REGULATORY MECHANISMS IN THE IMMUNE SYSTEM

这项研究计划的总体目标是了解 T细胞ab受体相互作用位点的亲和力/亲合力 对于常规肽抗原或超抗原（SAg）， 主要组织相容性复合体（MHC）II类分子以及 这种相互作用的质量会影响阳性T细胞的命运， 选择、负选择或生产性激活。 我们的实验 将在体外用重组可溶性蛋白进行。 我们将使用 突变研究，以详细确定三个相互作用的位点， 葡萄球菌SAg、SEA、SEC 3和TSST-1对小鼠V β 3、V β 8.2和 Vbeta 15分别。 此外，在生物传感器表面等离子体共振中， 研究中，我们将研究Va和MHC II类对 TCR V β与这些SAg结合的质量。 在另一组 在实验中，我们将从CD 4 + T细胞杂交瘤制备可溶性TCR 已知的抗原/MHC反应性来源于T细胞， 在携带单个II类MHC的转基因小鼠中阳性选择 分子与单个肽复合。 我们将用这些TCR来比较 正选择、负选择、负选择和负选择所需的亲和力/亲合力 选择和T细胞活化。 实验将直接涉及 可溶性TCR与MHC/肽复合物的结合研究，包括 具有限定几何形状的可溶性多价TCR的构建。 这些 实验将检验提出TCR亲和力决定TCR亲和力的假设， T细胞发育的命运

The overall goal of this research program is to understand the affinities/avidities of the sites of interaction on T cell ab receptors (TCRs) for conventional peptide antigens or superantigens (SAgs) bound to major histocompatibility complex (MHC) Class II molecules and how the quality of that interaction affects the fate of the T cell in positive selection, negative selection or productive activation. Our experiments will be performed in vitro with recombinant soluble proteins. We will use mutational studies to determine in detail the sites of interaction of three staphylococcal SAgs, SEA, SEC3 and TSST-1 on mouse Vbeta3, Vbeta8.2 and Vbeta15 respectively. In addition, in biosensor surface plasmon resonance studies we will examine the contribution from Va and MHC class II to the quality of TCR Vbeta binding to these SAgs. In a separate set of experiments, we will prepare soluble TCRs from CD4 plus T cell hybridomas of known antigen/MHC reactivity derived from T cells that have been positively selected in transgenic mice bearing a single MHC class II molecule complexed to a single peptide. We will use these TCRs to compare the affinities/avidities required for positive selection, negative selection and T cell activation. The experiments will involve direct binding studies of soluble TCRs to MHC/peptide complexes and include construction of soluble multivalent TCRs with defined geometries. These experiments will test hypotheses which propose that TCR affinity determines the fate of developing T cells.