CXCR7 blockers affect CXCL12 availability and neutrophil mobilization. (A) Increased expression of CXCR7 on the cell surface of MZ but not FO B cells in mice treated with CCX754 for 2 days. Data are representative of ≥ 3 similar experiments. (B) Increased serum levels of CXCL12 in mice treated with CCX754 for 2 days. Data are pooled from 3 independent experiments. Each symbol represents a mouse. (C) Frequencies of neutrophils in the spleen of indicated groups were analyzed by flow cytometry. Neutrophils were gated as CD19⁻Gr-1^briCD11b⁺. Each dot represents a mouse. Data are representative of ≥ 3 separate experiments with similar results. Horizontal bars represent the median values (B and C).