Human neutrophils express IL-17RA but not IL-17RC. Freshly isolated neutrophils (PMN), monocytes (Mono), and HBECs were evaluated for IL-17RA and IL-17RC surface (A) and mRNA (B) expression by flow cytometry (empty histogram: isotype control Abs; filled histogram: specific Abs) and real-time RT-PCR, respectively. (C-D) Act1 mRNA expression was evaluated in freshly isolated neutrophils, monocytes, and HBECs (C) as well as in neutrophils incubated for 21 hours with IFN-γ and/or LPS (D). (E) Act1 protein expression was evaluated by Western blot analysis of whole-cell extracts prepared from HBECs and freshly prepared monocytes (T₀), as well as of cytoplasmic cavitates prepared from neutrophils, freshly isolated (T₀) or incubated for 21 hours with IFN-γ and/or LPS (T_{21 h}). One representative of at least 3 independent experiments with similar results is shown in each panel.