Immune Suppression of Collagen Arthritis

描述（由申请人提供）：风湿性关节炎是一种慢性关节炎性疾病。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，即抗原驱动的自身免疫过程介导关节损伤，是基于我们的发现，即在我们的开放标签试验中，关节炎患者口服CII导致测量的细胞因子谱发生有利的改变。这些数据支持这样的观点，即对软骨中抗原如CII的自身免疫在疾病的发病机制中起主要作用。我们已经使用携带DRB 1 * 0101和DRB 1 * 0401转基因的人源化小鼠和胶原诱导的关节炎（CIA）模型来开发基于胶原的免疫疗法。通过使用增殖和细胞因子测定，我们发现Tg小鼠中由DR 1和DR 4两者呈递给小鼠T细胞的免疫显性决定簇的核心是CII 263 - 270（FKGEQGPK）。随后，开发了一种合成类似物肽CII 263 - 273（F263N，E266D）（A12），发现其在建立自身免疫性关节炎后给药时诱导CIA的深度抑制。基于这些数据，我们提出以下假设：A12类似物肽/APC复合物与TCR的相互作用导致独特的信号传导途径，很可能涉及Syk而不是ZAP 70的磷酸化。所产生的信号传导事件级联主要诱导Th2细胞因子并最终抑制关节炎。我们提出以下目标：1）鉴定由A12激活的T细胞信号传导途径，并将它们与由野生型CII-肽诱导的途径进行比较。2)表征由A12诱导的抑制性T细胞，并确定该选择的群体如何抑制对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类似物抑制对CII和关节炎的免疫力方面的作用。这些研究将确定A12触发了哪些细胞内信号传导途径，这些途径与未改变的肽配体和完整的CII触发的途径有何不同，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RA患者如何成功地用A12治疗提供必要的初步数据。公共卫生相关性：该R01是一种新的应用，其中我们使用携带DRB 1 * 0101和DRB 1 * 0401转基因的人源化小鼠和胶原诱导的关节炎（CIA）模型来开发基于胶原的免疫疗法。

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.