Effect of lactadherin on phagocytosis of target APL cells. A total of 1 × 106 CMFDA-labeled target APL cells were preincubated with 2nM lactadherin or annexin V for 10 minutes at room temperature, followed by removal of free protein-containing supernatant fluid. These cells were added to 5 × 105 CMTPX-stained THP-1–derived MΦs or HUVECs that were seeded in 12-well culture plates before analyses by flow cytometry. Phagocytosis was quantified by measuring the percentage of CMFDA (green)–positive red fluorescence (CMTPX) phagocytes. (A) Phagocytic index was calculated in the absence or presence of lactadherin at indicated times before 2 hours. Lactadherin enhanced the extent of phagocytosis in a time-dependent manner. Asterisk and pound sign (*, #) indicate P < .05 from phagocytosis by MΦs and ECs without lactadherin, respectively. (B) Phagocytic percentage of 2 hour-incubation was assayed after pretreatment of target APL cells with lactadherin and annexin V separately. Lactadherin enhanced phagocytosis, whereas annexin V decreased engulfment. *P < .05.
