ICAM-1 facilitates neutrophil phagocytosis in vivo. Chimeric WT mice with a mix of WT-LysM-GFP and ICAM-1 KO (GFP-negative) neutrophils were injected with LPS (1000 ng IP). After 4 hours, ZymTR was injected IP (10 µg) or IV (100 µg) 15 minutes before collection of blood, lung tissues, and peritoneal lavage. Following RBC lysis and enzymatic digestion of lung tissues, cells were labeled with DAPI and fluorescent antibodies against CD45 and Ly6G and analyzed by flow cytometry. (A) Percentage of ZymTR-associated WT-LysM-GFP or ICAM-1 KO neutrophils in peritoneal lavage. (B) Percentage of ZymTR-associated WT-LysM-GFP or ICAM-1 KO neutrophils in blood and enzymatically digested lung tissues. (C) Total number of ZymTR^pos WT-LysM-GFP or ICAM-1 KO neutrophils in the lungs of saline or LPS-stimulated animals. Values are normalized to the WT:KO ratio in the tissue of each animal. (D) Representative images showing neutrophils and ZymTR particles in LPS-stimulated pulmonary or cremasteric circulation 15 minutes after injection IV of ZymTR. Data are expressed as mean ± SEM of n = 6 to 10 animals/group. Statistically significant (t test) differences between treatment groups: *P < .05. Differences between WT-LysM-GFP and ICAM-1 KO: ##P < .01 and ###P < .001.