Figure 1.

BLyS mRNA expression and release by activated neutrophils. (A) Purified populations of neutrophils were incubated with 1,000 U/ml G-CSF. At the time points indicated, total RNA was extracted and analyzed for BLyS, IL-1ra, and actin mRNA expression by Northern blotting. (B) Neutrophils and PBMC purified from the same donor were cultured for 21 h with or without 200 U/ml IFNγ, and then were subjected to Northern blot analysis for BLyS, CXCL-11/I-TAC, and actin mRNA expression. Data are representative of results from at least two independent experiments for each panel. (C) Neutrophils were incubated for up to 42 h at 37°C with 1,000 U/ml G-CSF and 200 U/ml IFNγ. Culture supernatants were harvested and processed for BLyS detection by a specific ELISA. Values represent means ± SEM of duplicate determinations calculated from four independent experiments. The asterisks represent significant differences between stimulated and resting neutrophils. **, P < 0.01. (D) PBMC, monocytes, and mono-DC were cultured in the presence or the absence of 200 U/ml IFNγ for 3 d. Culture supernatants were collected, and the levels of BLyS were measured by ELISA. Values represent the means of duplicate determinations calculated from two independent experiments.