TCR-peptide-MHC interactions in situ show accelerated kinetics and increased affinity.
TCR-peptide-MHC interactions in situ show accelerated kinetics and increased affinity.
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T淋巴细胞对外来抗原的识别对于大多数适应性免疫应答是必不可少的。它是由特异性T细胞抗原受体（TCR）与其他细胞上的抗原肽-主要组织相容性复合物（pMHC）分子结合驱动的。如果有效，这些相互作用促进免疫突触的形成。在这里，我们表明，突触TCR-pMHC结合动力学显着不同的TCR-pMHC结合在溶液中。我们使用单分子显微镜和荧光标记的TCR和它们的同源pMHC配体之间的荧光共振能量转移（FRET）来测量TCR-pMHC原位结合的动力学。当与溶液测量相比时，该复合物的解离显著增加（4-12倍）。破坏肌动蛋白聚合物逆转这种效果，表明细胞骨架动力学不稳定这种相互作用直接或间接。然而，TCR对pMHC的亲和力显著升高，这是由于结合率大幅增加（约100倍），这可能是互补分子取向和聚类的结果。在辅助性T细胞中，已经提出CD 4分子与TCR协同结合至相同的pMHC复合物。然而，CD 4阻断对突触TCR亲和力没有影响，也没有使TCR-pMHC复合物不稳定，表明TCR独立于CD 4结合pMHC。
The recognition of foreign antigens by T lymphocytes is essential to most adaptive immune responses. It is driven by specific T-cell antigen receptors (TCRs) binding to antigenic peptide–major histocompatibility complex (pMHC) molecules on other cells. If productive, these interactions promote the formation of an immunological synapse. Here we show that synaptic TCR–pMHC binding dynamics differ significantly from TCR–pMHC binding in solution. We used single-molecule microscopy and fluorescence resonance energy transfer (FRET) between fluorescently tagged TCRs and their cognate pMHC ligands to measure the kinetics of TCR–pMHC binding in situ. When compared with solution measurements, the dissociation of this complex was increased significantly (4–12-fold). Disruption of actin polymers reversed this effect, indicating that cytoskeletal dynamics destabilize this interaction directly or indirectly. Nevertheless, TCR affinity for pMHC was significantly elevated as the result of a large (about 100-fold) increase in the association rate, a likely consequence of complementary molecular orientation and clustering. In helper T cells, the CD4 molecule has been proposed to bind cooperatively with the TCR to the same pMHC complex. However, CD4 blockade had no effect on the synaptic TCR affinity, nor did it destabilize TCR–pMHC complexes, indicating that the TCR binds pMHC independently of CD4.
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影响因子：
32.4
作者：
Sykulev, Y;Joo, M;Eisen, HN
通讯作者：
Eisen, HN
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64.8
作者：
Monks, CRF;Freiberg, BA;Kupfer, A
通讯作者：
Kupfer, A
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CORR, M;SLANETZ, AE;MARGULIES, DH
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MARGULIES, DH
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作者：
Zhu, De-Min;Dustin, Michael L.;Golan, David E.
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影响因子：
30.5
作者：
Huppa, JB;Gleimer, M;Davis, MM
通讯作者：
Davis, MM