Dot-plots of FITC-labeled NF-κB decoy ODNs and F4/80 double-positive cells in BALF on day 52 in smoke-exposed mice. NF-κB decoy ODNs were capable of effective entry into alveolar macrophages in BALF. FITC-labeled NF-κB decoy ODNs were administered intratracheally on day 52 in smoke-exposed mice. As a negative control, smoke exposed mice in 52 days were treated with normal saline (F). After 3 h (A), 24 h (B), 3 days(C) and 7 days (D), macrophages (labeled F4/80) from BALF were assessed for FITC positivity using flow cytometry. A population of FITC-labeled NF-κB decoy ODNs and F4/80 double-positive cells was present in all analysis (R2, higher right quadrant) whereas R1 represented the F4/80-positive, but FITC-ODNs negative macrophages. In BALF, cells collected from mice treated with PE-conjugated isotype IgG antibody (E) as another negative control. Both of the negative controls showed false positive rate (R1+R2+R4) < 5%, which suggested the flow cytometry experiments were not interfered with nonspecific backgrounds. These results were representative of 3 comparable experiments.