Structure/biology of short-lived MHC II-ligand complexes

在上一个资助周期中，我们表征了抗原肽与MHC II类分子结合的动力学中间体。这些中间配合物具有亲和力低、缔合和解离速度快的特点；它们代表肽受体形式，在转化为稳定的复合物之前需要发生构象变化。中间复合物可以被流感HA 306-318肽的变体（P1结合残基的变化）和P1口袋中突变的HLA-DR1分子模拟。在下一个周期，我们建议研究这些短寿命中间复合物的生物学，解决三个目标：1。表征体外T细胞对短寿命复合物的反应，预计是能量诱导。2. 确定负责能量感应3a的apc。比较DO-/-、DM-/-和WT胸腺基质细胞3b的肽谱。产生表达参与短寿命复合物的DR1突变体（DRbG86Y）的小鼠，并研究胸腺细胞选择。

During the last grant cycle, we have characterized a kinetic intermediate in the binding of antigenic peptides to MHC class II molecules. These intermediate complexes are characterized by low affinity and fast association and disassociation rates; they represent peptide-receptive forms, and require a conformational change to occur before converting to stable complexes. The intermediate complexes can be mimicked by variant of flu HA 306-318 peptide (changes to P1-binding residues) and by an HLA-DR1 molecule mutated in the P1 pocket. During the next cycle, we propose to study the biology of these short-lived intermediate complexes, addressing three aims: 1. Characterization of in vitro T cell responses to short-lived complexes, expected to be anergy induction. 2. Identify APCs responsible for anergy induction 3a. Compare peptide repertoires of DO-/-, DM-/- and WT thymic stromal cells 3b. Generate mice expressing a DR1 mutant (DRbG86Y) that participates in short-lived complexes and study thymocyte selection.