Cole David K, Pumphrey Nicholas J, Boulter Jonathan M, Sami Malkit, Bell John I, Gostick Emma, Price David A, Gao George F, Sewell Andrew K, Jakobsen Bent K
Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom.
J Immunol. 2007 May 1;178(9):5727-34. doi: 10.4049/jimmunol.178.9.5727.
T cell recognition is initiated by the binding of TCRs to peptide-MHCs (pMHCs), the interaction being characterized by weak affinity and fast kinetics. Previously, only 16 natural TCR/pMHC interactions have been measured by surface plasmon resonance (SPR). Of these, 5 are murine class I, 5 are murine class II, and 6 are human class I-restricted responses. Therefore, a significant gap exists in our understanding of human TCR/pMHC binding due to the limited SPR data currently available for human class I responses and the absence of SPR data for human class II-restricted responses. We have produced a panel of soluble TCR molecules originating from human T cells that respond to naturally occurring disease epitopes and their cognate pMHCs. In this study, we compare the binding affinity and kinetics of eight class-I-specific TCRs (TCR-Is) to pMHC-I with six class-II-specific TCRs (TCR-IIs) to pMHC-II using SPR. Overall, there is a substantial difference in the TCR-binding equilibrium constants for pMHC-I and pMHC-II, which arises from significantly faster on-rates for TCRs binding to pMHC-I. In contrast, the off-rates for all human TCR/pMHC interactions fall within a narrow window regardless of class restriction, thereby providing experimental support for the notion that binding half-life is the principal kinetic feature controlling T cell activation.
T细胞识别是由TCR与肽-主要组织相容性复合体（pMHC）结合启动的，这种相互作用的特点是亲和力弱且动力学速度快。此前，通过表面等离子体共振（SPR）仅测量了16种天然TCR/pMHC相互作用。其中，5种是小鼠I类，5种是小鼠II类，6种是人类I类限制反应。因此，由于目前可用于人类I类反应的SPR数据有限，且缺乏人类II类限制反应的SPR数据，我们对人类TCR/pMHC结合的理解存在显著差距。我们制备了一组源自人类T细胞的可溶性TCR分子，它们对天然存在的疾病表位及其同源pMHC有反应。在本研究中，我们使用SPR比较了8种I类特异性TCR（TCR-I）与pMHC-I的结合亲和力和动力学，以及6种II类特异性TCR（TCR-II）与pMHC-II的结合亲和力和动力学。总体而言，pMHC-I和pMHC-II的TCR结合平衡常数存在显著差异，这是由于TCR与pMHC-I结合的结合速率明显更快。相比之下，所有人类TCR/pMHC相互作用的解离速率都在一个狭窄的范围内，而与类别限制无关，从而为结合半衰期是控制T细胞激活的主要动力学特征这一观点提供了实验支持。
