FUNCTIONAL TCR ANALYSIS OF SIV SPECIFIC CTL

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们已经完成了识别免疫过程中出现的优势和次要SIV-CTL表位的TCR谱系和功能进化的研究。 我们证明了疫苗诱导的表位特异性CD8T淋巴细胞具有与SHIV-89.6P感染相当的克隆性多样性，并且这些克隆性CD8T淋巴细胞群可以持续存在。此外，在接种的猕猴队列中，在接种了DNA/rMVA的猴子和接种了Rad的猴子中，CD8T淋巴细胞表位特异性的克隆组成几乎相同。 我们还完成了研究CTL免疫优势机制的第一部分。我们的数据表明，在我们的实验系统中，肽结合亲和力、抗原提呈或加工的效率以及T细胞功能差异不太可能是导致免疫优势的机制。然而，对TCR谱系的分析表明，占主导地位的p11C特异性CTL群体使用了更多数量的TCR克隆。特定TCR的优先使用和体外功能TCR-α和-β链配对试验表明，每个肽/MHC复合体可能只能被有限数量的唯一的α和β链对组合识别。主要的p11C特异性CTL群体使用的TCR克隆的较大阵列可能是由于产生这些特定TCR链对的可能性较高所解释的。因此，这些数据表明，抗原特异性的NA-VE T细胞前体频率可能是预先确定的，这决定了SIV特异性CD8 T细胞反应的免疫优势。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have completed the study to characterize the TCR repertoire and the functional evolution of TCRs that recognize dominant and subdominant SIV-CTL epitopes that arise during immunization. We demonstrated that vaccine-elicited epitope-specific CD8+ T lymphocytes have a clonal diversity comparable to that induced by SHIV-89.6P infection, and these clonal CD8+ T lymphocyte populations can persist. Moreover, in the vaccinated monkey cohort, the clonal make-up of an epitope-specific CD8+ T lymphocyte population was almost identical in monkeys vaccinated with plasmid DNA/rMVA and in monkeys following vaccination with rAd. We have also completed the first part of the study to investigate the mechanism of CTL immunodominance. Our data suggest that in our experimental system the peptide binding affinity, efficiency of Ag presentation or processing and T cell functional differences are not likely to be the mechanism responsible for immunodominance. However, the analysis of the TCR repertoire revealed the usage of higher numbers of TCR clones by the dominant p11C-specific CTL population. Preferential usage of specific TCRs and the in vitro functional TCR-alpha and -beta chain-pairing assay suggests that every peptide/MHC complex may only be recognized by a limited number of unique combinations of alpha and beta chain pairs. The wider array of TCR clones used by the dominant p11C-specific CTL population might be explained by the higher probability of generating those specific TCR chain pairs. Thus these data suggest that Ag-specific na¿ve T cell precursor frequency may be predetermined and that this dictates immunodominance of SIV-specific CD8+ T cell responses.