Control of high-affinity IgE responses to animal venoms by skin innate type 2 immunity

了解组织的先天2型反应是如何诱导的，以及这些局部组织反应如何指导全身适应性2型反应是生物医学研究中的一个关键问题。皮肤组织在接触毒液时，例如通过爬行动物或昆虫叮咬，会产生重要的2型反应。这些2型反应可以提供天然的和适应性的，IgE介导的保护，甚至抵抗毒液毒性，但另一方面，经常导致威胁生命的过敏性致敏。毒液触发局部2型免疫的分子机制和细胞相互作用尚不清楚，暴露于毒液的皮肤发出的信号也不清楚，这些信号指示皮肤引流淋巴(LN)中的适应性2型免疫。这些2型反应虽然原则上是保护性的，但经常出错导致过敏反应，这是一个相关的重要问题。我们假设，组织对毒液的即时反应以及随后的真皮和LN 2型细胞的激活指示抗蛇毒IgE的产生和亲和力，从而决定有益的或潜在的致命结果。尽管在理解生发中心反应方面取得了相当大的进展，通过通过超突变的IgG1进行顺序类别转换来产生高亲和力的IgE，但对组织2型反应所施加的这一过程的控制仍然难以捉摸。为了了解从蛇毒注射部位开始的天然组织反应对高亲和力抗蛇毒IgE反应的指导作用，我们将研究毒素如何影响注射部位LN引流部位的皮肤常驻DC以及迁徙和LN驻留的DC群体。我们将探讨保护性高亲和力抗蛇毒IgE反应对单个细胞类型和固有信号通路的要求。我们将解决关键问题，即低亲和力和高亲和力的IgE反应如何与耐药性或过敏反应相关。我们将广泛依赖与其他组织的相互作用，解决以下具体任务：(1)量化蛇毒或蛇毒成分诱导的IgE与蛋白酶过敏原和蠕虫抗原的亲和力和亲和力成熟的动力学；(2)确定注射蛇毒的皮肤DC中诱导高亲和力IgE的激活信号。具体识别依赖或不依赖IL-33/ST2和/或肥大细胞的信号；(3)确定注射蛇毒激活的皮肤引流LN的DC、肥大细胞和巨噬细胞的信号；(4)阐明高亲和力IgE反应所需的固有途径和细胞类型；(5)确定对过敏反应的抵抗力如何取决于高亲和力或低亲和力IgE的产生。总之，我们的工作将阐明皮肤对毒液的2型反应模式的性质，以及这种反应与生发中心的联系，并将揭示“抵抗力与过敏反应决定”的关键特征。

Understanding how innate type 2 responses of tissues are induced and how these local tissue responses instruct systemic adaptive type 2 responses is a key question in biomedical research. Skin tissue mounts important type 2 responses upon exposure to venoms e.g. through bites of reptiles or insect stings. These type 2 responses can provide innate and adaptive, IgE-mediated protection, even resistance, against venom toxicity, but on the other hand, frequently lead to life-threatening allergic sensitization. Molecular mechanisms and cellular interplay triggered by venoms to induce local type 2 immunity are unclear, as are the signals from venom-exposed skin that instruct adaptive type 2 immunity in the skin-draining lymph node (LN). How these type 2 responses, while in principle protective, frequently go awry to cause anaphylaxis, is a related important question.We hypothesize that the immediate tissue response to the venom and subsequent activation of dermal and LN type 2 cells instructs amounts and affinity of the anti-venom IgE produced and thereby determines the beneficial or potentially fatal outcome. Despite considerable progress in understanding germinal center responses that produce high-affinity IgE through sequential class switching via hypermutated IgG1, the control of this process exerted by the tissue 2 type response remains elusive. To understand instruction of high-affinity anti-venom IgE responses by the innate tissue response starting at the site of venom injection, we will investigate how venom affects skin-resident DCs as well as migratory and LN-resident DC populations in the LN draining the injection site. We will probe the requirement for individual cell types and innate signaling pathways for protective high-affinity anti-venom IgE responses. We will address the key question of how low- and high-affinity IgE responses correlate with resistance or anaphylaxis. Extensively relying on interactions with other FOR groups, we will address the following specific tasks: (1) Quantify affinity and kinetics of affinity maturation of IgE elicited by venoms or venom components in comparison to protease allergens and helminth antigens; (2) determine signals activated in DCs in skin injected with venoms that induce high-affinity IgE. Specifically identify signals which depend on, or are independent of IL-33/ST2 and/or mast cells; (3) determine signals activated by venom injection in DCs, mast cells and macrophages of skin-draining LNs; (4) elucidate innate pathways and cell types required for high-affinity IgE responses; (5) determine how development of resistance versus anaphylaxis depends on high- or low-affinity IgE production. Collectively, our work will elucidate the nature of the skin type 2 response pattern to venoms and the communication of this response to the germinal center and will reveal key features of the “resistance versus anaphylaxis decision”.