Mac-1 deficiency inhibits the loss of leukocytes from the peritoneum. (A) The TG-conditioned WT and Mac-1^-/- mice were injected intraperitoneally with either PBS or LPS. Four hours later, the total leukocytes in peritoneum were determined. The data represent the mean ± SD (n = 6) and are representative of 3 independent experiments. (B) WT or Mac-1^-/- peritoneal macrophages were stimulated with different concentrations of LPS. Four hours later, the amount of TNFα produced was determined by ELISA. The data shown are representative of 2 independent experiments. (C-D) The GFP⁺ peritoneal macrophages were injected intraperitoneally into TG-preconditioned WT mice, followed with intraperitoneal injections of PBS or LPS. At different time points, the peritoneal membrane was washed, fixed, and photographed using a fluorescence microscope (objective × 100) (C), and the percentage of GFP⁺ cells in total peritoneal cells was analyzed by FACS (D). The number of adherent GFP⁺ cells on the peritoneal mesothelium was counted manually based on 4 randomly picked fields. The data represent the mean ± SD of 3 mice and are representative of 3 independent experiments. ^*PBS versus LPS, P < .001.