ANALOG PEPTIDES IN COLLAGEN-INDUCED ARTHRITIS

胶原蛋白引起的关节炎中的类似肽

• 批准号: 6050854
• 负责人: Linda K. Myers
• 金额: $ 19.94万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-24 至 2005-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6050854
• 关键词: MHC class II antigen; T cell receptor; antiarthritic agent; arthritis therapy; autoimmune disorder; collagen; disease /disorder model; drug design /synthesis /production; genetic susceptibility; genetically modified animals; helper T lymphocyte; interleukin 10; interleukin 4; laboratory mouse; leukocyte activation /transformation; nonhuman therapy evaluation; peptide analog; protein sequence; protein structure function; rheumatoid arthritis; synthetic peptide

Collagen-induced arthritis (CIA) is an experimental model of autoimmune arthritis induced by immunization of susceptible strains of mice with type II collagen (CII). Our recent studies using HLA-DR transgenic (Tg) mice expressing HLA class II molecules associated with susceptibility to rheumatoid arthritis (RA) reveal that DR1 (DRB1*0101) and DR4 (DRB1*0401) can bind and present peptides derived from human (h) CII, and that mice bearing these transgenic DR molecules are susceptible to CIA. The immune response to hCII and arthritis can be down regulated by an analog peptide of CII, A12, CII 256-276 (F263->N, E266->D), when it is co-administered at the time of immunization with hCII. Human CII- sensitized spleen and lymph node cells from DR Tg mice produce increased amounts of IL-4 and IL-10 when cultured with Al2 in comparison to cells cultured with the wild-type CII peptide (CII 256-276). These observations suggest that the suppressive effect of A12 on immune response to CII and CIA in these DR Tg mice is mediated by a shift in the cytokine profile, from that of a Thl to a Th2. However, the mechanism(s) whereby the shift is brought about is not known. Al2 contains two amino acid substitutions as compared to the wild-type CII peptide. The substitutions are of two types, a) residue 263 that participates in peptide binding to the DR molecule, and b) residue 266 that interacts with the TCR. The hypothesis to be tested in this application is that the A12 effect on CIA is mediated through polarization of the specific immune response to a predominant Th2 profile, and that this polarization is caused by changes in the affinity between either DR and peptide or DR/peptide interaction with the TCR leading to altered T cell signaling and, consequently, the production of cytokines. We, therefore, plan to: 1) Identify the structural characteristics of the analog peptide Al2 that mediate its modulation of the immune response to CIIl and CIA in DR Tg mice; 2) Determine whether encoding the Al2 substitutions within the triple helical CII molecule increases the efficacy in inhibiting the autoimmune response in CIA; 3) Determine whether the suppression of CIA produced by A12 administration is dependent on IL-l0 or IL-4 secretion; and 4) Determine the mechanism by which Al2 alters T cell function by analyzing signaling pathways involved in T cell activation. Information gained from these studies will provide important insight for the design of novel therapeutic approaches that may prove beneficial in the treatment of autoimmune arthritis in humans.

胶原诱导的关节炎（CIA）是通过用II型胶原（CII）免疫易感品系的小鼠诱导的自身免疫性关节炎的实验模型。我们最近使用表达与类风湿性关节炎（RA）易感性相关的HLA II类分子的HLA-DR转基因（Tg）小鼠的研究表明，DR 1（DRB 1 *0101）和DR 4（DRB 1 *0401）可以结合并呈递来自人（h）CII的肽，并且携带这些转基因DR分子的小鼠对CIA易感。当在免疫时与hCII共施用CII、A12、CII 256-276（F263->N，E266->D）的类似肽时，对hCII和关节炎的免疫应答可被其下调。与用野生型CII肽（CII 256-276）培养的细胞相比，当用A12培养时，来自DR Tg小鼠的人CII致敏的脾和淋巴结细胞产生增加量的IL-4和IL-10。这些观察结果表明，A12对这些DR Tg小鼠中对CII和CIA的免疫应答的抑制作用是由细胞因子谱从Th 1到Th 2的转变介导的。然而，引起这种转变的机制尚不清楚。与野生型CII肽相比，A12含有两个氨基酸取代。取代有两种类型，a）参与肽与DR分子结合的残基263，和B）与TCR相互作用的残基266。在本申请中待检验的假设是，A12对CIA的作用是通过特异性免疫应答极化至主要的Th 2谱来介导的，并且这种极化是由DR和肽之间的亲和力的变化或DR/肽与TCR的相互作用引起的，从而导致改变的T细胞信号传导，并因此产生细胞因子。因此，我们计划：1）鉴定在DR Tg小鼠中介导其对CII和CIA的免疫应答的调节的类似肽A1 2的结构特征; 2）确定在三螺旋CII分子内编码A1 2取代是否增加抑制CIA中的自身免疫应答的功效; 3）确定A12给药产生的CIA抑制是否依赖于IL-10或IL-4分泌;和4）通过分析参与T细胞活化的信号通路来确定Al 2改变T细胞功能的机制。从这些研究中获得的信息将为设计新的治疗方法提供重要的见解，这些方法可能证明对治疗人类自身免疫性关节炎有益。