In Situ Tolerance within the Central Nervous System as a Mechanism for Preventing Autoimmunity

Brabb, Thea; von Dassow, Peter; Ordonez, Nadia; Schnabel, Bryan; Duke, Blythe; Goverman, Joan

The data described above suggest that reducing the number of activated T cells in the periphery does not diminish trafficking to the CNS, but instead allows more naive T cells to gain entry. This hypothesis predicts that the CNS of other Rag Ϫ/Ϫ TCR transgenic mice should also contain similar numbers of T cells as the CNS of wild-type mice, and that the CNS T cells in the TCR transgenic mice should display a naive phenotype. To test these predictions, CNS T cells were isolated from two other Rag Ϫ/Ϫ TCR transgenic models that were not specific for CNS antigens. In Rag Ϫ/Ϫ LCMV and Rag Ϫ/Ϫ Ova TCR transgenic mice, the number of T cells isolated per gram of CNS tissue was again comparable to the number of T cells isolated from nontransgenic control mice (data not shown). T cells isolated from the CNS of both of these transgenic models also express low levels of CD44 and CD49d, and intermediate to high levels of CD45RB ( Fig. 2 and data not shown).