Bronchoalveolar cellular infiltration 3 and 24 hours after the LPS challenge in BALB/c mice. Animals were intranasally challenged with increasing concentrations of LPS (0.05 to 0.3 mg/kg) or PBS alone (50 μl). Three or 24 hours after the challenge, animals were sacrificed and bronchoalveolar lavage performed. Data are expressed as mean ± SEM from two different experiments each included 6 mice per group. Significance (P < 0.050, versus PBS challenged mice, is indicated by *. Neutro: neutrophils; Macro: macrophages; Lympho: lymphocytes; TCC: total cell counts.