FIGURE 4.

SAP inhibits phagocytosis of beads and apoptotic cells. a, SAP protein in column fractions was detected by Western blotting. Lane 1–6, fractions were eluted from Superdex 200 gel filtration. The relative inhibitory effect of each fraction on YG bead uptake by monocytes is indicated; lanes 7 and 8 are 5 and 10 μl of purified SAP (1.0 mg/ml), respectively. b, human PBMC labeled with APC-conjugated anti-CD14 mAb were resuspended in sodium medium with 0.1 mm Ca²⁺. Purified SAP was added 1 min before the addition of YG beads. The uptake of YG beads by CD14⁺ monocytes was analyzed by time-resolved flow cytometry. c, flow cytometry histograms show phagocytosis of CFSE-labeled apoptotic lymphocytes by autologous monocyte-derived macrophages labeled with CMTMR or BODIPY. Mixed cells were incubated with SAP or CytD (20 μm) for 3 h before cells were collected and fixed for flow cytometry assay.