Homing of T cells to the central nervous system throughout the course of relapsing experimental autoimmune encephalomyelitis in Thy-1 congenic mice.

Chronic relapsing experimental allergic encephalomyelitis (EAE) was induced in Thy-1.1 congenic SJL/J mice by the adoptive transfer of myelin basic protein (MBP)-responsive lymph node cells from Thy-1.2 SJL/J mice. The Thy-1 congenic mouse strain was constructed on the SJL (Thy-1.2) background by the initial cross with the AKR (Thy-1.1) strain and does not reject Thy-1.2+ T cells. Quantitative immunocytochemical analysis of the central nervous system (CNS) of Thy-1.1 recipients showed preferential trafficking of Thy-1.2+ T cells to the meninges and white matter, beginning prior to onset of clinical signs. At 7 days post-transfer (dpt), Thy-1.2+ donor cells constituted 2.5% of the infiltrating cells and reached peak values (ca. 10%) during the first attack. At later stages (up to ten relapses), Thy-1.2+ T cells constituted 2-5% of the infiltrate. In control mice injected with irrelevant antigen-stimulated Thy-1.2+ T cells, only the occasional Thy-1.2+ T cell could be demonstrated up to 14 dpt. This is the first study showing unequivocally the presence of MBP-stimulated, adoptively transferred T cells within the CNS of recipients throughout the course of EAE, particularly during later relapsing stages. These results indicate that the persistent presence of antigen-specific T cells may be required for the recruitment of non-CNS antigen-responsive immune cells.