Biophysics Institute, Johannes-Kepler-University Linz, Linz, Austria.
Biophys J. 2012 Jul 18;103(2):L17-9. doi: 10.1016/j.bpj.2012.06.019. Epub 2012 Jul 17.
The binding of peptide-loaded major histocompatibility complex (pMHC) to the T cell receptor (TCR) represents the central step in T cell antigen recognition. It proceeds in the cell contact area between a T cell and an antigen-presenting cell termed the immunological synapse. An important and unresolved issue is how T cells discriminate between potentially harmful and harmless antigens. One limitation has been the difficulty to measure interaction parameters directly, that is, as they occur in the immunological synapse. Here we present a single-molecule approach to determine pMHC-TCR interaction kinetics in situ based on diffusion analysis of dye-labeled pMHC. We find synaptic off-rates >10-fold accelerated when compared to the dissociation of purified proteins measured in vitro.
肽负载的主要组织相容性复合体 (pMHC) 与 T 细胞受体 (TCR) 的结合代表了 T 细胞抗原识别的中心步骤。它发生在 T 细胞和抗原呈递细胞之间的细胞接触区域，称为免疫突触。一个重要且未解决的问题是 T 细胞如何区分潜在的有害和无害抗原。一个限制因素一直是难以直接测量相互作用参数，即它们在免疫突触中发生的情况。在这里，我们提出了一种基于荧光标记的 pMHC 扩散分析的单分子方法，用于原位确定 pMHC-TCR 相互作用动力学。我们发现，与体外测量的纯化蛋白的解离相比，突触的离解速率加快了 10 多倍。
