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

• Published in: Journal of leukocyte biology Vol. 65; no. 5; pp. 641 - 648
• Main Authors: Fiorentini, Simona, Malacarne, Fabio, Ricotta, Doris, Licenziati, Stefano, Solis, Adakatia Armenta, Ausenda, Sabrina, De Francesco, Maria, Garrafa, Emirena, Simonini, Andrea, Imberti, Luisa, Balsari, Andrea, Turano, Adolfo, Caruso, Arnaldo
• Format: Journal Article
• Language: English
• Published: United States Society for Leukocyte Biology 01.05.1999
• Subjects: Adult; AIDS/HIV; CD28 Antigens - biosynthesis; CD28 Antigens - immunology; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - metabolism; cellular differentiation; clonal expansion; Clone Cells; cytokines; Female; HIV Infections - immunology; HIV-1 - immunology; Humans; Immunophenotyping; Interferon-gamma - metabolism; Interleukins - metabolism; Lymphocyte Activation - immunology; Male; T-Lymphocyte Subsets - immunology; T-Lymphocyte Subsets - metabolism
• ISSN: 0741-5400; 1938-3673
• DOI: 10.1002/jlb.65.5.641

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 CD28bnght 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. J. Leukoc. Biol. 65: 641–648; 1999.