Immune Suppression of Collagen Arthritis

描述(申请人提供)：类风湿性关节炎是一种慢性腹泻关节炎症性疾病。在初步研究中，我们发现50%的RA患者对II型胶原(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了关节损伤，这是基于我们的研究结果，即在我们的开放标签试验中，对关节炎患者口服CII导致了所测量的细胞因子谱的有利变化。这些数据支持对软骨中的抗原(S)的自身免疫在疾病的发病机制中起主要作用的观点。我们使用携带DRB1*0101和DRB1*0401转基因的人源化小鼠和胶原诱导性关节炎(CIA)模型来开发基于胶原的免疫疗法。通过增殖和细胞因子分析，我们发现DR1和DR4在TG小鼠体内呈递给小鼠T细胞的免疫优势决定簇的核心是CII263-270(FKGEQGPK)。随后，合成的模拟多肽CII 263-273(F263N，E266D)(A12)被发现在自身免疫性关节炎建立后给药时对CIA有显著的抑制作用。基于这些数据，我们提出了以下假设：A12模拟肽/APC复合体与TCR的相互作用导致了一条独特的信号通路，很可能涉及Syk而不是ZAP 70的磷酸化。由此产生的一系列信号事件主要诱导Th2细胞因子，最终抑制关节炎。我们提出了以下目标：1)鉴定A12激活的T细胞信号通路，并将其与野生型CII多肽诱导的信号通路进行比较。2)确定A12诱导的抑制性T细胞的特性，并确定该人群如何抑制对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类似物在抑制对CII和关节炎的免疫方面的作用。这些研究将确定A12触发了哪些细胞内信号通路，这些信号通路与未改变的多肽配体和完整的CII触发的信号通路有何不同，以及这种变化对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类风湿关节炎患者如何成功地使用A12治疗提供必要的初步数据。

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.