Murine gene knock-in models fo Omenn Syndrome and leaky SCID

Omenn综合征(OS)是一种以严重的组织损伤为特征的综合免疫缺陷 浸润型、激活型、寡克隆型和无能T淋巴细胞。大多数OS患者缺乏循环B 淋巴细胞和严重的低丙种球蛋白血症，但血清IgE正常或升高。我们有 发现大多数OS患者携带RAG基因的亚型突变，这种突变减少但不会 废除V(D)J复合。然而，参与V(D)J重组的基因亚型突变 也可能导致渗漏的SCID，积聚激活的和无能的T细胞，而不会对组织造成损害。 我们发现转录因子Aire和组织特异性转录本在 OS患者的胸腺，增加了自身反应性T细胞的阴性选择的可能性 适当地就位。此外，调节性T细胞(Treg)的发育可能在OS中发生改变，因为 这些患者的胸腺缺少与Tregs发育有关的Hassall小体。最后， 环境因素也可能参与OS的病理生理学，因为已经证明 暴露于低形态RAG突变的婴儿的疾病表型可被显著改变 病原体。我们将利用最近开发的三个亚型RAG2，RAG1， 和Lig4突变，以研究OS和泄漏SCID背后的细胞和分子机制。 我们的总体假设是可变的临床和免疫学表型与 V(D)J重组相关基因的亚型突变反映了不同程度的脑损伤 V(D)J重组影响中枢耐受的缺失和非缺失机制 由此产生的表型可能会受到环境因素的影响。 为了验证这一假设，我们将评估突变体的V(D)J重组活性。我们将分析 在这些模型中使用负性选择，并使用采用迁移来评估功能受损的作用 特雷格斯。最后，我们将用TLR激动剂、MCMV和恶唑酮挑战小鼠，以沉淀或 加快疾病表型。 我们希望这些独特的动物模型的详细特征将提供关键信息 了解OS和渗漏SCID的病理生理学，以及其他更常见的 免疫调节。将收集的信息也可能对小说和 对于这些严重的免疫缺陷和反应障碍的情况，采取更适当的治疗形式。

Omenn syndrome (OS) is a combined immunodeficiency characterized by severe tissue damage due to infiltrating, activated, oligoclonal and anergic T lymphocytes. Most patients with OS lack circulating B lymphocytes and show profound hypogammaglobulinemia, but normal or elevated serum IgE. We have found that most patients with OS carry hypomorphic mutations of the RAG genes that decrease but do not abolish V(D)J recombination. However, hypomorphic mutations in genes involved in V(D)J recombination may also cause leaky SCID, with accumulation of activated and anergic T cells, without tissue damage. We have found that the transcription factor Aire and tissue-specific transcripts are poorly expressed in the thymus of patients with OS, raising the possibility that negative selection of autoreactive T cells may not be properly in place. In addition, development of regulatory T cells (Tregs) is likely to be altered in OS, as the thymus of these patients lacks Hassall's corpuscles, which are involved in Tregs development. Finally, environmental factors may also be involved in the pathophysiology of OS, as it has been shown that the disease phenotype in infants with hypomorphic RAG mutations can be dramatically modified by exposure to pathogens. We will take advantage of three recently developed murine models of hypomorphic rag2, ragl, and Iig4 mutations to investigate the cellular and molecular mechanisms that underlie OS and leaky SCID. Our overall hypothesis is that the variable clinical and immunological phenotype associated with hypomorphic mutations in genes involved in V(D)J recombination reflects a different degree of impairment of V(D)J recombination that affects deletional and non deletional mechanisms of central tolerance, and that the resulting phenotype may be modified by environmental factors. To test this hypothesis,we will evaluate the V(D)J recombination activity of the mutants. We will analyze negative selection in these models, and use adoptive transfer to assess the role of impaired function of Tregs. Finally, we will challenge the mice with TLR agonists, MCMV and oxazolone to precipitate or accelerate the disease phenotype. We expect that detailed characterization of these unique animal models will provide critical information to understand the pathophysiology of OS and leaky SCID, but also of other, more common, disorders of immune regulation. The information that will be collected might be useful also for development of novel and more appropriate forms of treatment of these severe conditions of immune deficiency and dysreactivity.