Regulation of T cell responses to oral antigens

口服抗原引发的免疫反应可能会产生重大的临床后果。树突状细胞 是口腔耐受的最重要的细胞决定因素之一，因为它们的任务是在粘膜中 还包含来自大量共生微生物区系的抗原和模式刺激的环境，具有 决定是否应该动员适应性免疫或对给定的抗原耐受。我们最近做了 建立自发性Th2相关性小肠疾病(SI)DC特异性小鼠模型 称为TRAF6ΔDC，最初似乎是微生物区系依赖的，因为抗生素治疗 改善性的。然而，与无菌(GF)ΔDC小鼠相比，无菌(GF)TRAF6 DC小鼠表现出令人惊讶的恶化疾病 小鼠被安置在特定的无病原体(SPF)条件下，这表明触发因素不是微生物区系。我们 现在有初步发现，在喂食无抗原(AF)的小鼠中，TRAF6ΔDC病完全得到改善 饮食，表明疾病的驱动力是食物抗原。TRAF6ΔDC模型可用于 揭示支持DC介导的口服耐受的新机制，因此我们提出如下建议 具体目的：1.探讨TRAF6、Δ、DC口服抗原敏感性的免疫学机制。我们 建议在口服的背景下进一步表征TRAF6ΔDC小鼠的免疫异常 抗原敏感性用于阐明连接口腔发育和维持的新的免疫学机制 树突状细胞对TRAF6介导信号的耐受性。在这方面，我们将研究相关的元胞因素，如 以及调节和效应分子，以确定在口服药物存在的情况下，体内平衡是如何被破坏的 抗原。我们将使用白喉毒素受体(DTR)转基因小鼠来检测 在DC特异性TRAF6缺乏和口服耐受的背景下对各种类型DC的消融 维护以开始确定TRAF6是否向某些细胞类型提供关键的支持耐受信号 而不是在它缺席的情况下创造功能失调的DC。模型口服抗原也将用于TRAF6ΔDC小鼠 更好地界定疾病发展的机制(S)。2.调查微生物区系的独立效应 抗生素对TRAF6、Δ、DC口服抗原敏感性的影响。TRAF6ΔDC病的抗生素治疗 微生物区系的缺失表明抗生素对免疫细胞具有潜在的生物相关性直接作用 我们建议在TRAF6ΔDC口服抗原敏感性的背景下进行研究 没有微生物区系和/或食物抗原。虽然我们通常会采用广谱的四人鸡尾酒 来自不同类别的抗生素药物用于微生物菌群枯竭，我们在这些研究中的假设 首先将重点放在氨苄西林的作用上，它属于β-内酰胺类，以前 据报道具有直接的生物免疫调节活性。此外，我们还将检查抗生素的效果 SPF和GF条件下TRAF6-ΔDC新生儿口服抗原敏感性的研究 抗生素治疗、共生微生物定植和口腔抗原敏感性之间的关系。

Immune responses triggered by oral antigens can have significant clinical consequences. Dendritic cells (DCs) are among the most important cellular determinants of oral tolerance, as they are tasked, in a mucosal environment that also contains antigens and pattern stimuli derived from vast commensal microbiota, with deciding whether adaptive immunity should be mobilized or tolerized to given antigens. We have recently generated a DC-specific mouse model of spontaneous Th2-associated disease of the small intestine (SI) called TRAF6ΔDC, which initially appeared to be microbiota-dependent because antibiotic treatment is ameliorative. However, germ-free (GF) TRAF6ΔDC mice surprisingly exhibit exacerbated disease compared to mice housed under specific pathogen-free (SPF) conditions, suggesting a trigger other than microbiota. We now have preliminary findings that TRAF6ΔDC disease is completely ameliorated in mice fed antigen-free (AF) diet, suggesting the driving stimulus of disease is food antigen. The TRAF6ΔDC model may be employed to reveal novel mechanisms underpinning DC-mediated oral tolerance, and thus we propose the following specific aims: 1. Investigate the immunological mechanisms of TRAF6ΔDC oral antigen sensitivity. We propose to further characterize the immunologic abnormalities of TRAF6ΔDC mice in the context of oral antigen sensitivity to elucidate novel immunologic mechanisms linking development and maintenance of oral tolerance to TRAF6-mediated signals in DCs. In this respect, we will examine the relevant cellular actors, as well as regulatory and effector molecules to determine how homeostasis is disrupted in the presence of oral antigen. We will use diphtheria toxin receptor (DTR) transgenic mice to examine the effects of temporal ablation of various types of DCs in the context of both DC-specific TRAF6 deficiency and oral tolerance maintenance to begin to determine whether TRAF6 provides key pro-tolerance signals to certain cell types versus creating dysfunctional DCs in its absence. Model oral antigen will also be utilized in TRAF6ΔDC mice to better define the mechanism(s) of disease development. 2. Investigate the independent effects of microbiota and antibiotics on TRAF6ΔDC oral antigen sensitivity. Mitigation of TRAF6ΔDC disease by antibiotics in the absence of microbiota suggests potential biologically relevant direct effects of antibiotics on immune cells which we propose to investigate in the context of TRAF6ΔDC oral antigen sensitivity in the presence or absence of microbiota and/or food antigens. While we typically employ a broad-spectrum cocktail of four antibiotic drugs from different classes for the purpose of microflora depletion, our hypothesis in these studies will initially focus on the role of ampicillin, which belongs to the β-lactam class that has been previously reported to have direct biotic immunomodulatory activity. Additionally, we will examine the effects of antibiotics on oral antigen sensitivity in TRAF6ΔDC neonates under SPF and GF conditions to determine temporal relationships between antibiotic treatment, commensal microbiotic colonization, and oral antigen sensitivity.