Antigen Processing And Presentation In The Intestine

抗原在肠道中的加工和呈现

• 批准号: 6808978
• 负责人: BRIAN KELSALL
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6808978
• 关键词: MHC class I antigen; MHC class II antigen; Peyer's patches; T lymphocyte; antigen presentation; cell differentiation; chemokine; cholera toxin; cytokine; dendritic cells; enzyme linked immunosorbent assay; flow cytometry; interleukin 10; intestines; laboratory mouse; method development; mucosal immunity; oral tolerance; polymerase chain reaction

This project focuses on how antigens are processed in the intestine of mice. While it is clear that the outcome of oral antigen exposure can be either positive, i.e., the development of mucosal IgA responses, and in some cases the induction of systemic immunity as well, or negative, i.e., the induction of oral tolerance, the details of why one or the other outcome occurs is complex and poorly understood. While it is known that the antigen formulation, the presence of adjuvants, and the antigen dose, as well as genetic factors, can affect mucosal immune responses, how these act to influence immunity has never been established. In prior studies we have established the presence of different antigen-presenting cell populations in the Peyer's patch (PP) and lamina propria and have detailed the surface phenotype, function, and migration of DCs in the PP using in situ immunofluorecense microscopy and in situ hybridization, flow cytometry of purified cells, and in vitro assays of cytokine production (ELISA and quantitative RT-PCR) and T cell differentiation. We determined that there are 3 separate subpopulations of immature DCs in the PP, lymphoid (CD8+), myeloid (CD11b+), and double negative (DN) Dcs that express neither CD8 or CD11b. These separated DC subpopulations are located in distinct sites in the PP, and are capable of inducing the differentiaion of T cells into cells that produce unique cytokine profiles. Most importantly, we demonstrated that PP DCs have the unique capacity to induce the differntiation of T cells that produce high levels of IL-10, a cytokine important for the IgA B cell differentiation. These studies thus are some of the first to directly demonstrate that DCs from different tissues may be unique in their ability to induce tissue specific immunity. Over the past year we have initiated studies on the role of these DC subsets in models of inflammatory bowel disease and in murine infection with reovirus, a model intestinal virus infection. We found that DN DCs in the subepithelial dome region of the PP process viral antigen from virally infected apoptotic epithelial cells.

这个项目的重点是研究抗原在小鼠肠道中的加工过程。虽然很明显，口腔抗原暴露的结果可能是阳性的，即粘膜IgA反应的发展，在某些情况下也会诱导全身免疫，或者是阴性的，即诱导口服耐受，但为什么会发生这种或那种结果的细节是复杂的，而且知之甚少。虽然已知抗原制剂、佐剂的存在、抗原剂量以及遗传因素可以影响粘膜免疫反应，但这些因素如何影响免疫却从未确定过。在之前的研究中，我们已经在Peyer’s patch （PP）和固有层中建立了不同抗原呈递细胞群的存在，并使用原位免疫荧光显微镜和原位杂交，纯化细胞的流式细胞术，以及细胞因子产生（ELISA和定量RT-PCR）和T细胞分化的体外测定，详细描述了PP中dc的表面表型，功能和迁移。我们确定在PP中存在3个独立的未成熟dc亚群，淋巴（CD8+）、髓系（CD11b+）和双阴性（DN） dc，它们既不表达CD8也不表达CD11b。这些分离的DC亚群位于PP的不同位置，能够诱导T细胞分化为产生独特细胞因子谱的细胞。最重要的是，我们证明了PP dc具有诱导T细胞分化的独特能力，可以产生高水平的IL-10， IL-10是一种对IgA B细胞分化很重要的细胞因子。因此，这些研究是第一批直接证明来自不同组织的树突状细胞在诱导组织特异性免疫的能力方面可能是独特的。在过去的一年里，我们已经开始研究这些DC亚群在炎症性肠病模型和呼肠孤病毒（一种肠道病毒感染模型）感染小鼠中的作用。我们发现在PP的上皮下穹丘区域的DN dc处理来自病毒感染的凋亡上皮细胞的病毒抗原。