dnTGF Beta RII Mice and PBC

描述（由申请人提供）：原发性胆汁性肝硬化（PBC）是一种肝脏特异性自身免疫性疾病，其特征为门脉淋巴细胞浸润、选择性破坏胆管上皮细胞和存在抗线粒体抗体（AMA）。PBC的发病隐匿性和对人类肝脏的限制阻碍了PBC研究的进展。我们利用了一种转基因小鼠，在CD 4启动子的指导下，定向表达转化生长因子（TGF）-2受体II型（dnTGF 2 RII）的显性阴性形式，并证明了这些小鼠产生PBC的几个关键特征，包括自发产生针对PDC-E2、BCOADC-E2和OGDC-E2的AMA，这些AMA与患者识别的线粒体自身抗原相同。此外，与人类PBC患者相似，鼠线粒体自身抗体识别的表位是内部硫辛酰结构域，这些自身抗体也抑制酶功能。此外，dnTGF 2 RII小鼠具有由CD 4和CD 8细胞组成的强烈门静脉周围炎症以及与人PBC类似的血清细胞因子谱。本文研究的鼠构建体不同于病理学主要是溃疡性结肠炎的一般TGF-2-/-小鼠。相比之下，dnTGF 2 RII小鼠存活超过6个月，仅具有最小的溃疡性结肠炎，并且它们的主要病理表现在肝脏中。重要的是，我们的数据点远离启动自身免疫的机制，如分子模拟对激活的内在自我反应性T细胞库，其中缺乏必要的调节性T细胞的影响。我们建议进行详细的个体发育分析的免疫系统，以确定动力学的特定谱系有助于疾病的过程中，利用dnTGF 2 RII小鼠。我们将通过分析先天性、体液和细胞免疫系统、肝淋巴细胞亚群、肝组织病理学和自身抗体产生动力学来研究小鼠模型的免疫学方面。我们还将过继性转移来自dnTGF 2 RII小鼠的分离的CD 4+和/或CD 8 + T细胞，以解决涉及门脉炎症的T细胞效应机制。此外，我们将确定在没有B细胞的情况下的自然史和免疫病理学。我们的目标是扩展我们的试点数据，以严格确定该模型对人类PBC的有效性，并使未来的研究重点放在PBC的机制和潜在的治疗上。

DESCRIPTION (provided by applicant): Primary biliary cirrhosis (PBC) is a liver specific autoimmune disease, characterized by portal tract lymphocytic infiltration, selective destruction of biliary epithelial cells and the presence of anti-mitochondrial antibodies (AMAs). Advances in the study of PBC have been hampered by its cryptic onset, and limitations in accessing human liver. We have taken advantage of a mouse transgenic for directed expression of a dominant negative form of transforming growth factor (TGF)-2 receptor type II (dnTGF2RII), under the direction of the CD4 promoter, and demonstrated that these mice develop several key features of PBC including spontaneous production of AMAs directed to PDC-E2, BCOADC-E2 and OGDC-E2, the same mitochondrial autoantigens recognized by patients. In addition, the epitope recognized by murine mitochondrial autoantibodies, similar to human patients with PBC, is the inner lipoyl domain and these autoantibodies also inhibit enzyme function. Moreover, dnTGF2RII mice have intense periportal inflammation composed of CD4 and CD8 cells as well as a serum cytokine profile analogous to that of human PBC. The murine construct studied herein is distinct from generic TGF-2-/- mice whose pathology is primarily ulcerative colitis. In contrast, dnTGF2RII mice survive over 6 months with only minimal ulcerative colitis and their dominant pathology is manifest in liver. Importantly, our data point away from initiation of autoimmunity by mechanisms such as molecular mimicry towards activation of an intrinsically self-reactive T cell repertoire in which necessary regulatory T cell influences are lacking. We propose to perform a detailed ontogenetic analysis of the immune system to define the kinetics by which specific lineages contribute to the disease process by utilizing dnTGF2RII mice. We will study the immunological aspects of the mouse model by analyzing the innate, humoral and cellular immune systems, liver lymphoid subpopulations, liver histopathology and kinetics of autoantibody production. We will also adoptively transfer isolated CD4+ and/or CD8+ T cells from dnTGF2RII mice to address T cell effector mechanisms involved in portal tract inflammation. In addition, we will determine the natural history and immunopathology in the absence of B cells. Our goal is to extend our pilot data to rigorously determine the validity of this model for human PBC and to enable focused future studies directed at mechanisms and potential therapy for PBC.