GENERATING ANTIGENIC PEPTIDE/MHC BY CRYPTIC TRANSLATION

该项目的长期目标是了解抗原加工机制如何通过非常规（神秘）翻译产生抗原肽/MHC I类复合物。最近几个不同实验室的研究表明，肿瘤、病毒感染细胞和转染细胞表面的MHC I类分子呈递的天然加工肽可能来自预期不被翻译的信使RNA区域。 细胞对抗原肽的这种隐蔽来源与代表蛋白质周转副产物的常规来源进行采样的机制尚不清楚。此外，在何种程度上，这些隐蔽肽有助于不同的肽库提出的MHC分子和他们的免疫学作用仍有待建立。在这项提案中，我们将测试的假设，这些非常规的，隐蔽的肽可能是一种新的翻译机制的产品，并可能在正常动物中发挥重要的免疫作用。 使用本实验室建立的独特试剂和方法，这些假设将通过以下方式进行检验：（1）定义确定mRNA的隐蔽翻译如何发生并导致肽/MHC I类复合物表达的上下文规则，（2）确定隐蔽肽/MHC I类复合物在正常转基因小鼠中的免疫学作用，以及，（3）分析产生隐蔽肽/MHC I类复合物的途径中的不同步骤。人们期望，提高对隐蔽肽/MHC复合物产生机制的理解，不仅将提供新的抗原肽来源和疫苗设计方法，而且还将产生对蛋白质翻译和免疫监测机制的新见解。

The long term goal of this project is to understand how the antigen processing mechanism generates antigenic peptide/MHC class I complexes by unconventional (cryptic) translation. Recent studies, from several different laboratories have demonstrated that naturally processed peptides presented by MHC class I molecules on the surface of tumors, virally infected cells, and transfected cells can arise from regions of messenger RNA that were not expected to be translated. The mechanism by which cells sample this cryptic source of antigenic peptides versus the conventional source representing by-products of protein turn-over is not known. In addition, to what extent these cryptic peptides contribute to the diverse pool of peptides presented by MHC molecules and their immunological role remains to be established. In this proposal we will test the hypotheses that these unconventional, cryptic peptides could be products of a novel translational mechanism and could play a significant immunological role in normal animals. Using unique reagents and methods established in this laboratory these hypotheses will be tested by, (1) defining the context rules which determine how cryptic translation of the mRNA occurs and results in expression of peptide/MHC class I complexes, (2) determining the immunological role of cryptic peptide/MHC class I complexes in normal transgenic mice, and, (3) analyzing the different steps in the pathway for generation of cryptic peptide/MHC class I complexes. It is expected that improved understanding of the mechanism for generation of cryptic peptide/MHC complexes will not only provide novel sources of antigenic peptides and approaches to vaccine design but will also yield new insights into protein translation and immunesurveillance mechanisms.