Antigen-specific T cell trafficking into the central nervous system

The initiation step of cell-mediated immune responses in the central nervou s system (CNS) involves the trafficking of the antigen-specific T cells int o the blain. To study this trafficking, we developed an in vivo system for studying antigen-specific responses in the CNS. In this assay, T cell recep tor (TCR) transgenic mice having 95% of T cells specific for a defined anti gen-pigeon cytochrome c (PCC) were cannulated intraventricularly for PCC an tigen infusion and cerebrospinal fluid (CSF) sampling. Upon PCC infusion in to the CNS, the number of alpha/beta TCR+ V beta 3(+) Mac1(-) cells in the CSF was characterized. We found that infusion of antigen into the CSF induc ed an increased number of antigen-specific T cells in the CNS and activatio n of antigen-specific T cells in the peripheral blood. Hence, the drainage of CNS antigen into the periphery might play an important role in sustainin g autoimmune reactivity in CNS inflammatory diseases. (C) 2000 Elsevier Sci ence B.V. All rights reserved.