Fig. 4.

IT instillation of IL-1β+TNF-α resulted in an increase in bronchoalveolar lavage fluid (BALF) cell concentration (A) compared with placebo-treated mice at 6 h (P = 0.011). By 24 h the cell count had declined but was still greater than that in placebo-treated mice (P = 0.002). Data are means (±SE) of 4 animals/group. B and C: representative fluorescence-activated cell sorting (FACS) data showing the distribution (%) of leukocytes in BALF acquired from a single animal 6 h after IL-1β+TNF-α treatment (B) or placebo treatment (C). The mean (±SE) distribution of BALF neutrophils from all lavaged IL-1β+TNF-α-treated mice was 76.8 ± 2.2% compared with 1.6 ± 0.9% for all lavaged placebo-treated mice (P < 0.0001). Macrophages were less prevalent in IL-1β+TNF-α-treated mice than in placebo-treated mice (89.1 ± 2.0% vs. 0.6 ± 0.4%, P < 0.0001). This shift in the differential reflects the acute nature of the inflammation and is further evidenced by the presence of more aggregates, which most likely represent neutrophil-macrophage interactions, in the IL-1β+TNF-α-treated mice.