IFN-γ expression by naive T cells after activation with mature DCs in an HIGM3 patient. (A) Intracellular expression of IFN-γ by cord blood-derived T cells after activation with mature DCs in a healthy subject and HIGM3 patient 1. Monocyte-derived and CD154 trimer (black bars) or LPS + IFN-γ-matured (gray bars) DCs (medium only [white bars] is the internal negative control) (1 × 10⁵/well) were cultured with 1 × 10⁶ cord blood-derived allogeneic T cells, as described in “Patients, materials, and methods.” Intracellular IFN-γ production was evaluated by intracellular staining after cellular permeabilization. The number of cells expressing IFN-γ is shown on the y-axis as the percentage of cells. Significant difference in the patient compared with control subject as assessed by statistical analysis (P < .05). (B) IFN-γ production by alloreactive naive T cells induced to proliferate by TNF-α, LPS, or LPS + IFN-γ-matured DCs. Naive T lymphocytes (1.5 × 10⁵/well) were purified by negative selection from healthy donor PBMCs and cultured with soluble TNF-α (white bars), LPS (black bars), or LPS + IFN-γ-matured (gray bars) DCs (5 × 10³ cells) from controls (adult and child) and HIGM3 patient 1 in the presence of 1 ng/mL SEB (see “Patients, materials, and methods”). The supernatant was collected after 5 days at 37°C, and the production of IFN-γ was measured using ELISA. Cells used for this experiment correspond to those of the MLR assay described in Figure 4B. Data are expressed in pg/mL (mean ± SD of an experiment performed in triplicate). Adult and child data are from control subjects. ^*Significant difference in the patient in comparison with control subjects as assessed by statistical analysis (P < .05). Results shown are representative of 2 independent experiments.