Modulation of EAE with ligand-activated NKT cells

描述（由申请人提供）：多发性硬化症（MS）是一种中枢神经系统（CNS）慢性炎症性疾病，推测其病因为自身免疫性。实验性自身免疫性脑脊髓炎（EAE）常被用作MS的动物模型。EAE可以通过注射CNS蛋白或肽与佐剂一起在易感小鼠品系中诱导。大多数研究表明，髓鞘特异性T辅助1型（Th 1）细胞分泌IFN-γ和TNF-α介导EAE和MS，而髓鞘特异性Th 2细胞产生IL-4和IL-10发挥调节作用。动物模型的研究表明，将免疫应答从Th 1-显性应答调节为Th 2-显性应答可以有效地保护小鼠免受EAE的侵害。自然杀伤T（NKT）细胞是共表达常规T细胞和NK细胞的特征性表面标志物的T淋巴细胞的子集。NKT细胞的不变的Valpha 14 T细胞受体对与非多态性MHC I类蛋白CD 1d结合的糖脂抗原具有特异性。虽然NKT细胞的精确免疫功能仍然未知，但这些细胞涉及针对病原体和肿瘤的保护性免疫应答以及自身免疫应答的调节。在PI实验室进行的先前工作表明，用糖脂α-半乳糖神经酰胺（α-GalCer）对NKT细胞的配体特异性激活极化了小鼠中产生Th 2细胞因子的适应性免疫应答。这些研究结果表明，α-GalCer可以抑制Th 1导向的免疫反应，提供了一种替代的方式来抑制免疫反应，导致病理器官特异性自身免疫性疾病，如MS。事实上，我们的初步结果表明，α-GalCer防止诱导EAE易感小鼠。基于我们已发表的研究结果和初步结果，该资助申请的中心假设是NKT细胞代表了EAE和MS免疫调节的新型靶细胞类型。目的1探讨配体激活的CD 1d抑制的NKT细胞调节EAE的机制。目的2将评估由α-GalCer赋予的疾病保护是否是主动抑制过程。目的3将确定α-GalCer与其他免疫调节剂预防EAE疾病的潜在协同作用。目的4将评估α-Ga 1Cer类似物保护小鼠免受EAE的能力。这些研究将有助于更好地了解NKT细胞的免疫功能和介导自身免疫的机制。在该项目完成时，我们预计已经确定了一套试剂（NKT细胞配体，细胞因子，阻断抗体），可用于特异性激活或抑制NKT细胞的不同效应子功能。这些试剂将允许在体内选择性激活不同的适应性免疫应答，这可以用于MS和其他人类自身免疫性疾病的治疗干预。

DESCRIPTION (provided by applicant): Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) with a presumed autoimmune etiology. Experimental autoimmune encephalomyelitis (EAE) is frequently used as an animal model of MS. EAE can be induced in susceptible mouse strains by injection of CNS proteins or peptides together with adjuvants. Most studies have indicated that myelin-specific T helper type 1 (Th1) cells secreting IFN-gamma and TNF-alpha mediate EAE and MS. whereas myelin-specific Th2 cells producing IL-4 and IL-10 play a regulatory role. Studies with animal models have demonstrated that modulation of immune responses from a Th1-dominant to a Th2-dominant response can effectively protect mice against EAE. Natural killer T (NKT) cells are a subset of T lymphocytes that co-express surface markers characteristic of conventional T cells and NK cells. The invariant Valpha14 T cell receptor of NKT cells is specific for glycolipid antigens bound with the non-polymorphic MHC class I-like protein CD1d. While the precise immunological function of NKT cells remains unknown, these cells have been implicated in protective immune responses against pathogens and tumors, and in the regulation of autoimmune responses. Prior work conducted in the PI's laboratory has shown that ligand-specific activation of NKT cells with the glycolipid alpha-galactosylceramide (alpha-GalCer) polarizes adaptive immune responses for production of Th2 cytokines in mice. These findings suggest that alpha-GalCer can inhibit Th1 -oriented immune responses, providing an alternative way to suppress immune responses that cause pathology in organ-specific autoimmune diseases such as MS. Indeed, our preliminary results have revealed that alpha-GalCer prevents the induction of EAE in susceptible mice. Based on our published findings and preliminary results, the central hypothesis of this grant application is that NKT cells represent a novel target cell type for immunomodulation of EAE and MS. We will test this hypothesis in four Specific Aims. Aim 1 will investigate the mechanism by which ligand-activated CD1d-resticted NKT cells modulate EAE. Aim 2 will evaluate whether disease protection conferred by a-GalCer is an active suppressive process. Aim 3 will determine the potential synergy of alpha-GalCer with other immunomodulatory reagents for prevention of EAE disease. Aim 4 will evaluate the ability of alpha-Ga1Cer analogues to protect mice against EAE. These studies will provide a better understanding of the immunological functions of NKT cells and the mechanisms that mediate autoimmunity. At the completion of this project, we expect to have identified a set of reagents (NKT cell ligands, cytokines, blocking antibodies) that can be utilized to specifically activate or inhibit different effector functions of NKT cells. These reagents will permit the selective activation of distinct adaptive immune responses in vivo, which could be exploited for therapeutic intervention in MS and other human autoimmune diseases.