NOVEL MHC CLASS II CONSTRUCTS FOR TREATMENT OF EAE

MHC/肽抗原复合物与T细胞受体（TCR）之间的相互作用对于抗原特异性T细胞活化至关重要。抗原类似物可以作为T细胞活化的强大和特异性抑制剂，为过敏和自身免疫性疾病的抗原特异性免疫干预提供了合理的途径。用髓鞘碱性蛋白（MBP）或MBP肽免疫的Lewis大鼠发生实验性自身免疫性脑脊髓炎（EAE），这是一种CD4+、Th1细胞介导的中枢神经系统（CNS）脱髓鞘疾病，被用作人类疾病多发性硬化症（MS）的模型。在EAE Lewis大鼠模型中，MBP-72-89特异性T细胞主导自身免疫反应，TCR在致病性T细胞上的表达得到了很好的表征。该模型提供了一个极好的机会来测试假设，即调节MHC/肽与TCR相互作用的环境可用于控制抗原定向T细胞活化。我们最近开发了一个来自大鼠MHC II类α -1和β -1结构域的新分子家族，具有或不具有遗传关联的多肽表位。非共价和共价beta1alpha1/MBP-72-89构建体均能抑制致病性MBP-72-89反应性T细胞的活化，可用于EAE的预防和治疗。这些分子在治疗人类自身免疫性疾病中的潜力为进一步表征这些分子调节CD4+致病性T细胞的机制提供了强有力的依据。我们建议：1)对β α 1分子进行生物化学表征；2)通过直接结合研究确定beta1alpha1/peptide分子的特异性，明确TCR与beta1alpha1/peptide分子的相互作用面；3)表征β 1 α 1/肽分子的体外效应，并确定β 1 α 1/肽治疗可以改变效应细胞对抗原刺激的激活的时间框架和背景；4)表征beta1alpha1/肽分子在体内的作用，明确beta1alpha1/肽分子在体内阻断EAE诱导的机制。

The interaction between the MHC/peptide-antigen complex and the T cell receptor (TCR) is essential for antigen-specific T cell activation. Antigen analogs can act as powerful and specific inhibitors of T cell activation and provide a rational approach to antigen-specific immuno-intervention in allergies and autoimmune diseases. Lewis rats immunized with myelin basic protein (MBP) or MBP peptides develop experimental autoimmune encephalomyelitis (EAE), a CD4+, Th1 cell-mediated demyelinating disease of the central nervous system (CNS) that is used as a model for the human disease multiple sclerosis (MS). In the Lewis rat model of EAE, T cells specific for MBP-72-89 dominate the autoimmune response and TCR expression on the pathogenic T cells is well characterized. This model provides an excellent opportunity to test the hypothesis that regulating the context in which MHC/peptide interacts with TCR can be used to control antigen-directed T cell activation. We have recently developed a family of novel molecules derived from the rat MHC class II alpha-1 and beta-1 domains, with and without a genetically linked polypeptide epitope. Both the non-covalent and covalent beta1alpha1/MBP-72-89 constructs inhibited activation of pathogenic MBP-72-89 reactive T cells and could be used to prevent and treat EAE. The potential of these molecules in the treatment of human autoimmune disease provides a strong rationale to further characterize the mechanism by which these molecules regulate CD4+ pathogenic T cells. We propose to 1) Characterize the beta1alpha1 molecules biochemically; 2) Determine the specificity of the beta1alpha1/peptide molecules by direct binding studies to define the interaction surface between the TCR and beta1alpha1/peptide molecules; 3) To characterize the in vitro effects of the beta1alpha1/peptide molecules and define the time-frame and context within which beta1alpha1/peptide treatment can alter the activation of effector cells in response to antigen stimulation; and 4) To characterize the in vivo effects of the beta1alpha1/peptide molecules, with the goal of defining the mechanism by which the beta1alpha1/peptide molecules block the induction of EAE in vivo.