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

In each Rag Ϫ/Ϫ TCR transgenic model except Rag Ϫ/Ϫ MBP TCR1 transgenic mice, the percentage of naive T cells (CD45RB high , CD44 low ) found in the CNS is Ͼ80% compared with Ͻ30% in nontransgenic mice (Fig. 2) . Rag Ϫ/Ϫ MBP TCR1 transgenic mice are unique in that they appear to contain a higher percentage of CD45RB low T cells in the CNS than the other transgenic models, and consequently a lower percentage of naive T cells. Interestingly, MBP TCR1 transgenic mice on a Rag ϩ/ϩ background also differ significantly from MBP TCR2 transgenic mice in their incidence of spontaneous EAE. In a conventional animal facility, the incidence of spontaneous EAE is 45% in MBP TCR1 mice but only 11% in MBP TCR2 transgenic mice (25) .