Spectrum of Autoimmune Gastrointestinal Dysmotility

描述(申请人提供)：本研究的目的是在动物模型上探讨自身免疫性胃肠道(G.I.)的免疫致病机制(S)。运动障碍。以肠神经系统(ENS)神经节和外源性自主神经节为靶点的自身免疫在临床上与肺癌相关，并可能是几种特发性胃肠动力障碍的原因之一，包括无法用公认的基因缺陷解释的先天性病例。这项研究计划的基本原理是基于在副肿瘤实体患者的神经节中发现的炎症病理，以及在血清中发现的免疫球蛋白标志物。公认的免疫球蛋白标志物是神经节细胞烟碱型乙酰胆碱受体(AChR)和神经细胞核和细胞质抗原的特异性标记。在一些特发性胃肠动力障碍患者中也发现了神经节AChR特异性抗体。在用神经节AChRA3亚单位的重组片段或合成肽免疫的兔中，这种抗体伴随着胃肠动力障碍，当注射到健康小鼠体内时，会导致胃肠动力障碍。其具体目的是：1)阐明AChR-Ig G在成年动物中致病的机制，2)研究AChR-Ig G通过胎盘转移胃肠动力障碍的可能性，3)确定与胃肠运动障碍有关的Ig G和T细胞反应的抗原决定簇，并确定炎症性神经节炎是否会因免疫策略而导致炎症性神经节炎，这些免疫策略旨在激活神经核、胞浆或AChR抗原多肽的特异性细胞毒素(CD8)T细胞。方法包括：胃肠动力功能测试，神经节突触传递的细胞内微电极研究，细胞和体液免疫反应的分析，单抗神经节细胞AChR-lgGs的产生和鉴定，使用眼镜蛇毒素来消耗补体，使用缺乏补体调节蛋白或Fc受体的敲除小鼠所需的免疫球蛋白依赖的细胞介导的细胞毒作用，神经节组织的组织学、免疫组织化学和电子显微镜分析，以及在子宫内暴露于AChR-Ig G的GFP转基因小鼠ENS发育阶段的时间推移荧光显微镜记录。来自这些研究的预期见解将改善特发性G.L.运动障碍的诊断和分类，并证明早期考虑免疫调节治疗的合理性。这项拟议的研究对癌症免疫也具有很高的临床相关性。

DESCRIPTION (provided by applicant): The objective of this research proposal is to investigate in animal models the immunopathogenic mechanism(s) accounting for autoimmune gastrointestinal (G.I.) dysmotility. Autoimmunity targeting neurons in ganglia of the enteric nervous system (ENS), and extrinsic autonomic ganglia, is well-documented clinically in association with lung cancer, and may be a cause of several idiopathic forms of G.I. dysmotility, including congenital cases that are not explained by recognized gene defects. The rationale for the research plan is based on the inflammatory pathology found in ganglia, and IgG markers found in serum, of patients with the paraneoplastic entity. Recognized IgG markers are specific for ganglionic nicotinic acetylcholine receptor (AChR) and neuronal nuclear and cytoplasmic antigens. IgG specific for the ganglionic AChR is also found in some patients with idiopathic G.I. dysmotility. This IgG accompanies G.I. dysmotility in rabbits immunized with recombinant fragments or synthetic peptides of the ganglionic AChR a3 subunit, and causes G.I. dysmotility when injected into healthy mice. The Specific Aims are: 1)to elucidate mechanisms responsible for the pathogenicity of AChR-IgG in adult animals, 2) investigate the potential of AChR-IgG to transfer G.I. dysmotility transplacentally, 3) define antigenic determinants of IgG and T cell responses contributing to G.I. dysmotility, and determine if inflammatory ENS ganglionitis will result from immunization strategies designed to activate cytotoxjc (CD8+) T cells specific for peptides derived from neuronal nuclear, cytoplasmic or AChR antigens. Methods include functional tests of G.I. motility, intracellular microelectrode studies of ganglionic synaptic transmission, analyses of cellular and humoral immune responses, production and characterization of monoclonal ganglionic AChR-lgGs, use of cobra venom factor to deplete complement, use of knock-out mice deficient in complement regulatory proteins or Fc receptors required for IgG-dependent cell-mediated cytotoxicity, histological, immunohistochemical and electronmicroscopic analyses of ganglionic tissues, and time lapse fluorescence photomicroscopic recording of ENS development stages in GFP transgenic mice exposed in utero to AChR-IgG. Insights anticipated from these studies will improve the diagnosis and aid classification of idiopathic G.l.dysmotilities, and justify early consideration of immunomodulatory therapies. The proposed research also has high clinical relevance to cancer immunity.