan 13;21(1):507-514. doi: 10.1021/acs.nanolett.0c03964. Epub 2020 Dec 11.
When T-cells probe their environment for antigens, the bond between the T-cell receptor (TCR) and the peptide-loaded major histocompatibility complex (MHC) is put under tension, thereby influencing the antigen discrimination. Yet, the quantification of such forces in the context of T-cell signaling is technically challenging. Here, we developed a traction force microscopy platform which allows for quantifying the pulls and pushes exerted via T-cell microvilli, in both tangential and normal directions, during T-cell activation. We immobilized specific T-cell activating antibodies on the marker beads used to read out the hydrogel deformation. Microvilli targeted the functionalized beads, as confirmed by superresolution microscopy of the local actin organization. Moreover, we found that cellular components, such as actin, TCR, and CD45 reorganize upon interaction with the beads, such that actin forms a vortex-like ring structure around the beads and TCR is enriched at the bead surface, whereas CD45 is excluded from bead-microvilli contacts.
当 T 细胞探测其环境中的抗原时,T 细胞受体(TCR)与肽负载的主要组织相容性复合体(MHC)之间的键会受到张力的影响,从而影响抗原的识别。然而,在 T 细胞信号转导的背景下,对这种力进行定量是具有技术挑战性的。在这里,我们开发了一种牵引力显微镜平台,该平台允许在 T 细胞激活过程中定量测量通过 T 细胞微绒毛在切向和法向方向上施加的拉力和推力。我们将特定的 T 细胞激活抗体固定在用于读取水凝胶变形的标记珠上。微绒毛靶向功能化的珠子,这一点通过对局部肌动蛋白组织的超分辨率显微镜得到了证实。此外,我们发现细胞成分,如肌动蛋白、TCR 和 CD45,在与珠子相互作用时会发生重排,使得肌动蛋白在珠子周围形成涡旋状的环结构,而 TCR 在珠表面富集,而 CD45 则从珠-微绒毛接触中排除。