T CELL ACTIVIATION BY DISTINCT ANTIGEN PRESENTING CELLS

人类和实验动物暴露于紫外线照射 (UV)会导致免疫耐受 朗格汉斯细胞（LC）是 未照射的正常人的优势抗原呈递细胞（APC） 表皮 暴露于UV后，LC被渗透取代， 巨噬细胞（UV-Mph）为表皮的优势APC。 因为 不同的免疫结果是由这两个APC启动的，我们 假设它们与T细胞的相互作用会有所不同。 使用新鲜人细胞的同种抗原呈递，我们显示了几个 存在差异。 1)独特的共刺激分子表达： 相对于LC，UV-Mph表达较少的B7-1、B7-2和CD 40，表达较多的LFA-1， 比较ICAM-1、ICAM-3和LFA-3。 2)独特的共刺激分子 利用率：UV-Mph刺激的T细胞生长是CD 49 e，而LC刺激的T细胞生长不是CD 49 e （α 5整联蛋白）依赖性。 3)特异性T细胞生长因子用途：在 与LC相反，UV-Mph刺激的T细胞生长不依赖于IL-2， IL-7和IL-15，并依赖于IL-4。4)独特激活基因 表达：与LC-相反，UV-Mph-刺激的T细胞缺乏 表达IL-2 R α的能力，这对形成 高亲和力IL-2受体。 5)独特的细胞因子产生： 与LC-相反，UV-Mph-刺激的T细胞产生IL-4和IL-5， 与免疫耐受相关的细胞因子。 T的比较 通过这两种APC的细胞活化提供了模型系统，其中 不同的信号被提供给T细胞，T细胞以不同的方式应答。 礼节. 在本申请中，本人建议根据 在该领域公认的专家的指导下， 这些事件介导T细胞活化的不同结果， 二是体内衍生的人APC。 具体来说，利用电动汽车 位移测定、超位移测定、激酶测定、免疫沉淀和 蛋白质印迹分析I将阐明UV-Mph 激活T细胞的生长和IL-2的表达，尽管缺乏IL- 2 R α表达。 假定的机制包括减少NF-κ B2 表达（由于CD 28信号减少），AP-1或NF-AT增强 表达（由于VLA-5信号增加）。 信令通过 假设VLA-5通过受体酪氨酸激酶转导， MAP激酶途径。

Exposure of humans and experimental animals to ultraviolet irradiation (UV) can lead to immunologic tolerance. Langerhans cells (LC) are the predominant antigen presenting cell (APC) of normal unirradiated epidermis. After exposure to UV, LC are replaced by infiltrating macrophages (UV-Mph) as the dominant APC of epidermis. Because different immune outcomes are initiated by these two APC, we hypothesized that their interactions with T cells would be different. Using alloantigen presentation with fresh human cells, we show several differences exist. 1) Distinct costimulatory molecule expression: Relative to LC, UV-Mph express less B7-1, B7-2 and CD40, more LFA-1, and comparable ICAM-1, ICAM-3 and LFA-3. 2) Distinct costimulatory molecule utilization: UV-Mph-, but not LC-stimulated T cell growth is CD49e (alpha5 integrin)-dependent. 3) Distinct T cell growth factor use: In contrast to LC-, UV-Mph-stimulated T cell growth is independent of IL-2, IL-7, and IL-15 and dependent on IL-4. 4) Distinct activation gene expression: In contrast to LC-, UV-Mph-stimulated T cells are deficient in their ability to express IL-2Ralpha, which is critical to formation of the high affinity IL-2 receptor. 5) Distinct cytokine production: In contrast to LC-, UV-Mph-stimulated T cells produce IL-4 and IL-5, cytokines associated with immunologic tolerance. The comparison of T cell activation by these two APC provides a model system in which distinct signals are provided to T cells, which respond in distinct manners. In the present application, I propose to investigate, under the guidance of recognized experts in the field, the signal transduction events that mediate the different outcomes of T cell activation by these two, in vivo-derived human APC. Specifically, using electromobility shift assays, supershift assays, kinase assays, immunoprecipitation and western blot analysis I will elucidate the pathways that allow UV-Mph to activate T cell growth and IL-2 expression despite deficient IL- 2Ralpha expression. Postulated mechanisms include reduced NF-kappaB2 expression (because of reduced CD28 signals), and enhanced AP-1 or NF-AT expression (because of increased VLA-5 signals). Signaling through VLA-5 is hypothesized to be transduced via the receptor tyrosine kinase, MAP kinase pathway.