Fibrinogen interacts with CD11b⁺ cells but there are redundant ET-releasing cell types. (A) Mice deficient for gp91/phox were injected with Alhydrogel and evaluated for fibrin ET formation 5 hours later. (B) Mice were depleted of neutrophils with 200 μg of anti–Gr-1 intravenously at day −1, or injected with isotype control Ab, then tested for fibrin ET formation 5 hours after Alhydrogel injection. (C) Peritoneal lavage was collected from mice in Figure 4B. Cells were stained by Wright-Giemsa and neutrophils and eosinophils were counted. *P < .001 compared with Rat IgG. (D) Kit^W/Wv mice, or littermate controls, were injected with Alhydrogel and evaluated for fibrin ET formation 5 hours later. Note that fibrin ET formation was decreased by 35% (P = .03). (E) Kit^W/Wv mice, or littermate controls, were depleted of neutrophils with 200 μg of anti–Gr-1 intravenously at day −1 or given isotype control Ab. On day 0, mice were injected with Alhydrogel and evaluated for fibrin ET formation 5 hours later. (F) Nodules from the peritoneal lavage of mice in part E were stained by Wright-Giemsa. Top left, Kit^+/+ mice receiving Rat IgG. Top right, Kit^+/+ mice receiving anti–Gr-1. Bottom right, Kit^W/Wv mice receiving anti–Gr-1. N indicates neutrophil; E, eosinophil; M, mononuclear cell. (G) FibG 390-396A mice were injected with Alhydrogel and evaluated for nodule formation 5 hours later. (H) Nodules from FibG 390-396A mice or controls were counted and the average weight determined (*P = .02). All experiments included at least 3 mice per group and were performed at least 3 times, except panel E, which was performed twice with 4 mice per group and shows the average from all 8 mice.