Although surface levels of L-selectin are elevated on Adam17^−/− monocytes relative to WT controls, their recruitment to the peritoneal cavity is not accelerated and L-selectin levels do not change on emigration into the peritoneal cavity. As described in the legend to Figure 1, the sterile peritonitis model was used to study monocytic cell recruitment to the peritoneal cavity. (A) Peritoneal cells were collected at the indicated time points after thioglycollate injection (n = 4-5 per group), as well as resident peritoneal cells without stimulation (t = 0). Individual cell numbers were determined and flow cytometry was performed using antibody staining to identify monocytic cells as F4/80⁺. (B) Cell-surface levels of L-selectin were evaluated on circulating and peritoneal monocytic cells by flow cytometry using antibody staining for CD11b⁺ and Ly6G⁻ cells. Data are expressed as means ± SD of mean fluorescent intensity (n = 4-5 per group). Statistical significance is indicated (*P < .01 and **P < .02), and these representative data were confirmed in at least 3 replicate experiments. (C) Mixed chimeras were generated containing 50% each WT (Ly5.1) and Adam17-null (Ly5.2) bone marrow. The relative contribution of Adam17^+/+ and Adam17^−/− monocytes to total circulating monocytes (unstimulated, t = 0, n = 4) and peritoneal macrophages (16 hours after thioglycollate injection, n = 4) were evaluated. Mixed chimeras were evaluated in one other experiment at 24 hours after thioglycollate administration, with similar effects observed. All data are expressed as means ± SD.