PROTEOLYTIC GENERATION OF ANTIGENIC PEPTIDES

表达CD8的T细胞（TCD8+）在根除淋巴瘤中起关键作用。 细胞内寄生虫如病毒。 TCD8+识别MHC I类 与8至10个残基的肽形成复合物的分子， 位于胞质溶胶中的病毒蛋白质。 人们对 肽产生的机制。 有间接 证据表明蛋白酶体参与了抗原的产生， 缩氨酸 蛋白酶体是存在于大肠杆菌中的丰富的大分子结构。 细胞内的细胞质和细胞核具有多种蛋白酶活性。 它们被认为是负责能量依赖性蛋白水解 其中泛素在靶向蛋白质中起着重要作用， 杀伤性 尽管据信至少有一些蛋白水解 发生在细胞质中，目前还不确定最终的决定因素是否 在胞质溶胶中产生，或者是否发生额外的修剪 从胞质溶胶中转运后。 我们已经采取了几种方法来评估网站和性质， 在抗原肽的产生中利用的蛋白水解机制。 首先，我们生产了表达一种泛素形式的重组牛痘， 改变以干扰泛素靶向的蛋白水解。 二是 将I类分子的胞质形式改造成应该作为 用于检测细胞质中抗原肽存在的探针。

CD8 expressing T cells (TCD8+) play a critical role in eradicating intracellular parasites such as viruses. TCD8+ recognize MHC class I molecules in a complex with peptides of 8 to 10 residues derived from viral proteins located in the cytosol. There is tremendous interest in the mechanism by which peptides are generated. There is indirect evidence that implicates proteasomes in the generation of antigenic peptides. Proteasomes are abundant macromolecular structures present in the cytosol and nucleus in cells with multiple protease activities. They are thought to be responsible for the energy dependent proteolysis in which ubiquitin plays a prominent role in targeting proteins for destruction. Although it is believed that at least some proteolysis occurs in the cytosol, it is uncertain whether the ultimate determinants are generated in the cytosol, or whether additional trimming occurs following transport from the cytosol. We have initiated several approaches to assess the site and nature of proteolytic mechanisms utilized in the generation of antigenic peptides. First, we produced vaccinia recombinants expressing a form of ubiquitin altered to interfere with ubiquitin-targeted proteolysis. Second, we engineered a cytosolic form of class I molecule to that should serve as a probe for the presence of antigenic peptides in the cytosol.