Immune Suppression of Collagen Arthritis

描述（由申请人提供）：类风湿关节炎是一种慢性炎症性疾病的腹泻关节。在初步研究中，我们发现50%的RA患者对II型胶原蛋白（CII）产生显著的T细胞反应。我们的假设是抗原驱动的自身免疫过程介导关节损伤，这是基于我们的发现，在我们的开放标签试验中，关节炎患者口服CII导致细胞因子谱的有利改变。这些数据支持了对软骨中CII等抗原的自身免疫在该疾病的发病机制中起主要作用的观点。本研究以携带DRB1*0101和DRB1*0401转基因的人源化小鼠和胶原诱导关节炎（CIA）模型为研究对象，建立了基于胶原蛋白的免疫疗法。通过增殖和细胞因子实验，我们发现DR1和DR4在Tg小鼠中呈现给小鼠t细胞的免疫显性决定因子的核心是CII263-270 （FKGEQGPK）。随后，一种合成的类似肽CII 263-273 (F263N, E266D) （A12）被开发出来，发现在自身免疫性关节炎建立后给药可诱导CIA的深度抑制。基于这些数据，我们提出以下假设：A12类似肽/APC复合物与TCR的相互作用导致了一个独特的信号通路，很可能涉及Syk而不是ZAP 70的磷酸化。由此产生的信号事件级联主要诱导Th2细胞因子并最终抑制关节炎。我们提出以下目标：1)鉴定A12激活的t细胞信号通路，并将其与野生型cii肽诱导的信号通路进行比较。2)表征A12诱导的抑制性T细胞，并确定这一选定的群体如何抑制对CII和自身免疫性关节炎的免疫。3)确定翻译后修饰在增强A12类似物抑制CII和关节炎免疫作用中的作用。这些研究将确定由A12触发的细胞内信号通路，这些信号通路与未改变的肽配体和完整的CII触发的信号通路有何不同，以及这种改变对T细胞表型的影响。从这些小鼠研究中获得的信息将为了解如何成功地用A12治疗RA患者提供必要的初步数据。公共卫生相关性：该R01是我们利用携带DRB1*0101和DRB1*0401转基因的人源化小鼠和胶原诱导关节炎（CIA）模型开发基于胶原的免疫疗法的新应用。

DESCRIPTION (provided by applicant): Rheumatoid arthritis is a chronic inflammatory disease of diarthrodial joints. In preliminary studies we find that 50% of RA patients produce significant T cell responses to type II collagen (CII). Our hypothesis, that an antigen-driven autoimmune process mediates articular injury, is based on our findings that the oral administration of CII to arthritis patients in our open label trials resulted in favorable alterations in the cytokine profile measured. These data support the view that autoimmunity to an antigen(s) such as CII in cartilage plays a major role in the pathogenesis of the disease. We have used humanized mice bearing DRB1*0101 and DRB1*0401 transgenes and the collagen- induced arthritis (CIA) model to develop a collagen-based immunotherapy. By using proliferation and cytokine assays, we found that the core of the immunodominant determinant presented to murine T-cells by both DR1 and DR4 in Tg mice is CII263-270 (FKGEQGPK). Subsequently, a synthetic analog peptide was developed CII 263-273 (F263N, E266D) (A12) that was found to induce a profound suppression of CIA when administered after autoimmune arthritis has been established. Based on these data, we propose the following hypothesis: Interaction of the A12 analog peptide/APC complex with TCR leads to a unique signaling pathway, very likely involving phosphorylation of Syk rather than ZAP 70. The resulting cascade of signaling events induces predominantly Th2 cytokines and ultimately suppression of arthritis. We propose the following aims: 1) Identify T-cell signaling pathways activated by A12 and compare them with pathways induced by the wild type CII-peptide. 2) Characterize the inhibitory T cells induced by A12 and ascertain how this selected population can inhibit immunity to CII and autoimmune arthritis. 3) Determine the role of post-translational modifications in enhancing the efficacy of the A12 analog in suppressing immunity to CII and arthritis. These studies will determine what intracellular signaling pathways are triggered by A12, how these differ from those triggered by the unaltered peptide ligand and intact CII, and the consequences of this alteration on T cell phenotype. Information gained from these murine studies will provide preliminary data necessary for understanding how RA patients can successfully be treated with A12. PUBLIC HEALTH RELEVANCE: This R01 is a new application in which we use humanized mice bearing DRB1*0101 and DRB1*0401 transgenes and the collagen-induced arthritis (CIA) model to develop a collagen-based immunotherapy.