Figure 2

Elevated levels of HMGB1 in BAL of CF patients inhibit bacterial clearance. The levels of HMGB1 in BAL of either CF patients or normal healthy volunteers (A) and of either CFTR^-/- mice (CFTR-KO) or WT mice (B) were determined by immunoblotting analysis and quantified. Representative immunoblots are shown (A) and (B). (C) The phagocytic activity of RAW 264.7 macrophages was determined using heat-killed PAO1 in the presence of BAL from either CF patients (CF) or normal healthy volunteers (normal). Some CF BAL was pretreated with either anti-HMGB1 polyclonal antibodies (CF/αHMGB1) or control antibodies (CF/control). Macrophages were stained with phalloidin, and internalized PAO1 was counted and analyzed. (D). CFTR^-/- mice were treated with either anti-HMGB1 mAbs (αHMGB1) or isotype control antibody as described in Figure 1. Viable bacteria in the lung were quantified by plating serial dilutions of homogenized lungs and expressed as CFUs/lung (n = 5–6 mice per group of three independent experiments). Mean ± SEM. * and #, P < 0.05 compared with either normal healthy volunteers (A and C) or WT mice (B) or subjects treated with isotype control antibodies (C and D), respectively.