CD40-CD154 Interactions in Cryptosporidial Immunity

描述(申请人提供)：微小隐孢子虫(CP)病因 携带艾滋病或CD154基因突变(X)的人的长期和严重感染 连锁免疫缺陷伴高免疫球蛋白M，或XHIM)导致硬化 胆管炎和肝功能衰竭。CP感染肠道上皮细胞，正常情况下 结束其寿命被固有层中的树突状细胞(DC)吞噬。这个 支持这一应用的假设是，CD40信号对于 CP将被DC‘杀死。这一假说预测，完整、可行的CP将 无CD40-CD154信号时到达肠系膜淋巴结(MLN)。这个 潜在的假说解释了CD4T细胞表达 CD154和骨髓来源的CD40+细胞用于小鼠从CP中恢复 感染。这就提出了一个问题：CD154+CD4+T细胞是否需要清除 CP必须是CP特定的吗？我们发现表达转基因T细胞的RAG-/-小鼠 卵清蛋白(或细胞色素c)的细胞受体(TG)可从CP感染中恢复。 我们的初步数据将显示，过继转移的DO11.10 T细胞 在感染CP的RAG-/-小鼠的MLN中激活，前提是它们处于 MHC与环境相匹配。我们的具体目标一将决定E 约xAI3转基因小鼠可清除肺炎衣原体感染。此方法测试 假设抗原肽在自身MHC上的负载是 CP感染需要从肠道清除。目标1下的次要方法将 (A)验证这样的假设：转基因的CD4细胞仅在 他们被选中的MHC环境。在《信用证》中， IL-12、B7和CD28对TG和野生型CD4细胞的激活作用 比较一下。具体目标二将检验固有层DC的假设 需要CD40信号才能降解内吞的蛋白质和核酸 CP和上皮细胞。之所以选择这些目标，是因为它们解决了问题 对CP的免疫和免疫病理学的了解至关重要 结果当一种感染没有被根除时。在CP中建立的机制 感染很可能与其他重要的细胞内感染有关 病原体，特别是微孢子虫和弓形虫。结果将是 对慢性感染这种寄生虫的免疫缺陷人群很重要。

DESCRIPTION (Provided by the applicant): Cryptosporidium parvum (CP) causes prolonged and severe infections in humans with AIDS or mutated CD154 genes (X linked immunodeficiency with hyper IgM, or XHIM) leading to sclerosing cholangitis and liver failure. CP infects gut epithelial cells that normally end their lifespan engulfed by dendritic cells (DC) in the lamina propria. The hypothesis underlying this application is that 'a CD40 signal is necessary for CP to be killed by DC'. This hypothesis predicts that intact, viable, CP will reach the mesenteric lymph node (MLN) when there is no CD40-CD154 signal. The underlying hypothesis accounts for the requirement for CD4 T cells that express CD 154, and marrow-derived CD40+ cells, for mice to recover from a CP infection. It raises the question: do the CD154+ CD4+ T cells required to clear CP have to be CP-specific? We found that RAG-/- mice expressing transgenic T cell receptors (Tg) for ovalbumin (or cytochrome c) recover from CP infections. Our preliminary data will show that adoptively transferred DO11.10 T cells are activated in the MLN of CP-infected RAG-/- mice provided that they are in an MHC matched environment. Our Specific aim one will determine whether E aboutxAI3 transgenic mice can clear a CP infection. This approach tests the hypothesis that the loading of antigen peptides onto self-MHC is required for a CP infection to be cleared from the gut. Secondary approaches under Aim 1 will (a) test the hypothesis that transgenic CD4 cells clear CP infections only in the MHC environment in which they were selected. In lc the requirements for IL-12, B7 and CD28 for activation of Tg and wild type CD4 cells will be compared. Specific Aim two will test the hypothesis that lamina propria DCs require a CD40 signal to degrade the proteins and nucleic acids of endocytosed CP and epithelial cells. These aims are selected because they address issues critical for under- standing immunity to CP and the immunopathology that results when an infection is not eradicated. Mechanisms established in CP infections are likely to be relevant to other important intracellular pathogens, particularly Microsporidia and Toxoplasmah sp. The results will be important for immunodeficient humans chronically infected with the parasite.