In cultured human tracheal epithelial cells, tulobuterol (1.0 μmol/L, 72 h) produced a small but significant reduction of the amount of p50, p65, and c-Rel of NF-κB in the nuclear extracts compared with the levels observed in the cells treated with vehicle (Fig. 6A–C) and observed in the cells prior to RV14 infection (data not shown). Here, REL is linked to infection.