Spectrum of Autoimmune Gastrointestinal Dysmotility

描述（由申请人提供）：本研究计划的目的是在动物模型中研究自身免疫性胃肠道（G.I.）运动障碍的免疫致病机制。针对肠神经系统（ENS）神经节和外源性自主神经节神经元的自身免疫在临床上与肺癌相关，并且可能是几种特发性胃肠道运动障碍的原因，包括无法用公认的基因缺陷解释的先天性病例。研究计划的基本原理是基于在神经节中发现的炎症病理，以及在副肿瘤实体患者的血清中发现的IgG标记物。公认的IgG标记物对神经节烟碱乙酰胆碱受体（AChR）和神经元核和细胞质抗原具有特异性。在一些特发性G.I.运动障碍患者中也发现特异于神经节AChR的IgG。该IgG在用神经节AChR a3亚基重组片段或合成肽免疫的家兔中伴随G.I.运动障碍，并在注射到健康小鼠时引起G.I.运动障碍。具体目标是：1)阐明成年动物中AChR-IgG致病性的机制；2)研究AChR-IgG经胎盘转移G.I.运动障碍的潜力；3)确定导致G.I.运动障碍的IgG和T细胞反应的抗原决定因素，并确定炎症性ENS神经节炎是否会由免疫策略引起，该免疫策略旨在激活细胞毒（CD8+） T细胞，特异性地针对源自神经元核、细胞质或AChR抗原的肽。方法包括G.I.运动功能测试，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分析，单克隆神经节achr - lgg的产生和表征，使用眼镜蛇毒液因子消耗补体，使用敲除缺乏补体调节蛋白或igg依赖性细胞介导的细胞毒性所需的Fc受体的小鼠，组织学，在子宫内暴露于AChR-IgG的GFP转基因小鼠神经节组织的免疫组织化学和电镜分析，以及ENS发育阶段的延时荧光显微镜记录。从这些研究中预期的见解将改善特发性g.l.g运动障碍的诊断和辅助分类，并证明早期考虑免疫调节疗法是合理的。这项研究对癌症免疫也有很高的临床意义。

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.