Absence of Toll-like receptor 7 (TLR7) enhances neutrophil migration to the peritoneal space during polymicrobial sepsis. Twenty-four hours after surgery, peritoneal cells were harvested and analyzed using flow cytometry. Surface marker: CD45⁺ for leukocyte, CD45⁺Ly6G⁺ for neutrophil, and CD45⁺ F4/80^low for small peritoneal macrophage. (A) Total number of cells in the peritoneal cavity at 24 h after sham or cecal ligation and puncture (CLP) procedure. *P < 0.05, ** P < 0.01. (B) Representative flow cytometry plots of leukocytes (CD45⁺) population. (C) Percentage of leukocytes (CD45⁺) in the peritoneal space. (D) Leukocytes increased significantly in the TLR7^−/− septic mice as compared with that of wild-type (WT) septic mice. N = 5 to 9, * P < 0.05, ** P < 0.01. (E) Flow cytometry plots depicting the increase in neutrophil percentage in the peritoneal cavity of TLR7^−/− septic mice. (F and G) TLR7-deficiency led to marked neutrophil migration to infection site in both percentage and absolute numbers. N = 5 to 9, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. (H) Representative flow cytometry plots of small resident macrophages in the peritoneal space. (I) Percentage of small resident macrophage decreased following sepsis. N = 5 to 9 per group. *P < 0.05, ****P < 0.0001. (J) TLR7 deficiency increased the small macrophage numbers. N = 5 to 9 per group. *P < 0.05. Unequal variance t test. Data are expressed as mean ± SD.