Fig. 1.

Neutralization by mAbs against GM-CSF of bioactivity of GM-CSF. (A) Washed TF-1 cells were incubated with titrations of the indicated mAbs and 200 pg/mL rhGM-CSF. After 4 d, metabolic activity of TF-1 cells was measured by the water-soluble tetrazolium assay. (B) mAb F1 inhibits CD11b expression level on primary neutrophils stimulated by GM-CSF. Titrations of F1 mAb were added to heparinized blood with a high concentration of GM-CSF (10 ng/mL). The levels of CD11b on neutrophils were subsequently determined by flow cytometry (Fig. S3).