Reduced macrophage proliferation from Nbs1^∆B/∆B mice in a model of sterile inflammation. Control and Nbs1^∆B/∆B mice were injected in the peritoneal cavity with 2 × 10⁶ zymosan particles or PBS (control). (A) Gating strategy of peritoneal cells after staining with anti-CD11b, anti-F4/80, and anti-Ki67 (cell marker for proliferation). FS-W, forward scatter–width; FSS, forward scatter signal; SS-A, side scatter–area. (B) The percentage of Ki-67⁺F4/80⁺ cells (macrophages) and Ki-67⁺F4/80^– cells was determined for animals treated with either PBS or zymosan. For the control experiments, 7 control mice and 6 Nbs1^∆B mice were used, and for the experiment with zymosan, 8 control mice and 7 Nbs1^∆B/∆B mice were used. ***P < .001. (C) Proliferation of peritoneal macrophages. Macrophages were obtained by peritoneal lavage and purified by adhesion. Proliferation was determined by thymidine incorporation after 24 hours of incubation with M-CSF (n = 4). cpm, counts per minute. The results are shown as mean ± SD. *P < .01 in relation to the corresponding controls.