Quantification of lung edema. Water-to-wet weight ratios of the lungs were measured at 4-h time points in the rats infected with P. aeruginosa. as an index of acute lung edema. In the control group (Control, no bacteria), only lactated Ringer's solution was instilled into the airspace of the rats and no therapeutic intervention was taken. Three sets of rats were co-instilled P. aeruginosa PA103 with 4 mg/kg of either irrelevant monoclonal IgG (Control IgG), rabbit polyclonal anti-PcrV IgG (Rab anti-PcrV), or murine monoclonal anti-PcrV IgG (Mab166). Four sets of rats were intratracheally administered either phosphate-buffered saline (PBS), rabbit polyclonal anti-PcrV IgG (Rab anti-PcrV)(4 mg/kg), murine monoclonal anti-PcrV IgG (Mab166)(4 mg/kg), or Mab166 Fab (4 mg/kg). Data are shown as means+standard errors. The numbers of animals are listed in Table 1. +P < 0.05 to the control group (no bacteria) and *P < 0.05 to the control IgG group in co-instillation and to the group without IgG (PBS) in therapeutic administration by two way-ANOVA, followed by the Newman-Keuls t-test.