ANALOG PEPTIDES EFFECTS ON COLLAGEN INDUCED ARTHRITIS

胶原性关节炎(CIA)是一种实验性自身免疫性关节炎 对遗传易感品系小鼠进行免疫诱导 II型胶原(CII)。它与人类有几个重要的特征 类风湿关节炎。它的特征是对CII的免疫反应， 包括T细胞的激活和致关节炎的产生 最终导致滑膜炎的自身抗体，以及 释放能破坏组织的降解酶。以前的工作在 我们的实验室已经确定了II型胶原的一个区域，CII260-270， 作为I-CII免疫应答中的免疫优势T细胞表位 A(Q)荷瘤小鼠。T细胞的激活需要首先形成 抗原肽与主要组织相容性复合体的结合 (MHC)分子。这些复合体随后被T细胞识别 抗原特异性T细胞受体(TCR)。这种三位一体结构的形成 分子复合体是T细胞活化过程中必不可少的初始事件 细胞和随后产生的致关节炎抗体，以及 关节炎的发展。因此，开发一种扰乱 在三分子复合体的背景下激活T细胞可以 导致重要的治疗策略，以抑制关节炎。在……里面 为了产生有可能破坏I-A(Q)的模拟多肽- 限制抗原提呈，合成类似肽被开发出来 在CII内的选定残基上含有氨基酸取代 260-270。这些模拟多肽之一，A9，(CII 245-270[S260,261,263])， 在体外能够抑制T细胞对CII的反应。 当给DBA/1小鼠(H-2(Q))注射该模拟肽时， 关节炎的发病率和严重程度随着 对CII的体液免疫应答。因此，我们计划确定 CII260-270与I-A(Q)和残基相互作用的氨基酸残基 它们与TCR相互作用，以确定每个氨基酸的作用 残基在T细胞功能中发挥作用，并设计模拟多肽，这些模拟多肽 在扰乱T细胞功能方面最为有效。可能的机制是 这些抑制肽的有效性将通过i)进行研究。 分析淋巴因子分泌情况，(TH1与TH2)产生了这两个 CII 260-270反应性T细胞暴露于野生环境中的体内外研究 类肽、A9类似物或其他抑制性多肽，以及ii) 表征A9或其他抑制类似物的机制 多肽通过T细胞受体影响信号传递。特别关注 将专注于TCR/CD3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 这可能对人类自身免疫性关节炎的治疗有用。

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.