Differential production of IFN-gamma, analyzed at the single-cell level, by specific subsets of human NK and T cells from healthy and HIV(+) subjects.
BACKGROUND
Interferon gamma is a cytokine that plays a central role in immunity, and is physiologically secreted by T and NK cells under appropriate stimuli during the immune response. By means of flow cytometry, we performed a single cell analysis of interferon gamma producing NK cells and their surface phenotype in normal and HIV(+) individuals that show several defects of cytokine production and cellular immunity.


METHODS
PBMC or purified NK cells were stimulated for 1-12 h with PMA/ionomycin in the presence of monensin, subsequently stained for surface CD56 and CD3 or CD8, and for intracytoplasmic IFN-gamma, and analysed by flow cytometry.


RESULTS
Our results show that CD56(+) NK cells are more efficient interferon gamma producers than T cells. Moreover, within the CD56(+) NK cell population, those that co-express low density CD8 are the best producers. Finally, we show that NK cells during HIV infection are more massively recruited to interferon gamma production than those from normal subjects.


CONCLUSIONS
Both in the normal and HIV(+) subjects, a higher percentage of NK cells than T cells can produce IFN-gamma although differences can be identified within the NK cells subset in terms of IFN-gamma production. The production of IFN-gamma is fully achievable in the HIV(+) subjects, which is consistent with their elevated plasmatic levels of the cytokine. The possibility that NK cells that produce interferon gamma could represent a functionally distinct population committed to the production of this cytokine, is discussed.
Vitale
M
M
Department of Biomedical Sciences and Biotechnologies, Division of Human Anatomy, University of Brescia, Brescia, Italy. vitale@med.unibs.it
Caruso
A
A
Licenziati
S
S
Rodella
L
L
Fiorentini
S
S
Zauli
G
G
Castelli
F
F
Manzoli
F A
FA
Turano
A
A
D015703:Antigens, CD / Q000032:analysis; D017252:CD3 Complex / Q000032:analysis; D019002:CD56 Antigen / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D002478:Cells, Cultured; D005434:Flow Cytometry / Q000379:methods; D018023:HIV Seronegativity / Q000276:immunology*; D006679:HIV Seropositivity / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D015759:Ionomycin / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D007700:Kinetics; D008213:Lymphocyte Activation; D008985:Monensin / Q000494:pharmacology; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate
D015703:Antigens, CD; D017252:CD3 Complex; D019002:CD56 Antigen; D016827:CD8 Antigens; D015759:Ionomycin; D007371:Interferon-gamma; D008985:Monensin; D013755:Tetradecanoylphorbol Acetate