Phagocytic potential of aged neutrophils. The phagocytic potential of aged and nonaged neutrophils for E coli bioparticles was analyzed as detailed in “Methods.” (A) Representative confocal microscopy images illustrating phagocytosis of E coli bioparticles by unstimulated and LPS-stimulated neutrophils (bars represent 5 µm). Quantitative data for aged and nonaged neutrophils isolated from the peripheral blood of unstimulated WT mice upon exposure to PBS or varying concentrations of LPS, as well as to the CXCR4 inhibitor AMD3100, the TLR-4 inhibitor TAK-242, blocking anti-Mac-1/CD11b mAbs, the spleen tyrosine kinase inhibitor BAY 61-3606, or drug vehicle/isotype control (mean ± SEM for n = 4; ^#P < .05 vs nonaged; *P < .05 vs PBS; ^§P < .05 vs drug vehicle/isotype control). (B) Quantitative data for aged and nonaged neutrophils isolated from the blood or from lysates of different organs of WT mice undergoing intra-arterial injection of E coli bioparticles and IP injection of LPS (mean ± SEM for n = 5; ^#P < .05 vs nonaged neutrophils).