CD62Lhigh Treg cells with superior immunosuppressive properties accumulate within the CNS during remissions of EAE

The role of regulatory T cell populations within the CNS in the regulation of CNS-autoimmunity is controversial. We show that during recovery from relapsing remitting experimental autoimmune encephalomyelitis, regulatory T cells accumulate within the CNS that express high levels of CD62L. These CD62Lhigh Treg cells express increased amounts of CTLA-4, ICOS and TGF-β and are more potent than CD62Llow Treg cells in suppressing proliferation and inducing apoptosis in effector T cells. CD62Lhigh Treg cells thus represent a population of Treg cells that display superior immunosuppressive properties and accumulate in the CNS during recovery from CNS-autoimmunity.