2015-08-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/656050摘要：異位性皮膚炎是一種常見的慢性發炎性皮膚疾病，異位性疾病的過敏原皆為環境中普遍存在的蛋白質抗原。蛋白質抗原經皮致敏已知為異位性皮膚炎重要的致敏途徑之ㄧ。我們和其他學者利用小鼠貼膚模型，證實連續性蛋白質抗原經皮致敏，在 BALB/c和 C57BL6小鼠，均引發顯著的 Th2型反應，少量的 Th17和微弱的 Th1反應。最近我們建立非連續性蛋白質抗原貼膚模型，發現在 BALB/c小鼠仍引發顯著的 Th2反應，但在 C57BL/6小鼠則引發強烈的 Th1和 Th2反應。 調控Th分化的控制因子中，樹突狀細胞(DC)一直被認為具有最關鍵的角色。已知DC 有許多亞型，在局部淋巴結內，除了plasmacytoid DC (pDC)外，有resident DCs (包括 CD4+DC，CD8+DC，double negative DC) 和migratory DC 。在皮膚內，migratory DC又有三種亞型(Langerhans cell，langerin+ dermal DC和langerin- dermal DC)。有許多報告支持這些不同的migratory DC 亞型，對Th分化有特定的作用，但這些利用不同模型和方法得到的結果，常是不一致的。 在實驗小鼠中，BALB/c和C57BL/6 小鼠分別易引發Th2 和Th1 的反應。根據我們的初步實驗結果，在蛋白質抗原經皮致敏中，是因為BALB/c小鼠的langerin+ dermal DCs，捕捉到的抗原較B6小鼠為少，故只引發Th2反應，無法引發Th1反應。下述是我們的假說: 1. 各種migratory DC亞型具有不同抗原捕捉能力，而C57BL/6 小鼠的優於BALB/c小鼠。2. 各種migratory DC亞型的成熟度，決定其抗原呈獻能力，其中langerin- dDC最佳。3. 各種migratory DC亞型具有不同的Th1/Th2引發能力，而langerin- dDC最易引發Th1 反應。4. 各種migratory DC捕捉的抗原量和抗原呈獻能力共同決定引發的Th1/Th2 反應。我們將利用生物內螢光抗原給予、皮膚培養、流式細胞儀分析，T細胞增生試驗、細胞素測量等方法來完成下列兩項特定目標 特定目標一: 探討各種皮膚樹突狀細胞亞型的抗原捕捉能力 特定目標二: 探討各種皮膚樹突狀細胞亞型的抗原呈獻能力 我們長期致力於”異位性皮膚炎致病機轉”的研究，尤其著重於”蛋白質抗原經皮致敏的機制”，此研究為長期研究的一部分。我們預期此研究計畫的成果，將幫助我們了解各種皮膚的 migratory DC 亞型。也幫助我們了解異位性體質者和非異位性體質者在蛋白質抗原經皮致敏中引發不同的 Th1/Th2反應的原因。而且，本研究的成果將有助於異位性疾病過敏原經皮致敏的預防，以及蛋白質過敏原疫苗的研發。<br> Abstract: Atopic dermatitis is a common chronic cutaneous inflammatory disease. The allergens of atopic disease are proteins universally present in environment. Epicutaneous sensitization with proteins allergen has been proven to be one of the most important routes for sensitization. We and other researchers have established a murine protein-patch model and demonstrated that repeated epicutaneous sensitization with protein antigen induces a predominant Th2, a modest Th17 and a weak Th1 responses in both BALB/c and B6 mice. Recently, we set up a non-repeated protein-patch model and found that non-repeated epicutaneous exposure of protein antigen also induces a predominant Th2 response in BALB/c mice but induces strong Th1 and Th2 responses in C57BL/6 mice. Dendritic cells (DC) play a critical role in Th differentiation. Many DC subsets have been recognized. In lymph nodes, besides plasmacytoid DC (PDC), there are lymphoid tissue-resident DCs (CD4+ DC, CD8+ DC, double negative DC) and migratory DCs. In cutaneous lymph nodes, the migratory DC includes three subsets: Langerhans cell, langerin+ dermal DC, langerin- dermal DC. Many studies support the notions that different migratory DC subset has functional specialization for Th differentiation. However, using different models and methods, the researchers usually got conflict results. BALB/c and C57BL/6 mice are prone to develop Th2 and Th1 responses, respectively. Based on our preliminary results, it shows that inability of migratory langerin+ dermal DCs to capture enough antigen for presentation resulted in marginal Th1 response in BALB/c mice. The followings are our hypotheses. First, each migratory DC subset has differential intrinsic capability in Ag capture, with C57BL/6 mice better than BALB/c mice. Second, each migratory DC subset has differential maturation status which determines its capability in Ag presentation, with langerin- dDC being the best. Third, each migratory DC subset has its intrinsic capability in induction of Th1/Th2 response, with langerin- dDC inducing highest Th1 response. Fourth, the magnitude of Th1/Th2 responses depends on the amount of captured Ag and the intrinsic capability of Ag presentation and induction of Th1/Th2 responses of each DC subset. We will perform fluorescent Ag administration, skin explant culture, flow cytometric analysis, T cell proliferation assay and measurements of cytokine contents to achieve the following specific aims. Specific aim 1: Explore the capability of antigen capture of cutaneous migratory DC subsets Specific aim 2: Explore the capability of antigen presentation of cutaneous migratory DC subsets We have been devoted to studying “the pathogenesis of atopic dermatitis” for a long time, especially focusing on “mechanisms of epicutaneous sensitization”. This project is one part of the longterm efforts. We anticipate that the results obtained from this project will improve our understanding of the cutaneous migratory DC subset. We also anticipate the experimental results could contribute to the understanding of differential Th1/Th2 responses induced in human atopy and non-atopy. Moreover, the information from this study will provide great help for prevention of epicutaneous sensitization with environmental allergens as well as for developing vaccines for atopic diseases.樹突狀細胞亞型抗原呈獻抗原捕捉dendritic cell subsetsantigen captureantigen presentation