Figure 3.

Gr1^high blood and BM monocytes shuttle between blood and BM. (A) Flow cytometry analysis of a blood monocyte graft isolated from Rag^−/− CX₃CR1^gfp mice. The GFP⁻ cells are Ly6G⁺ CX₃CR1⁻ granulocytes (reference 18). (B) Analysis of recipient BM and blood 4 d after adoptive cell transfer of Gr1^high blood monocytes (10⁵ cells). Note the presence of graft-derived (GFP⁺) Gr1^low monocytes in the blood. Fractions of graft-derived GFP⁺ cells of total CD115⁺ cells in recipient BM (0.12%) and in recipient blood (0.76%). (C) Analysis of BM and blood of WT recipients of Gr1^high BM monocytes (5 × 10⁵ cells; purity: 96%) days 1 and 3 after i.v. transfer. Note the loss of Ly6C/G expression on grafted Gr1^high BM monocytes. Bar diagrams summarize data obtained from three mice per time point. Note the difference of GFP intensity of BM and blood monocytes on day 1 (mean fluorescence intensity: 274.75 ± 13.9 vs. 376.6 ± 20.5; P = 0.003). (D) Flow cytometry analysis of BM and peritoneal cavity (PC) lavage of WT recipients of MACS-purified CD115⁺ BM monocytes (10⁶ cells; purity: 88%) that were left untreated or had been inoculated with thioglycollate. Note the recruitment of grafted Gr1^high BM monocytes to the inflamed peritoneal cavity. The data are representative of at least two independent experiments per time point.