PROPERTIES AND FUNCTION OF TLA AND CD1 IN THE GUT

胸腺白血病抗原（TLa）和CD 1是小鼠非经典类 肠上皮细胞上表达的I类分子。的 这些分子的功能是未知的，细胞介导的免疫 针对TLa或小鼠CD 1的应答尚未报道。 然而，考虑到它们的位置，TLa和CD 1可能 将肽呈递给肠上皮内淋巴细胞（IEL）。基于 根据我们的初步数据，我们进一步假设，这些非经典 I类分子可以在内质网外获得肽 它们已经进化到呈现肠内的肽， 在诸如内体或吞噬溶酶体的位点复制的病原体。 更好地了解TLa和CDI的功能及其可能的作用 在粘膜免疫应答中，将进行实验以比较 这些分子对经典I类蛋白质的行为。细胞 将进行粘附和结合测定以确定TLa和 CDI可以与CD 8相互作用，CD 8是大多数IEL表达的辅助受体 在小肠里。我们还将确定TLA和CDI是否需要 β 2微球蛋白的表达。结合肽 表达这些分子的转染细胞将被洗脱， 测序以确定是否存在所需的锚基序。因为两 这些非经典的I类分子在RMA-S中稳定表达 缺乏肽抗原转运蛋白的细胞，细胞运输研究 以确定在何处可以获得肽。这些 因此，实验将确定TLa和CDI是否具有抗原 提呈功能，以及它们所提呈的抗原类型。 从这些研究中获得的结果可以应用于研究 研究TLa和CDI的可能的体内功能。我们将重点 在三个方面。首先，我们将确定肽的HPLC图谱 从肠上皮细胞表达的TLa和CDI洗脱， 确定与转染子相比是否存在重大差异。 第二，使用在所有组织上表达TLa的转基因小鼠， 将尝试培养限制性T细胞系。对这些路线的研究 可以直接确定TLa对抗原呈递的要求。 第三，IEL识别由TLa和CDI结合的肽的能力将降低IEL识别TLa和CDI结合的肽的能力。 下定决心。这些研究应该提供重要的见解， 肠道中的抗原呈递功能，这可以提供进一步的 深入了解口服耐受诱导和粘膜免疫功能障碍， 比如炎症性肠病

The thymus leukemia antigen (TLa) and CD1 are mouse, nonclassical class I molecules that are expressed on intestinal epithelial cells. The function of these molecules is unknown, and a cell-mediated immune responses directed to either TLa or mouse CD1 have not been reported. However, on account of their location, it is possible that TLa and CD1 present peptide to intestinal intraepithelial lymphocytes (IEL). Based upon our preliminary data, we further hypothesize that these nonclassical class I molecules can acquire peptide outside of the endoplasmic reticulum, and that they have evolved to present peptides from intestinal pathogens that replicate in sites such as endosomes or phagolysosomes. To better understand the function of TLa and CDI, and their possible role in the mucosal immune response, experiments will be performed to compare the behavior of these molecules to classical class I proteins. Cell adhesion and binding assays will be carried out to determine if TLa and CDI can interact with CD8, a co-receptor which is expressed by most IEL in the small intestine. We will also determine if TLa and CDI require beta2microglobulin for their surface expression. Peptides bound by transfected cells that express these molecules will be eluted and sequenced to determine if there is a required anchor motif. Because both of these nonclassical class I molecules are stably expressed in RMA-S cells that lack peptide antigen transporter, cell trafficking studies will be performed to determine where peptide may be acquired. These experiments therefore will determine if TLa and CDI have antigen presenting function, and the types of antigens that they present. The results obtained from these studies can then be applied to studies investigating the possible in vivo function of TLa and CDI. We will focus on three areas. First, we will determine the HPLC profile of peptides eluted from TLa and CDI expressed by intestinal epithelial cells, to determine if there are major differences compared with the transfectants. Second, using transgenic mice that express TLa on all their tissues, we will attempt to raise TLa-restricted T-cell lines. Studies on these lines can determine directly the requirements for antigen presentation by TLa. Third, the ability of IEL to recognize peptides bound by TLa and CDI will be determined. These studies should provide important insights into antigen presentation function in the gut, which may provide further insight into oral tolerance induction and mucosal immune dysfunction such as in inflammatory bowel disease.