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.
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.
Fiorentini
S
S
Institute of Microbiology, Department of Experimental and Applied Medicine, Brescia Medical School, Italy.
Malacarne
F
F
Ricotta
D
D
Licenziati
S
S
Solis
A A
AA
Ausenda
S
S
De Francesco
M
M
Garrafa
E
E
Simonini
A
A
Imberti
L
L
Balsari
A
A
Turano
A
A
Caruso
A
A
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
D018106:CD28 Antigens; D007378:Interleukins; D007371:Interferon-gamma