Acidification responses of WT and βc-null G-CSF–elicited peripheral blood neutrophils in response to stimulation with cytokine. The change in ECAR versus time following normalization in running buffer (DME without bicarbonate buffering, 0.1% BSA, endotoxin free) and exposure to cytokine for 6 minutes is shown. Results for mIL-3, 10² U/mL (dashed line); WT (○), βc-null#1 (□), and βc-null#2 (◊). Results for mGM-CSF (continuous line) (10² U/mL, WT [•] and 10⁴U/mL βc-null animal #1 [▪] and βc-null animal #2 [⧫]) and buffer alone (continuous line), WT (○), βc-null#1 (□). The cycle time was 2 minutes, and the pump speed was 120 μL/min with a pump-off time of 30 seconds. Three additional separate experiments were performed with similar results using a concentration of mGM-CSF in 0.1% BCS of 10² U/mL for both WT and βc-null mice with other conditions being unchanged.