title: CD8+ T cells primed in the periphery provide time-bound immune-surveillance to the central nervous system.
abstract: After vaccination, memory CD8(+) T cells migrate to different organs to mediate immune surveillance. In most nonlymphoid organs, following an infection, CD8(+) T cells differentiate to become long-lived effector-memory cells, thereby providing long-term protection against a secondary infection. In this study, we demonstrated that Ag-specific CD8(+) T cells that migrate to the mouse brain following a systemic Listeria infection do not display markers reminiscent of long-term memory cells. In contrast to spleen and other nonlymphoid organs, none of the CD8(+) T cells in the brain reverted to a memory phenotype, and all of the cells were gradually eliminated. These nonmemory phenotype CD8(+) T cells were found primarily within the choroid plexus, as well as in the cerebrospinal fluid-filled spaces. Entry of these CD8(+) T cells into the brain was governed primarily by CD49d/VCAM-1, with the majority of entry occurring in the first week postinfection. When CD8(+) T cells were injected directly into the brain parenchyma, cells that remained in the brain retained a highly activated (CD69(hi)) phenotype and were gradually lost, whereas those that migrated out to the spleen were CD69(low) and persisted long-term. These results revealed a mechanism of time-bound immune surveillance to the brain by CD8(+) T cells that do not reside in the parenchyma.
authors.affiliation: National Research Council of Canada-Institute for Biological Sciences, Ottawa, Ontario K1A 0R6, Canada.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Young
authors.forename: Susanne
authors.initials: S
authors.lastname: Maclean
authors.forename: Renu
authors.initials: R
authors.lastname: Dudani
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Krishnan
authors.forename: Subash
authors.initials: S
authors.lastname: Sad
mesh_terms: D000818:Animals; D001921:Brain / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology / Q000637:transplantation; D002465:Cell Movement / Q000276:immunology; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000134:cerebrospinal fluid / Q000276:immunology; D005260:Female; D007156:Immunologic Memory; D007157:Immunologic Surveillance; D016130:Immunophenotyping; D008089:Listeria monocytogenes / Q000276:immunology; D008088:Listeriosis / Q000134:cerebrospinal fluid* / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic
chemical_list: D018984:Epitopes, T-Lymphocyte