PMN MPs enhance macrophage efferocytosis of apoptotic PMN. PMN MPs were obtained after PMN stimulation with formyl-methionyl-leucyl-phenylalanine (1μM). (A) The MP population (left panel) was monitored by flow cytometry using fluorescently conjugated AnxAV (right top panel) and anti-CD66b (right bottom panel). (B) Macrophages were prepared by differentiating peripheral blood monocytes in the presence of GM-CSF for 7 days. These were incubated with MP for 5 minutes before the addition of apoptotic (Apo) PMN. Uptake of the CFDA-labeled Apo PMN (3 × 105 cells/well) was monitored after 1-hour incubation (37°C) by assessing the levels of fluorescence (see “Phagocytosis”). (B) Results are expressed as mean ± SEM (n = 4 distinct cell preparations). *P < .05 vs macrophage plus PMN group. **P < .01 vs macrophage plus Apo PMN group.
