IκBα worsened ALI induced by prolonged pneumonia. Overexpression of IκBα did not alter the decrement in arterial oxygenation (A). IκBα worsened the Escherichia coli-induced decrement in static lung compliance, with effect greatest with 5 × 1010 IκBα particles (B). IκBα did not alter BAL protein concentrations (C), but did significantly increase the percentage of neutrophils in the alveolar infiltrate (D). The gray bars represent sham (uninfected) animals. Vehicle, animals that received intratracheal vehicle alone; IκBα 5 × 109, animals that received 5 × 109 AAV6 particles encoding IκBα; IκBα 1 × 1010, animals that received 1 × 1010 AAV6 particles encoding IκBα; IκBα 5 × 1010, animals that received 5 × 1010 AAV6 particles encoding IκBα. Significantly different from vehicle group (P < 0.05, ANOVA).