Antigen Processing And Presentation In The Intestine

抗原在肠道中的加工和呈现

• 批准号: 7964413
• 负责人: BRIAN KELSALL
• 金额: $ 126.31万
• 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/7964413
• 关键词: Adjuvant; Affect; Antigen Presentation Pathway; Antigen-Presenting Cells; Antigens; Apoptotic; Autoimmune Diseases; B cell differentiation; Bacterial DNA; Blood; Bone Marrow; CD8B1 gene; Cell Differentiation process; Cells; Colon; Complex; Dendritic Cells; Development; Disease; Dose; Drug Formulations; Enzyme-Linked Immunosorbent Assay; Epithelial Cells; Feedback; Flow Cytometry; Genetic; Goals; Granulocyte-Macrophage Colony-Stimulating Factor; Growth Factor; ITGAM gene; Immune response; Immunity; Immunoglobulin A; Immunohistochemistry; Immunosuppression; In Situ; In Situ Hybridization; Infection; Inflammation; Inflammatory Bowel Diseases; Inflammatory disease of the intestine; Interferons; Interleukin-10; Interleukin-12; Intestines; Lamina Propria; Lymphoid; Mediating; Methods; Microscopy; Modeling; Molecular; Mucosal Immune Responses; Mus; Myelogenous; Oligonucleotides; Oral; Organ Transplantation; Outcome; Patients; Phenotype; Phosphorylation; Physiological; Population; Process; Production; Regulation; Reovirus Type 1; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Transduction; Site; Spleen; Structure of aggregated lymphoid follicle of small intestine; Surface; T-Lymphocyte; TLR9 gene; Tissues; Transforming Growth Factor beta; Transplant Recipients; Treatment Efficacy; Viral Antigens; Virus Diseases; acquired immunity; antigen processing; autocrine; chemokine; commensal microbes; cytokine; improved; in vitro Assay; influenzavirus; migration; monocyte; mouse model; neutrophil; novel; oral tolerance; oral vaccine; pathogen; peripheral blood; progenitor; receptor; response

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 were some of the first to directly demonstrate that DCs from different tissues may be unique in their ability to induce tissue specific immunity. We have also recently demonstrated that DN DCs in the subepithelial dome region of the PP process viral antigen from virally infected apoptotic epithelial cells. Furthermore, we previously determined that clearance of lethal experimental infection with a model mucosal virus infection, type 1 reovirus, is dependent on type-1 interferon production in the PP,that PP DCs and not epithelial cells at this site are major producers of type-1 interferon during infection. This indicates that type-1 interferon production by bone-marrow derived cells, and most clearly by dendritic cells within the PP is a primary determinant of whether this mucosal pathogen survives and is disseminated to other tissues. Furthermore, we localized and studied the function of plasmacytoid DCs (pDCs) from the Peyer's patch. PP pDCs were localized to the interfollicular and subepithelial dome region of the PP by immunohistochemistry, exressed typical surface markers for pDCs from other tissues, as examined by flow cytometry, and produced IL-12 but little type-1 interferon following stimulation with either influenza virus, or bacterial DNA. The lack of type-1 interferon production by PP pDCs is signfifcant because this is different from pDCs from other tissues. Furthermore, we determined that factors present in the microenvironment of the PP, in particular PGE(2), TGFbeta, and IL-10 were able to suppress type-1 interferon production by pDCs from the spleen, suggesting that microenvironmental factors may influence type-1 interferon production by pDCs. The lack of type-1 interferon producton by PP pDCs may help control untoward immune responses to commensal bacteria, and thus be pivotal in regulating intestinal inflammation, as occurs in inflammtory bowel diseases. Furthermore, we have studied the mechanisms by which TGFbeta and IL-10 regulate type-1 IFN prodution by pDCs in response to CpG oligonucleotides. We determined that TGFbeta appears to act on the initial CpG signal mediated by toll-like receptor 9 (TLR9), which IL-10 appears to act on both intital TLR9 signals as well as dominantly on the autocrine feedback that type-1 IFN proovides though the IFNalpha/beta receptor. The suppression by IL-10 is mediated through suppression STAT-1-phosphorylation in response to type-1 IFN. We have also begun to understand the subpopulations DCs in the colon of mice and their progenitors. In particular we find that there is one particular population so of cells that is replenished by peripheral blood monocytes, while the others appear to be derived from other blood precursors. Furthermore, we have begun to study the requirement for certain chemokine recpetors on T cells that are important for trafficing into the colon during inflammation in mouse models of inflammatory bowel disease. Finally, we have studied the ability of granulocyte-macrophage colony stimulating factor (GM-CSF), a growth factor that is commonly used to treat organ transplant patients to improve their production of neutrophil and monocyte after immunosuppression, to treat patients with inflammatory bowel disease. Treatment efficacy was correlated with changes in peripheral blood T cell production of IL-10, and sustained changes in the numbers of plasmacytoid DCs. As plasmacytoid DCs have been shown to drive non-pathogenic Th2 responses, these studies suggest that treatmetns that enhance the number of plasmacytoid DCs in the blood, may have therapeutic efficacy in Th1-mediated autoimmune disorders.

