PEPTIDES IDENTIFIED FROM THE TYPE I DIABETES ASSOCIATED MHC CLASS I-H2-KD

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。 主要组织相容性复合体(MHC)结合的多肽决定了重要生物学结果的命运，如对外来入侵的细胞防御和免疫反应，或者在某些异常情况下对自身抗原的反应。对来自第I类和第II类MHC分子的自然加工多肽的详细分析揭示了某些一般特征，例如，由第I类MHC分子选择的自然加工多肽的长度通常限制在8-10-MERS，而由第II类MHC分子选择的自然加工多肽的长度更长，变化更大，通常在14-24聚体之间。更重要的是，对自然处理的多肽的详细分析解决了关于在密切相关的MHC分子中选择多肽的特异性的关键问题，这在以前涉及合成多肽文库的研究中并不明显。 在这一分析中，我们试图确定由I类MHC分子H-2Kd选择的多肽的性质和基序。我们选择H-2Kd是因为它可能在几个疾病领域发挥重要作用，包括：对病毒和细菌病原体的反应、自身免疫性糖尿病、肿瘤免疫学以及基于多肽的肿瘤疫苗的疗效。我们对H-2Kd筛选出的大量多肽的分析结果已经确定了多肽结合的基序。虽然自然选择的多肽有很大一部分是8到10个氨基酸的长度，但也有相当一部分的长度更长，有些长达18-MERS。结合研究表明，短肽结合亲和力较高，形成长寿期肽-MHC复合体时，长肽结合较弱，解离速度较快。修剪长肽不会改善结合相互作用，相反，延长9-聚体自然处理的表位并不会减少结合。最后，对较长多肽的结合方式进行了研究。这些实验结果表明，H-2Kd选择的天然加工多肽的长度从8-MERS到18-MERS？虽然大多数多肽是8-10个氨基酸，但也有相当一部分是10个氨基酸的长度。这些多肽的免疫学意义目前正在研究中。

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. The repertoire of peptides bound by major histocompatability complexes (MHC) determines the fate of important biological outcomes such as the cellular defense and immune responses to foreign invaders or in some aberrant cases reactivity to self antigens. Detailed analyses of naturally processed peptides from class I and II MHC molecules have revealed certain general features, for example the lengths of naturally processed peptides selected by class I MHC molecules are usually restricted to 8-10-mers whereas those selected by class II MHC molecules are longer and more variable, usually between 14-24-mer. More importantly, detailed analyses of naturally processed peptides have addressed key issues regarding the specificity of peptide-selection among closely related MHC molecules, which was not evident in prior studies involving synthetic peptide libraries. In this analyses, we sought to identify the nature and motif of peptides that are selected by the class I MHC molecule, H-2Kd. We selected H-2Kd because it may play a significant role in several areas of disease including: responses against viral and bacterial pathogens, autoimmune diabetes, tumor immunology, and the efficacy of peptide-based tumor vaccines. Results from our analyses of large numbers of peptides selected by H-2Kd have firmly established the peptide-binding motif. Although a large fraction of naturally selected peptides were 8 to 10 amino acids in length, there were a significant fraction that were of longer length, some as long as 18-mers. Binding studies demonstrated that while the short peptides bound with higher affinity and formed long-lived peptide-MHC complexes, the longer peptides bound weakly and had a fast dissociation rate. Trimming the long peptides did not improve binding interactions and conversely extending the 9-mer naturally processed epitopes did not decrease binding. Finally, the mode of binding of the longer peptides was investigated. Results from these experiments demonstrate that the Naturally processed peptides selected by H-2Kd varied in length from 8-mers to 18-mers ? although most peptides were 8-10 amino acids, there was a significant fraction that were 10 amino acids in length. The immunological significance of these peptides is currently under investigation.