title: Direct demonstration of the infiltration of murine central nervous system by Pgp-1/CD44high CD45RB(low) CD4+ T cells that induce experimental allergic encephalomyelitis.
abstract: In experimental allergic encephalomyelitis (EAE), autoimmune T cells infiltrate the central nervous system (CNS) and initiate demyelinating pathology. We have used flow cytometry to directly analyse the migration to the CNS of MBP-reactive CD4+ T cells labelled with a lipophilic fluorescent dye (PKH2), in SJL/J mice with passively transferred EAE. Labelled cells constituted about 45% of the CNS CD4+ population at the time of EAE onset. Almost all (greater than 90%) of the PKH2-labelled CD4+ T cells from EAE CNS were blasts and were alpha/beta T cell receptor (TCR)+, CD44(Pgp-1)high, and the majority were CD45RB(low). By contrast, most PKH2-labelled CD4+ T cells in lymph nodes, although CD44high, were CD45RBhigh cells. The cells that were transferred to induce EAE were essentially similar to antigen-primed lymph node cell populations, containing less than 15% CD44high cells, and most of them were CD45RBhigh. The CD44high CD45RB(low) phenotype is characteristic of memory/effector T cells that have been activated by antigen recognition. The difference in CD45RB expression between CNS and LN could therefore reflect differential exposure and/or response to antigen. Consistent with this, PKH2-labelled CD4+ cells isolated from the CNS were responsive to MBP in vitro, whereas PKH2+ CD4+ cells from lymph nodes showed almost undetectable responses. In control experiments in which ovalbumin (OVA)-reactive T cells were transferred, a small number of fluorescent-labelled CD4+ T cells were also detected in CNS, but there were very few blasts, and these remained CD45RBhigh. These results argue for induction of the memory/effector phenotype of CD4+ T cells, and their selective retention in the CNS, as a consequence of antigen recognition.
authors.affiliation: Department of Medicine, Montreal Neurological Institute, McGill University, Quebec, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Zeine
authors.forename: T
authors.initials: T
authors.lastname: Owens
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D015704:CD4 Antigens / Q000032:analysis*; D002465:Cell Movement; D002469:Cell Separation; D002490:Central Nervous System / Q000276:immunology*; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology*; D005260:Female; D005456:Fluorescent Dyes; D006649:Histocompatibility Antigens / Q000032:analysis*; D017493:Leukocyte Common Antigens; D008198:Lymph Nodes / Q000166:cytology / Q000502:physiology; D051379:Mice; D004676:Myelin Basic Protein / Q000494:pharmacology; D009930:Organic Chemicals; D010047:Ovalbumin / Q000494:pharmacology; D010641:Phenotype; D016201:Receptors, Lymphocyte Homing / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology* / Q000637:transplantation
chemical_list: D015703:Antigens, CD; D015704:CD4 Antigens; D005456:Fluorescent Dyes; D006649:Histocompatibility Antigens; D004676:Myelin Basic Protein; D009930:Organic Chemicals; C068241:PKH-2; D016201:Receptors, Lymphocyte Homing; D010047:Ovalbumin; D017493:Leukocyte Common Antigens