Identification and characterization of cellular mechanisms which selectively cont

描述(申请人提供)：细胞毒性CD8+T细胞是体内的防御性细胞，负责清除感染了细胞内微生物(如病毒)的自身细胞。为了防止清除其他健康细胞，细胞毒性T细胞必须首先识别与MHC I类分子结合的疾病特异性蛋白片段，该片段将显示在患病细胞的表面。虽然多肽片段可能是由于蛋白质在细胞内的自然周转而产生的，但在诱导蛋白质抗原合成后，可以迅速在细胞表面检测到多肽-MHC复合体。这导致了有缺陷的核糖体产物(或水滴)假说，该假说认为新合成的蛋白质的子集将有缺陷，并立即在细胞内降解。这项工作将检验这一假设，即细胞具有生成蛋白质抗原的特定机制，并将使用一种新描述的方法，将抗原肽的来源分离为真正的液滴和来自蛋白质自然周转的多肽。这项检测已经鉴定了几种可以选择性地消除滴状抗原提呈的化学物质和基因产品。这些靶点将是识别细胞机制(S)的起点，该机制控制滴液如何产生和靶向抗原递呈。细胞的泛素结合和移除元件将被特别监测，因为它们与抗原提呈有关。这项工作的结果将对疫苗和疗法的开发具有重要意义，这些疫苗和疗法旨在引发对各种疾病的细胞毒性T细胞反应。

DESCRIPTION (provided by applicant): Cytotoxic CD8+ T cells are defensive cells within the body that are responsible for eliminating self cells that have become infected with an intracellular microbe, such as a virus. To prevent elimination of otherwise healthy cells, cytotoxic T cells must first recognize a fragment of the disease-specific protein bound to an MHC class I molecule, which will be displayed on the surface of the diseased cell. While the peptide fragments may be derived due to the natural turnover of proteins within the cell, peptide-MHC complexes can be detected on the cell surface rapidly after the induction of protein antigen synthesis. This has led to the defective ribosomal product (or DRiP) hypothesis which states that a subset of newly synthesized protein will be defective and immediately degraded within the cell. This work will test the hypothesis that cells have a specific mechanism for generating protein antigens and will use a newly described assay that can segregate the sources of antigenic peptides into true DRiPs and peptides derived from the natural turnover of proteins. This assay has already indentified several chemicals and gene products which can selectively eliminate DRiP antigen presentation. These targets will be the starting point to identify the cellular mechanism(s) that govern how DRiPs are generated and targeted for antigen presentation. The ubiquitin conjugation and removal elements of the cell will be specifically monitored as they have been implicated in antigen presentation. The results of this work will have important implications for the development of vaccines and therapies that are designed to elicit cytotoxic T cell responses to a variety of diseases.