title: CD45RA(bright)/CD11a(bright) CD8+ T cells: effector T cells.
abstract: An important aspect of peripheral T cell development is the differentiation from naive into memory cells. To distinguish naive from memory cells, CD45RA and CD11a are commonly used: CD45RA+ or CD11a(dim) T cells are regarded as naive, while CD45RA- or CD11a(bright) T cells are thought to be of memory type. There is, however, a CD8+ T cell subset which is CD45RA+ and at the same time CD11a(bright). It increases with age and in patients with systemic viral infections, though its functional role in the immune response is unknown. In the present study, we give evidence that this subset is related to memory-like T cells as it produces IFN-gamma and tumor necrosis factor-alpha, contains high levels of perforin, and expresses CD95 in the same way as memory-type CD45RA-/CD11a(bright) CD8+ T cells. Since it contains a high percentage of CD28- and CD57+ cells, is increased in size and granularity, and is transiently expressed following in vitro stimulation of naive CD8+ T cells, we speculate that this subset mainly represents recently activated effector T cells that are able to interact with CD80 and CD86 (B7-1 and B7-2 respectively) negative tissue cells.
authors.affiliation: Institute of Medical Immunology, University Hospital Charité, Campus Mitte, Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Höflich
authors.forename: W D
authors.initials: WD
authors.lastname: Döcke
authors.forename: A
authors.initials: A
authors.lastname: Busch
authors.forename: F
authors.initials: F
authors.lastname: Kern
authors.forename: H D
authors.initials: HD
authors.lastname: Volk
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology; D006801:Humans; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis; D017493:Leukocyte Common Antigens / Q000096:biosynthesis* / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000235:genetics* / Q000276:immunology; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D015703:Antigens, CD; D016169:Lymphocyte Function-Associated Antigen-1; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D014409:Tumor Necrosis Factor-alpha; D054353:Perforin; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens