Figure 2. Cxcr2 on neutrophils inhibits G-CSF and IL-17A expression in plasma and regulates neutrophil homeostasis in the BM.

(A and B) The plasma G-CSF (A) and IL-17A (B) levels in WT and Cxcr2^–/– mice (n = 4 mice/group) were measured by ELISA. (C–E) The Gr-1⁺ cell percentages (C) from the BM of the BM-reconstituted mice (n = 4 mice/group) were determined by flow cytometry, and the plasma levels of G-CSF (D) and IL-17A (E) were measured by ELISA. WW, WT BM into WT recipient mice; WK, WT BM into Cxcr2^–/– recipient mice; KW, Cxcr2^–/– BM into WT recipient mice; KK, Cxcr2^–/– BM into Cxcr2^–/– recipient mice. Isolated BM neutrophils (10⁷) from WT and Cxcr2^–/– mice were intravenously injected into Cxcr2^–/– mice (n = 3 mice/group). (F and G) After 24 hours, the plasma was prepared by coagulation-negative bleeding, and the plasma levels of G-CSF (F) and IL-17A (G) were measured by ELISA. ND, not detected. Values are means ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001.