IFN-α increases transcription of the TRAIL gene in neutrophils, and IFN-α-primed neutrophils contain and release elevated amounts of TRAIL/Apo-2L after BCG stimulation. (A) Human neutrophils were isolated from blood of healthy donors and placed into culture (107/mL) with BCG (1 CFU/cell), IFN-α (1000 U/mL), or left unstimulated for 20 hours. Total RNA was then isolated and TRAIL/Apo-2L mRNA levels were quantitated by real-time PCR. (B-C) Neutrophils (3 × 106/mL) were incubated with or without IFN-α (1000 U/mL) for 20 hours, and then stimulated with either IFN-α (1000 U/mL) or BCG (1 CFU/cell) for an additional 4 hours. TRAIL/Apo-2L levels were measured in the neutrophil-cell lysate (B) and culture supernatant (C) by ELISA. All groups are averages of triplicates ± standard deviation.