该项目的重点是抗原如何在小鼠肠道中加工。虽然很明显口服抗原暴露的结果可能是阳性的，即，粘膜伊加应答的发展，以及在某些情况下全身免疫的诱导，或阴性，即，口服耐受性的诱导，以及为什么会发生一种或另一种结果的细节是复杂的，并且知之甚少。虽然已知抗原制剂、佐剂的存在和抗原剂量以及遗传因素可影响粘膜免疫应答，但这些因素如何影响免疫力从未确定。在以前的研究中，我们已经建立了不同的抗原呈递细胞群的存在下，在派尔集合淋巴结（PP）和固有层，并详细的表面表型，功能和迁移的DC在PP中使用原位免疫荧光显微镜和原位杂交，流式细胞术纯化的细胞，并在体外测定细胞因子的产生（ELISA和定量RT-PCR）和T细胞分化。我们确定PP中存在3个独立的未成熟DC亚群，即淋巴样（CD 8+）、骨髓样（CD 11b+）和双阴性（DN）DC，它们既不表达CD 8也不表达CD 11b。这些分离的DC亚群位于PP中的不同位点，并且能够诱导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PP DC具有诱导产生高水平IL-10的T细胞分化的独特能力，IL-10是对伊加B细胞分化重要的细胞因子。因此，这些研究是第一批直接证明来自不同组织的DC在诱导组织特异性免疫的能力方面可能是独特的。 我们最近也证明，在PP的上皮下圆顶区域的DN DC处理来自病毒感染的凋亡上皮细胞的病毒抗原。此外，我们以前确定，清除致命的实验感染与模型粘膜病毒感染，1型呼肠孤病毒，是依赖于1型干扰素生产的PP，PP DC，而不是在这个网站的上皮细胞是主要生产商的1型干扰素在感染过程中。这表明，1型干扰素生产的骨髓来源的细胞，最明显的是树突状细胞内的PP是一个主要的决定因素，这种粘膜病原体是否存活，并传播到其他组织。此外，我们定位和研究浆细胞样树突状细胞（pDC）从派尔集合淋巴结的功能。PP pDCs通过免疫组织化学定位于PP的滤泡间和上皮下圆顶区域，通过流式细胞术检测，表达来自其他组织的pDCs的典型表面标志物，并且在用流感病毒或细菌DNA刺激后产生IL-12但几乎不产生1型干扰素。 PP pDC缺乏1型干扰素的产生是重要的，因为这与来自其他组织的pDC不同。此外，我们确定PP微环境中存在的因子，特别是PGE（2）、TGF β和IL-10能够抑制来自脾的pDC产生1型干扰素，这表明微环境因素可能影响pDC产生1型干扰素。PP pDC缺乏1型干扰素产生可能有助于控制对肠道细菌的不良免疫应答，因此在调节肠道炎症中是关键的，如在炎性肠病中发生的。 此外，我们还研究了TGF β和IL-10调节pDCs对CpG寡核苷酸应答的1型IFN产生的机制。 我们确定TGF β似乎作用于由Toll样受体9（TLR 9）介导的初始CpG信号，IL-10似乎作用于初始TLR 9信号以及主要作用于1型IFN通过IFN α/β受体提供的自分泌反馈。IL-10的抑制作用是通过抑制STAT-1-磷酸化应答1型IFN介导的。 我们也开始了解小鼠结肠中的DC亚群及其祖细胞。 特别是，我们发现有一个特定的细胞群，由外周血单核细胞补充，而其他细胞似乎来自其他血液前体。此外，我们已经开始研究T细胞上某些趋化因子受体的需求，这些趋化因子受体对于炎症性肠病小鼠模型中炎症期间进入结肠至关重要。 最后，我们研究了粒细胞-巨噬细胞集落刺激因子（GM-CSF）治疗炎症性肠病患者的能力，GM-CSF是一种生长因子，通常用于治疗器官移植患者，以改善其在免疫抑制后产生中性粒细胞和单核细胞。治疗效果与外周血T细胞产生IL-10的变化以及浆细胞样DC数量的持续变化相关。由于浆细胞样DC已显示驱动非致病性Th 2应答，因此这些研究表明，增加血液中浆细胞样DC数量的治疗可能对Th 1介导的自身免疫性疾病具有治疗功效。