Induction and kinetics of CD69 expression on eosinophils cultured with IL-7. Eosinophils were preincubated for 1 h with anti-GM-CSF (20 µg/ml, triangles) or an isotype control antibody (circles) and then cultured with medium (white squares), IL-7 (50 nM, black) or GM-CSF (300 pM, gray). Expression of CD69 was determined by flow cytometric analysis of eosinophils at 0, 0.5, 1, 3, 20, and 48 h. (n = 4, *p<0.05 compared to 0 h, †p< 0.05 compared to treatment plus anti-GM-CSF). B, Effect GM-CSF neutralization on eosinophil morphology 48 h after culture with IL-7. Eosinophils were treated with IL-7 (50nM), GM-CSF (300 pM), or medium in the presence of control antibody, or neutralizing antibody to GM-CSF (20 µg/ml).