Neutrophils stimulated with BCG, but not IFN, release TRAIL /Apo-2L. (A-B) Human neutrophils were isolated from blood of healthy donors and placed into culture (3 × 106/mL) with BCG (1 CFU/cell), IFN-α (100 or 1000 U/mL), or both for 4 hours. Cells were then examined for surface TRAIL/Apo-2L expression by flow cytometry (A) or the culture supernatant was assayed for TRAIL/Apo-2L levels by ELISA (B). Filled histograms represent staining with isotype mAb; unfilled histograms, staining with anti-TRAIL mAb. (C) Neutrophils (3 × 106/mL) were stimulated in vitro with BCG (1 CFU/cell), IFN-α (100 U/mL), or IFN-γ (100 U/mL), and TRAIL/Apo-2L levels were measured in the culture supernatant over a 24-hour period. (D) Expression of CD62L on unstimulated and BCG-stimulated neutrophils as measured by flow cytometry. (E) IL-8 production by unstimulated, BCG-simulated (1 CFU/cell), or LPS-stimulated (100 ng/mL) neutrophils (3 × 106/mL) was measured by ELISA after 24 hours. Results in panels A, C, and D are representative of at least 3 independent experiments, whereas the results in B and E are averaged from 3 separate experiments.
