TCR--PEPTIDE--MHC INTERACTION IN T CELL CROSSREACTIVITY

这一建议的目的是在分子水平上阐明T细胞受体(TCR)的交叉反应。开发的独特模型涉及免疫优势病毒多肽与两个非常密切相关的I类MHC变异体的交叉反应TCR识别。要研究的TCR共享相同的TCRbeta链，但一些人只看到其中一个复合体(单特异性识别)，而另一些人同时看到两个(交叉反应识别)。这表明TCRAlpha链必须在交叉反应中起决定性作用。TCR测序、单链TCR转基因(scTCRTg小鼠)的产生和分析、晶体结构测定和TCR突变将被用于剖析允许交叉反应的分子接触，这是一种潜在的同种异体反应、耐受诱导、移植排斥和自身免疫现象。目的：1.分析正常和scTCRTg小鼠交叉反应和单特异性CTL克隆的功能反应性和TCR序列，并建立定义密切相关TCR的交叉反应和单特异性TCR：肽：MHC相互作用的初步联系。2.确定单特异性和交叉反应性TCRs与合适的PEP：MHC络合物的X射线结构，并用定点突变对交叉反应识别进行确定性剖析。

The aim of this proposal is to elucidate T cell receptor (TCR) crossreactivity at the molecular level. The unique model developed involves crossreactive TCR recognition of the immunodominant viral peptide coupled to two very closely related class I MHC variants. TCRs to be studied share the same TCRbeta chains, but some see only one of the complexes (monospecific recognition) while others see both (crossreactive recognition). This indicates that the TCRalpha chain must play a decisive role in crossreactivity. TCR sequencing, generation and analysis of single TCR chain transgenic (scTCRTg mice), Crystal structure determination and TCR mutagenesis will be used to dissect the molecular contacts that permit crossreactivity, a phenomenon underlying alloreactivity, tolerance induction, transplant rejection and autoimmunity. The aims are: 1. To analyze functional reactivity and TCR sequence of crossreactive and monospecific CTL clones from normal and scTCRTg mice and establish the preliminary contacts that define crossreactive and monospecific TCR:peptide:MHC interactions for closely related TCRs. 2. To determine the x-ray structures of the monospecific and crossreactive TCRs with the appropriate pep:MHC complexes, and use site-directed mutagenesis to definitively dissect crossreactive recognition.