INTRACELLULAR CYTOKINE PRODUCTION BY HUMAN CD4(-CELLS FROM NORMAL ANDIMMUNODEFICIENT DONORS USING DIRECTLY CONJUGATED ANTI-CYTOKINE ANTIBODIES AND 3-COLOR FLOW-CYTOMETRY() AND CD8(+) T)

Using three-colour flow cytometry, we have measured intracellular IL-2 , interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-a lpha) induced in human CD4(+) and CD8(+) T cells from normal donors an d patients with common variable immunodeficiency (CVID). Since a new r ange of directly FITC-conjugated anti-cytokine antibodies was used, co nditions were optimized for the concentration of antibody, for cell pe rmeabilization and fixation, and for the time of exposure to monensin to retain the cytokines within the cell. Kinetics of intracellular cyt okine production were measured for up to 20 h in culture with phorbol myristate acetate (PMA) and ionomycin, or with phytohaemagglutinin (PH A). Kinetic studies of activation with PMA and ionomycin show that a h igher proportion of normal CD4(+) cells can make IL-2 than the other t wo cytokines, and that there are more TNF-alpha-positive CD4(+) cells than cells with IFN-gamma. For normal CD8(+) cells the highest product ion of cytokine is of IFN-gamma (up to 50% of the cells) especially at longer rimes (10-20 h) of stimulation. For CD8(+) cells, IL-2-positiv e cells exceed those with TNF-alpha. The other mitogenic stimulus used (PHA) was grossly inferior to PMA and ionomycin in its ability to ind uce intracellular cytokines. The time of exposure to monensin was also examined. Its continuous presence in the cultures (up to a maximum of 20 h) increased the detection of IL-2-positive cells without apparent ly reducing the percentage of cytokine-positive CD4(+) or CD8(+) cells . Finally using optimal conditions, we compared cytokine production in cells from patients with the disease CVID and showed normal cellular levels of ability to produce IL-2 and TNF-alpha but significantly rais ed levels of production of IFN-gamma in both CD4(+) and CD8(+) lymphoc ytes. This suggests that the pathology of this disease may involve an excessive Th1-type response.