T CELL ACTIVIATION BY DISTINCT ANTIGEN PRESENTING CELLS

人和实验动物对紫外线的照射 (紫外线)可导致免疫耐受。朗格汉斯细胞(LC)是 正常人优势抗原提呈细胞(APC) 表皮。暴露在紫外线下后，LC被渗透 巨噬细胞(UV-MPH)是表皮的主要APC。因为 这两种APC启动不同的免疫结果，我们 假设它们与T细胞的相互作用会有所不同。 使用新鲜的人类细胞呈现同种异体抗原，我们展示了几个 分歧是存在的。1)不同的共刺激分子表达： 与LC相比，UV-MPH表达更少的B7-1、B7-2和CD40，更多的LFA-1和 类似的ICAM-1、ICAM-3和LFA-3。2)不同的共刺激分子 用途：UV-MPH-，但不是LC刺激的T细胞生长是CD49e (α5整合素)依赖。3)独特的T细胞生长因子使用：In 与LC相比，UV-MPH刺激的T细胞增殖不依赖IL-2， IL-7和IL-15，并依赖IL-4。4)独特的激活基因 表达：与LC相比，UV-MPH刺激的T细胞缺乏 在表达IL-2Rpha的能力上，这对形成至关重要 高亲和力的IL-2受体。5)独特的细胞因子产生： 与LC相比，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。关于T的比较 这两个APC的细胞激活提供了一个模型系统，在该系统中 不同的信号被提供给T细胞，它们以不同的方式响应 礼貌。在本申请中，我建议在以下情况下调查 该领域公认专家的指导，信号转导 调节T细胞活化的不同结果的事件 二、体内来源的人APC。具体地说，使用电子迁移率 移位分析、超移位分析、激酶分析、免疫沉淀和 蛋白质印迹分析I将阐明允许紫外线-mph的途径。 在IL-2缺乏的情况下激活T细胞生长和IL-2的表达 2Rpha的表达。推测的机制包括减少的核因子-kappaB2 表达(由于CD28信号减少)和增强的AP-1或NF-AT 表达(由于VLA-5信号增加)。信令通过 VLA-5被认为是通过受体酪氨酸激酶转导的， 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.