Figure 1.

Role of the gut in the CNS autoimmunity. CNS-autoreactive Th1 and Th17 cells are activated in the lymph nodes (1). They migrate into the CNS where they initiate inflammatory response imposing destruction of the CNS tissue (2). They also migrate into the gut (3), where they can be re-differentiated to Treg which counteract the inflammation in the CNS (4). However, they can also be supported by the gut environment in their encephalitogenicity (5). Finally, it is proposed that encephalitogenic Th cells might be initially activated in the gut by the process of molecular mimicry, as they cross-react with gut microbial antigens (6).