ANALOG PEPTIDES EFFECTS ON COLLAGEN INDUCED ARTHRITIS

胶原诱导性关节炎是一种实验性自身免疫性关节炎 通过免疫遗传易感小鼠品系诱导， II型胶原（CII）。它与人类有几个重要特征 类风湿关节炎其特征在于对CII的免疫应答， 包括T细胞的活化和致关节炎的 自身抗体，最终在诱导滑膜炎，和 释放破坏组织的降解酶。以前的工作 我们的实验室已经确定了II型胶原蛋白的区域，CII 260-270， 作为免疫显性T细胞表位在对I- A（q）荷瘤小鼠。T细胞的活化首先需要形成 抗原肽与主要组织相容性复合物之间的复合物 (MHC)分子。然后这些复合物被T细胞识别 受体（TcR）的抗原特异性T细胞。这三个人的形成-- 分子复合物是T细胞活化过程中必不可少的起始事件 细胞和随后的致关节炎抗体的产生， 关节炎的发展。因此，开发一种破坏 在三分子复合物的背景下T细胞的活化可以 从而导致抑制关节炎重要治疗策略。在 为了产生具有破坏I-A（q）-的潜力的类似肽， 限制性抗原提呈，合成类似物肽被开发 其在CII内的选定残基处含有氨基酸取代， 260-270.这些类似肽之一，A9（CII 245-270 [s260，261，263]）， 发现能够在体外抑制T细胞对CII的应答。 当DBA/1小鼠（H-2（q））被给予这种类似肽时， 关节炎的发病率和严重程度沿着 对CII的体液免疫反应。因此，我们计划确定 与I-A（q）相互作用的CII 260-270的氨基酸残基和 与TcR相互作用，以确定每个氨基酸的作用 残基在T细胞功能中起作用，并设计类似肽， 最有效地破坏T细胞功能。的潜在机制 这些抑制性肽的有效性将通过i） 分析淋巴因子分泌谱（TH 1与TH 2）， 当CII 260-270反应性T细胞暴露于野生型时， 型肽、A9类似物或其它抑制肽，和ii） 表征A9或其他抑制类似物 肽通过T细胞受体影响信号传导。特别关注 将重点关注TcR/CD 3相关蛋白的酪氨酸磷酸化 和磷脂酰肌醇的周转。从这些研究中获得的见解 将为设计类似肽的方法提供重要的经验教训 其可用于治疗人类自身免疫性关节炎。

Collagen-induced arthritis (CIA) is an experimental autoimmune arthritis induced by immunization of genetically susceptible strains of mice with type II collagen (CII). It shares several important features with human rheumatoid arthritis. It is characterized by an immune response to CII, including the activation of T cells, and production of arthritogenic autoantibodies that culminate in the induction of synovitis, and the release of degradative enzymes that destroy the tissues. Previous work in our laboratory has identified a region of type II collagen, CII 260-270, as the immunodominant T cell epitope in the immune response to CII of I- A(q)-bearing mice. Activation of T cells requires first a formation of complexes between antigenic peptides and major histocompatibility complex (MHC) molecules. These complexes then are recognized by the T cell receptors (TcR) of antigen-specific T cells. The formation of this tri- molecular complex is an essential initial event in the activation of T cells and subsequent production of arthritogenic antibodies and the development of arthritis. Therefore, developing a means of disrupting the activation of T cells within the context of the trimolecular complex could lead to important therapeutic strategies for suppression of arthritis. In order to produce analog peptides with the potential of disrupting I-A(q)- restricted antigen presentation, synthetic analog peptides were developed that contained amino acid substitutions at selected residues within CII 260-270. One of these analog peptides, A9, (CII 245-270 [s260, 261, 263]), was found to be capable of inhibiting T cell responses to CII in vitro. When DBA/1 mice, (H-2(q)), were administered this analog peptide, the incidence and severity of arthritis were significantly reduced along with the humoral immune responses to CII. Therefore, we plan to identify the amino acid residues of CII 260-270 which interact with I-A(q) and residues which interact with TcR in order to determine the role each amino acid residue plays in T cell function and to design analog peptides which are most effective in disrupting T cell function. The potential mechanism for the effectiveness of these inhibitory peptides will be investigated by i) Analyzing the lymphokine secretion profiles, (TH1 vs. TH2), generated both in vitro and in vivo when CII 260-270-reactive T cells are exposed to wild type peptide, A9 analog, or other inhibitory peptides, and ii) Characterizing the mechanism by which A9 or other inhibitory analog peptides effect signaling through the T cell receptor. Specific attention will be focused on tyrosine phosphorylation of TcR/CD3-associated proteins and turnover of phosphatidyl inositol. Insights gained from these studies will provide important lessons for approaches to designing analog peptides that may be useful in the therapy of autoimmune arthritis in humans.