FIGURE 7.

Early KGF induced bacterial clearance is GM-CSF dependent. Panel A, E. coli (2 × 10⁷ colony forming units) were inoculated into wild type C57BL/6 mice 1 h after a single dose of intranasal KGF (5 mg/kg). Lungs were harvested after 6 h for homogenization, plating, and colony counting. Results are mean ± S.E. of five mice in each group. Panel B, mice were pretreated intraperitoneal (100 μg/mouse) with either anti-GM-CSF mAb 22E9 or IgG2a isotype control 24 h prior to KGF treatment. GM-CSF levels in the lung homogenate were measured by ELISA. Data are mean ± S.E.; n = 4. Panel C, C57BL/6 mice were pretreated intraperitoneal (100 μg/mouse) with either anti-GM-CSF mAb 22E9 or IgG2 isotype control antibody 24 h prior to intranasal KGF administration. One hour later, the mice were challenged intranasally with 2 × 10⁷ colony forming units of E. coli. After 6 h, lungs were harvested, homogenized, and plated for bacterial colony counting. Results are mean ± S.E., n = 5 mice in each group.