Prior activation of the heat-shock response by whole-body hyperthermia decreases lung bacterial clearance and increases lung epithelial protein permeability in a mouse model of Pseudomonas aeruginosa pneumonia. (A and B) C57BL/6 mice were left untreated or underwent a heat-shock response with whole-body hyperthermia that was followed 24 h later by airspace instillation of P. aeruginosa (PAK strain, 1 × 10⁷ colony-forming units [CFU]) or its vehicle. Mice were euthanized 4 h later and either bacteria were counted in the lung homogenates or protein concentration was measured in the bronchial alveolar lavage (BAL) fluid. For all experiments, results are shown as mean ± SD (n = 6 mice per group); *P ≤ 0.05 from controls; **P ≤ 0.05 from mice with PAK alone.