title: CD45RA-expressing memory/effector Th cells committed to production of interferon-gamma lack expression of CD31.
abstract: It has been considered before that human naive and memory/effector CD4+ T-cells cannot be subdivided solely according to the differential expression of CD45 isoforms. By the lack of expression of CD31 we have identified a subset of CD4+ CD45RA+ CD31- cells which show distinct features of antigen-experienced Th1 cells. Short term stimulation of highly purified human peripheral blood CD4+ T-cells with PMA/ionomycin, followed by the cytometric analysis of intracellular cytokines, showed that a minor subpopulation of CD4+ CD45RA+ CD45RO- cells is able to produce interferon-gamma (IFN-gamma) rapidly, a characteristic of antigen-experienced Th1 cells. Whereas among CD45RA+ CD4+ T-cells both CD31+ and CD31- subsets produce interleukin-2 (IL-2) upon PMA/ionomycin stimulation, only the CD31- subpopulation is able to produce IFN-gamma. Thus, our phenotypic and functional characterization of CD45RA+ CD45RO- Th cells shows that CD45RA+ CD45RO- cells do not represent a homogeneous population of antigen-unexperienced, naive T-cells. We speculate that a certain subset of human CD4+, CD45RO+ memory T-cells reverts to expression of the CD45RA isoform, and that this subset can be identified by the lack of CD31 expression.
authors.affiliation: Institute for Genetics, University of Cologne, Germany. athiel@genetik.uni-koeln.de
authors.forename: A
authors.initials: A
authors.lastname: Thiel
authors.forename: J
authors.initials: J
authors.lastname: Schmitz
authors.forename: S
authors.initials: S
authors.lastname: Miltenyi
authors.forename: A
authors.initials: A
authors.lastname: Radbruch
mesh_terms: D000818:Animals; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis*; D015759:Ionomycin / Q000494:pharmacology; D017493:Leukocyte Common Antigens / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000096:biosynthesis*; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology*
chemical_list: D008934:Mitogens; D010835:Phytohemagglutinins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D015759:Ionomycin; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens