NFKB1 and infection: 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).