Mast cell transfer experiments confirm a requirement for α2β1 integrin on PMCs during the inflammatory response to Listeria. (A,B) Representative flow cytometric profiles of uninfected mast cell–deficient WBB6F1-W/W^v mice reconstituted with wild-type (A) or α2 integrin–deficient (B) PMCs. Reconstituted, uninfected mice contained equivalent numbers of total peritoneal cells (5.6 × 10⁶ [0.21%] for WT reconstituted mice and 5.2 × 10⁶ [0.26%] for KO reconstituted mice) and equivalent percentages of PMCs (approximately 0.2%). (C,D) Mast cell–deficient mice reconstituted with either wild-type (WT) or α2 integrin–deficient (KO) mast cells were infected with 5 × 10⁴Listeria intraperitoneally. At 6 hours after infection, the percentage of PMN and the absolute PMN number were determined. The average total peritoneal cell number in reconstituted, infected mice was as follows: 8.1 × 10⁶ in WT reconstituted mice and 5.6 × 10⁶ in KO reconstituted mice. Shown is a combination of 2 experiments. Uninfected groups each contained 2 mice. Infected groups contained 4-5 mice. Results are presented as means ± SEM.