Figure 2.

Leukotriene C₄ (LTC₄) differentially stimulates antigen-uptake in immature and mature dendritic cells (DCs). (a,b) The DCs (1.5 × 10⁶/ml) were cultured for 30 min at 37° with or without lipopolysaccharide (LPS; 1 μg/ml), then cells were stimulated in the presence or not of 0.01 μm LTC₄ for 30 min at 37°. Then, cells were incubated with Zy-FITC (a) for 40 min at room temperature or DX-FITC (b) (100 μg/ml) for 1 hr at 37°, and antigen uptake was measured by flow cytometry. Results are expressed as mean fluorescence intensity (MFI) and represent the arithmetic mean ± SEM of six experiments. In (c), DCs or LPS-treated DCs (1.5 × 10⁶/ml) were cultured with or without LTC₄ (0.01 μm) for 30 min at 37°. Then, HRP (150 μg/ml) was added and the HRP uptake by DCs was evaluated as described in the Materials and methods. Results are expressed as optical density (OD) at 492 nm and represent the arithmetic mean ± SEM of five experiments. The results are expressed as MFI or OD and represent the arithmetic mean ± SEM of five or six experiments. Asterisk represents statistical significance (*P ≤ 0.05) versus controls and # represents significance (^#P ≤ 0.05) versus LPS.