title: Generation of CD28- cells from long-term-stimulated CD8+CD28+ T cells: a possible mechanism accounting for the increased number of CD8+CD28- T cells in HIV-1-infected patients.
abstract: According to CD28 molecule expression, CD8+ T cells can be classed as CD28bright, CD28dim, and CD28-. The CD28dim T cells were found to derive from mitogenic stimulated CD28-T cells but also from CD28bright T cells through a mechanism of CD28 down-modulation. Moreover, after prolonged in vitro interleukin-2 stimulation, clonal CD28bright, cells showed a CD28dim expression before further evolution to a stable CD28-phenotype. This loss was concomitant with the disappearance of CD28 mRNA. A study of the cytokine production pattern revealed that CD28dim and CD28- T cell clones produced similar levels of type 1 and type 2 cytokines, which differed from those produced by the CD28bright T cell clones. A high percentage of CD28dim and CD28- cells, with similarities in their cytokine production pattern, were found in the blood samples of HIV-infected patients, as compared to healthy donors. The CD28 down-modulation may account for the increased number of CD8+CD28- T cells in HIV-infected patients.
authors.affiliation: Institute of Microbiology, Department of Experimental and Applied Medicine, Brescia Medical School, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Fiorentini
authors.forename: F
authors.initials: F
authors.lastname: Malacarne
authors.forename: D
authors.initials: D
authors.lastname: Ricotta
authors.forename: S
authors.initials: S
authors.lastname: Licenziati
authors.forename: A A
authors.initials: AA
authors.lastname: Solis
authors.forename: S
authors.initials: S
authors.lastname: Ausenda
authors.forename: M
authors.initials: M
authors.lastname: De Francesco
authors.forename: E
authors.initials: E
authors.lastname: Garrafa
authors.forename: A
authors.initials: A
authors.lastname: Simonini
authors.forename: L
authors.initials: L
authors.lastname: Imberti
authors.forename: A
authors.initials: A
authors.lastname: Balsari
authors.forename: A
authors.initials: A
authors.lastname: Turano
authors.forename: A
authors.initials: A
authors.lastname: Caruso
mesh_terms: D000328:Adult; D018106:CD28 Antigens / Q000096:biosynthesis* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002999:Clone Cells; D005260:Female; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism
chemical_list: D018106:CD28 Antigens; D007378:Interleukins; D007371:Interferon-gamma