COLLAGEN PEPTIDES AND SUPPRESSION OF COLLAGEN ARTHRITIS

描述：(改编自申请人的摘要)-申请人之前在CIA小鼠模型上的工作表明，CB11胶原II型多肽在残基245-270(A2肽)中包含这种诱导的活性部位，并模拟了类似的多肽A9，其中有三个氨基酸的取代，当与II型胶原(CII)联合使用时，或在诱导疾病后，A9可以降低关节炎的严重程度。其中两个氨基酸260和263参与多肽与MHC分子的结合，残基261与T细胞受体(TCR)相互作用。进一步的初步数据表明，与A2肽相比，当A9肽攻击时，II型胶原致敏的脾和淋巴结细胞产生更多的白介素4(IL-4)和白介素10(IL-10)。在本应用中要检验的假设是，A9对CIA的影响是通过对以Th2为主的特异性免疫反应的极化来介导的，这种极化是由于MHC与多肽之间的亲和力或MHC/多肽与TCR之间的相互作用的变化导致T细胞信号的改变，从而产生细胞因子。其具体目的是：1)确定A9模拟肽的结构特征，它介导了对CII和CIA免疫反应的调节；2)确定编码三螺旋CII中的A9取代是否增加了抑制CIA自身免疫反应的有效性；3)确定A9对CIA的抑制是否依赖于IL-10或IL-4的分泌；以及4)通过分析T细胞激活所涉及的信号通路，确定A9改变T细胞功能的机制。

DESCRIPTION: (Adapted from the applicant's abstract) - Prior work of the applicant on the CIA mouse model demonstrated that the CB11 collagen II peptide contained the active site for this induction in residues 245-270 (A2 peptide), and modeled an analog peptide, A9, with substitutions in three amino acids, which can downregulate the severity of arthritis when co-administered with Collagen II(CII), or after induction of the disease. Two of the amino acids, 260 and 263 participate in peptide binding to the MHC molecule and residue 261 interacts with the T-cell receptor (TCR). Further preliminary data indicate that Collagen II-sensitized spleen and lymph node cells produce increased amounts of Interleukin-4 (IL-4) and Interleukin-10 (IL-10) when challenged with the A9 peptide as compared to the A2 peptide. The hypothesis to be tested in this application is that the A9 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 MHC and peptide or MHC/peptide interaction with the TCR leading to altered T cell signaling and, consequently, the production of cytokines. The specific aims are: 1) To identify the structural characteristics of the analog peptide A9 that mediate its modulation of the immune response to CII and CIA; 2) determine whether encoding the A9 substitutions within the triple helical CII increases the efficacy in inhibiting the autoimmune response in CIA; 3) determine whether the suppression of CIA produced by A9 administration is dependent on IL-10 or IL-4 secretion, and 4) determine the mechanism by which A9 alters T cell function by analyzing signaling pathways involved in T cell activation.