Fig. 3.

Intracellular production of interferon (IFN)-γ and interleukin (IL)-4 by CD4⁺ T cells. Dendritic cells (DC) matured by different stimuli (5 × 10³ cells) were co-cultured with CD4⁺ T cells (2 × 10⁴ cells) and Staphylococcus aureus enterotoxin B (SEB) (100 pg/ml). After 12 days, CD4⁺ T cells were restimulated with phorbol myristate acetate (PMA) and ionomycin (last 5 h in the presence of Brefeldin A) and IFN-γ and IL-4 production per cell was measured by intracellular staining and flow cytometry. (a) One representative experiment of nine is shown. The number in the dot plots are the percentages of cells in the corresponding quadrant of the representative experiment. (b) Data represent mean percentage ± standard error of the mean of IFN-γ and IL-4 producing T cells (n = 9) after co-culture with maturation factors (MF), lipopolysaccharide (LPS) and Bifidobacterium bifidum DC. The differences observed in percentages of IL-4 and IFN-γ-positive T cells did not reach statistical significance (P > 0·05) by Mann–Whitney U-test due to large variability in the number of IL-4 positive and IFN-γ-positive T cells, but consistent effects were observed in individual experiments.