Fig. 1

IL-4⁺-DC have reduced capacity to induce proliferation and activation of allogeneic CD4⁺ T cells. a In the MLR assay, allogeneic CD4⁺ T cells (1 × 10⁵/100 µL) were co-cultured with increasing numbers of IL-4⁻ or IL-4⁺-DC (1 × 10⁴, 3 × 10⁴ or 1 × 10⁵/10 µL) for 5 days. Dendritic cells alone (1 × 10⁵/100 µL) were used as a control. Proliferation was measured by the addition of ³H thymidine 18 h before the end of the co-culture and radioactivity was quantified on a β counter. The results are representative of three independent experiments. b Allogeneic CD4⁺ T cells (1 × 10⁵/100 µL), co-cultured with IL-4⁻ or IL-4⁺-DC (3 × 10⁴/100 µL) for 5 days, were removed, stained with specific mAb for CD69 and CD25, or their isotype controls, and analyzed by flow cytometry. Labeled cells were gated on CD3⁺/DC-SIGN⁻ cells. c The results are expressed as the mean ± SEM  % of CD4⁺ T cells expressing the indicated markers of six independent experiments. *P < 0.05, compared to IL-4⁻-DC/CD4⁺. d IL-4⁻ and IL-4⁺-DC (3 × 10⁴/100 µL) were co-cultured with allogeneic CD4⁺ T cells (1 × 10⁵/100 µL) for 5 days and the supernatants were analyzed for IL-2, IFN-γ, and IL-5, using ELISA. The results are the mean ± SEM of six to eight separate experiments. *P < 0.05, compared to IL-4⁻-DC/CD4⁺. e Flow cytometry analysis of intracellular IFN-γ content. CD4⁺ T cells were fixed, permeabilized and stained with APC-anti-IFN-γ mAb (bold lines) or its isotype control (thin lines). The histograms are representative of five experiments. f MFI of IFN-γ labeling calculated from the total fraction of CD4⁺ T cells at days 5 and 6 of co-culture. The results are the mean ± SEM of the MFI of labeled cells from four to five separate experiments. *P < 0.05, compared to IL-4⁻-DC/CD4⁺