Neutralization of G-CSF or IL-17 significantly decreases circulating neutrophil counts in CD18^−/−E^−/− mice.

(A) Peak response of neutralizing IL-17 or G-CSF function. Neutralizing IL-17 function using AdIL-17R decreased neutrophil counts in CD18^−/−E^−/− mice (n = 4) by approximately 50% on day 5, showing that IL-17 participates in regulating granulopoiesis. Anti–G-CSF antibody reduced neutrophil counts in CD18^−/−E^−/− mice (n = 3) by approximately 70% on day 1, indicating that G-CSF is the major regulator of neutrophils. *Significantly different from control group (P < .05). Data are expressed as mean ± SEM. (B) Time course of normalized neutrophil counts in individual mice treated with anti–G-CSF antibody. (C) Time course of normalized neutrophil counts in individual mice treated with AdIL-17RFc. (D) Time course of serum G-CSF levels in individual mice treated with AdIL-17RFc. Neutrophil counts and serum G-CSF levels were normalized to day 0 (100%). Different symbols represent difference mice.