The meninges, comprising the leptomeninges (pia and arachnoid layers) and the pachymeninx (dura layer), participate in central nervous system (CNS) autoimmunity, but their relative contributions remain unclear. Here we report on findings in animal models of CNS autoimmunity and in patients with multiple sclerosis, where, in acute and chronic disease, the leptomeninges were highly inflamed and showed structural changes, while the dura mater was only marginally affected. Although dural vessels were leakier than leptomeningeal vessels, effector T cells adhered more weakly to the dural endothelium. Furthermore, local antigen-presenting cells presented myelin and neuronal autoantigens less efficiently, and the activation of autoreactive T cells was lower in dural than leptomeningeal layers, preventing local inflammatory processes. Direct antigen application was required to evoke a local inflammatory response in the dura. Together, our data demonstrate an uneven involvement of the meningeal layers in CNS autoimmunity, in which effector T cell trafficking and activation are functionally confined to the leptomeninges, while the dura remains largely excluded from CNS autoimmune processes.

脑膜，包括软脑膜（软脑膜和蛛网膜层）和硬脑膜（硬脑膜层），参与中枢神经系统 (CNS) 自身免疫，但它们的相对贡献仍不清楚。在这里，我们报告了 CNS 自身免疫动物模型和多发性硬化症患者的研究结果，在这些患者中，在急性和慢性疾病中，软脑膜高度发炎并显示出结构变化，而硬脑膜仅受到轻微影响。尽管硬脑膜血管比软脑膜血管更渗漏，但效应 T 细胞与硬脑膜内皮的粘附更弱。此外，局部抗原呈递细胞呈递髓鞘和神经元自身抗原的效率较低，并且在硬脑膜中自身反应性 T 细胞的活化低于软脑膜层，从而阻止了局部炎症过程。需要直接应用抗原以在硬脑膜中引起局部炎症反应。总之，我们的数据表明脑膜层在 CNS 自身免疫中的参与不均衡，其中效应 T 细胞的运输和激活在功能上仅限于软脑膜，而硬脑膜在很大程度上仍被排除在 CNS 自身免疫过程之外。