IMMUNOREGULATORY FUNCTIONS OF TCR AND MHC COMPLEXES

描述(改编自调查者摘要)： 主要组织相容性复合体(MHC)抗原及其同源配体， T细胞受体(TCR)在免疫调节中起着核心作用 回应。使用在以前项目期间开发的系统，我们将 分析TCR与MHC分子、抗原/MHC复合体的相互作用 表达，以及免疫调节的新治疗方法。而当 结构研究有助于阐明TCR和MHC之间的相互作用 分子，简并TCR识别的基础还没有被 回答。这个问题对理解分子模仿很重要，一个 自身免疫和同种异体反应的模型，以及亲和力有多低 相互作用，如肽/MHC拮抗剂和正选择， 刺激T细胞。我们将在以下方面使用变化：交联型图案； 本征和本征荧光；荧光能量转移；以及 用蛋白酶敏感性研究TCR/MHC界面的结构特征 和TCR信令。识别和追踪抗原/MHC复合体的能力 由于缺乏高亲和力的特异性试剂而受到阻碍。可溶的 我们最近开发的TCR的二价版本具有很高的 多肽/MHC复合体的亲和力和特异性。我们将使用这些 分子来识别参与正选择的多肽。我们还将 用二价TCR分析淋巴因子、GM-CSF、干扰素-γ、 和肿瘤坏死因子-α对抗原体外加工和体内表达的影响 交叉拼写。MHC和TCR分子的可溶二价版本也有 在体外和体内的潜在免疫调节应用。我们的 早期研究表明，可溶性二价MHC抑制同种异体反应性T细胞 体外激活。在最后一个项目期间，我们延长了这些 发现并显示可溶的二价MHC抑制同种异体移植排斥反应。 在接下来的几年里，我们将进一步描述 可溶性二价MHC分子在同种异体反应和抗原特异性上的作用 免疫反应。我们还将观察可溶性二价TCR/Ig是否能够调节 免疫反应。我们已经生产出了二价、高亲和力的可溶类似物 特异性免疫反应的大部分成分。为了进一步 增加有效亲和力，我们就会得到可溶的多价络合物 TCR和MHC分子。更有效地重述TCR 结合复合体，我们将CD8辅助分子结合到可溶性 TCR类似物。加深对MHC和TCR相互作用的理解 分子将提高我们对它们在生物多样性产生中的作用的理解 包括正常免疫反应和病理免疫反应。可溶性二价MHC和TCR 类似物也提出了潜在的基于免疫的新治疗策略。

DESCRIPTION (Adapted from Investigator's abstract): The interaction of major histocompatibility complex (MHC) antigens, and their cognate ligands, the T-cell receptor (TCR), plays a central role in the regulation of immune responses. Using systems developed during previous project periods, we will analyze the interactions of TCR and MHC molecules, antigen/MHC complex expression, and new therapeutic approaches to immunomodulation. While structural studies helped elucidate the interaction between TCR and MHC molecules, the basis of degenerate TCR recognition has not yet been answered. This question is important in understanding molecular mimicry, a model of autoimmune and alloreactive responses, and how low affinity interactions, such as peptide/MHC antagonists and positive selection, stimulate T-cells. We will use changes in: crosslinking patterns; extrinsic and intrinsic fluorescence; fluorescence energy transfer; and protease sensitivity to study structural aspects of the TCR/MHC interface and TCR signaling. The ability to identify and track antigen/MHC complexes has been hampered by the lack of high affinity specific reagents. Soluble divalent versions of TCR, which we have recently developed, have high affinity and specificity for peptide/MHC complexes. We will use these molecules to identify peptides involved in positive selection. We will also use divalent TCR to analyze the influence of lymphokines, GM-CSF, IFN-gamma, and TNF-alpha on antigen processing in vitro and expression in vivo during crosspriming. Soluble divalent versions of MHC and TCR molecules also have potential immunomodulatory application both in vitro and in vivo. Our earlier work showed that soluble divalent MHC inhibits alloreactive T-cell activation in vitro. During this last project period we have extended these finding and shown that soluble divalent MHC inhibits allograft rejection. Over the next several years we will further characterize the effects of soluble divalent MHC molecules on both alloreactive and antigen-specific immune responses. We will also see if soluble divalent TCR/Ig can modulate immune responses. We have produced divalent, high affinity soluble analogs of most of the components of the specific immune responses. To further increase the effective affinity, we will make soluble multivalent complexes of both TCR and MHC molecules. To more effectively recapitulate the TCR binding complex, we will incorporate the CD8 accessory molecule into soluble TCR analogs. An enhanced understanding of the interactions of MHC and TCR molecules will improve our understanding of their role in the generation of both normal and pathological immune responses. Soluble divalent MHC and TCR analogs also suggest potential novel immune-based therapeutic strategies.