Phenotypic changes in cytokine-driven DC when cultured in the presence of TNFα detected by a panel of antihuman FITC- or PE-labeled antibodies and FACS analysis. PBMC were cultured in XVIVO-15 serum-free medium containing GM-CSF and IL-4 for 7 days. TNFα was then added at day 7 and the cultures were allowed to proceed for an additional 7-day period. When compared with non–TNFα-supplemented DC cultures (shaded histograms), the addition of TNFα resulted in positive cell surface expression of CD80 and an upregulated expression of CD86 costimulatory molecules (open histograms). The x-axis is a logarithmic scale of fluorescence intensity and the y-axis represents counts.