Role of HLA class II genes in demyelination

描述(由申请人提供)：多发性硬化症(MS)的易感性与某些人类白细胞抗原II类基因有关，尽管对它们的确切功能的分析仍然很复杂。我们最近在缺乏内源性II类基因的新的完全II类基因敲除的MHCII-/-小鼠(由Benoist和Mathis产生)的背景下产生了人源化II类转基因小鼠(AEO)。与我们的“Abo”转基因小鼠不同，在这个新的转基因品系“AEO”中，T细胞在其细胞表面表达II类，并能递呈抗原。PLP91-110多肽可诱导HLADR3小鼠发生严重的EAE，与DR3Abo小鼠相比，AEo小鼠发病早，发病率高。此外，患有EAE的小鼠在CMS中表现出严重的炎症和脱髓鞘。因此，我们的新转基因品系模拟了人类多发性硬化症，既表现为T细胞上MHC II类分子的表达，也模拟了严重的中枢神经系统脱髓鞘。我们推测，在自身免疫性疾病中，如MS，表达II类的自身反应性CD4+T细胞可以在中枢神经系统内递送额外的髓鞘抗原，从而传播炎症反应，最终导致中枢神经系统损伤。利用这个疾病模型，我们将首先探索人类II类在疾病过程中的作用，特别是神经功能缺陷和中枢神经系统组织病理学。在中枢神经系统病理学方面，我们将评估脊髓脱髓鞘、再髓鞘和轴突丢失的程度，以及脑内炎症、神经元坏死和白质脱髓鞘的程度。接下来，我们将分析类II在脑和脊髓不同区域以及中枢神经系统浸润性细胞中的表达及其在疾病发病机制中的作用。我们还将分析CD4T细胞和CDS T细胞在EAE发病机制和调控中的作用，因为已有研究表明，它们在MS/EAE中既起致病作用，又起保护作用。接下来，我们还将分析辅助分子、共刺激分子和细胞因子在调节疾病中的作用和贡献。最后，我们将利用双转基因小鼠，研究DR和DQ基因之间的基因互补如何影响易感的HLAII类转基因小鼠的疾病发生和发展。这项提案中概述的全面研究应该能深入了解人类多发性硬化症的易感性、发病、进展、严重程度、调节和干预的作用。最后，这一新的人源化II类EAE模型可能为MS的发病机制提供新的见解。

DESCRIPTION (provided by applicant): Susceptibility to multiple sclerosis (MS) has been linked to certain HLA class II genes, although analysis of their exact function remains complicated. We have recently generated humanized class II transgenic mice (AEo) in the context of the new complete class II knockout MHCII-/- mice (produced by Benoist and Mathis) lacking all endogenous class II genes. In contrast to our "Abo" transgenic mice, in this new transgenic line "AEo", T cells express class II on their cell surface and can also present antigen. PLP91-110 peptide induced a severe EAE in HLA-DR3.AEo mice characterized by early disease onset and increased disease incidence as compared to DR3.Abo mice. Further mice with EAE showed severe inflammation and demyelination in CMS. Thus our new transgenic line simulates human MS both in form of expression of MHC class II on T cells as well as severe CNS demyelination. We hypothesize that in autoimmune diseases such as MS, auto- reactive CD4+ T cells expressing class II can present additional myelin antigen inside CNS thus propagate the inflammatory response which ultimately leads to CNS injury. Using this disease model, we will first explore role of human class II in the disease process with particular emphasis on neurological deficits and CNS histopathology. In CNS pathology, we will assess extent of demyelination, remyelination and axonal loss in spinal cord as well as the extent of inflammation, neuronal necrosis and white matter demyelination in brain. Next, we will analyze the expression of class II in different regions of brain and spinal cord as well as on CNS infiltrating cells and its role in modulating disease pathogenesis. We will also analyze role of CD4 T cells and CDS T cells both in pathogenesis as well as regulation of EAE as it has been suggested that they can play both pathogenic and protective role in MS/EAE. Next we will also analyze role and contribution of accessory molecules, costimulatory molecules, and cytokines in modulating the disease. Finally using double transgenic mice, we will study that how gene complementation between DR and DQ gene affect the disease initiation and progression in a susceptible HLA class II transgenic mice. The comprehensive studies outlined in this proposal should yield an insight into the role of HLA class II genes in predisposition, onset, progression, severity, modulation, and intervention of human multiple sclerosis. Finally, this new humanized class II model of EAE may provide new insight into the pathogenesis of MS.