Dose response of osteoclast precursors to IL-4. (A) BMMs from wild-type mice were differentiated to osteoclasts in the presence rmM-CSF (20 ng/mL), RANKL (150 ng/mL), and the indicated concentrations of IL-4 for 7 days and were stained for TRAP expression. TRAP stain; original magnification, × 10. (B) BMMs were stimulated with the indicated concentrations of IL-4 for 10 minutes and lysed. STAT6 was immunoprecipitated from each culture, blotted, and probed with an antiphosphotyrosine antibody to determine its activation state. Blots were subsequently probed with anti-STAT6 to ensure equal loading.