title: Evidence that human CD8+CD45RA+CD27- cells are induced by antigen and evolve through extensive rounds of division.
abstract: We recently showed that circulating human CD8(+) effector cells have a CD45RA+CD27(-) membrane phenotype. In itself this phenotype appeared to pose a paradox: CD45RA, a marker expressed by unprimed cells, combined with absence of CD27, characteristic for chronically stimulated T cells. To investigate whether differentiation towards the CD45RA+CD27(-) phenotype is dependent on antigenic stimulation and involves cellular division, TCR Vbeta usage and telomeric restriction fragment (TRF) length were analyzed within distinct peripheral blood CD8(+) subsets. FACS analysis showed that the TCR Vbeta repertoire of CD8(+)CD45RA+CD27(-) cells differed significantly from that of unprimed CD8(+)CD45RA+CD27(+) cells. Moreover, in two out of six individuals large expansions of particular Vbeta families were observed in the CD8(+)CD45RA+CD27(-) subset. CDR3 spectrotyping and single-strand confirmation analysis revealed that within the CD8(+)CD45RA+CD27(-) population most of the 22 tested Vbeta families were dominated by oligoclonal expansions. The mean TRF length was found to be 2.3+/-1.0 kb shorter in the CD8(+)CD45RA+CD27(-) subset compared with the unprimed CD8(+)CD45RA+CD27(+) population, but did not differ substantially from that of memory type, CD8(+)CD45RA-CD27(+) T cells. These findings indicate that the CD8(+)CD45RA+CD27(-) cytotoxic effector population consists of antigen-induced, clonally expanded cells and confirm that the expression of CD45RA is not a strict marker of antigen non-experienced T cells.
authors.affiliation: Department of Clinical Viro-Immunology, Central Laboratory of the Netherlands Red Cross Blood Transfusion Service (CLB) and Laboratory of Experimental and Clinical Immunology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Hamann
authors.forename: S
authors.initials: S
authors.lastname: Kostense
authors.forename: K C
authors.initials: KC
authors.lastname: Wolthers
authors.forename: S A
authors.initials: SA
authors.lastname: Otto
authors.forename: P A
authors.initials: PA
authors.lastname: Baars
authors.forename: F
authors.initials: F
authors.lastname: Miedema
authors.forename: R A
authors.initials: RA
authors.lastname: van Lier
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D016130:Immunophenotyping; D017493:Leukocyte Common Antigens / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D016615:Telomere / Q000276:immunology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism
chemical_list: D018984:Epitopes, T-Lymphocyte; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D017493:Leukocyte Common Antigens