Involvement of PGE₂ on the induction of FcγRIIA surface protein expression during differentiation and on phagocytosis by differentiated cells. (A) The effect of PGE₂ on induction of FcγRIIA surface expression: induction of differentiation of PLB-D by 1,25(OH)₂D₃ alone (D) or with addition of 12 μM PGE₂ every day during 4 days of differentiation (D+PGE₂). The unlabeled histogram shows the undifferentiated cells. The left plot (N) represents the negative control. The mean medians of 3 experiments are 9.5 ± 1.9, 7.6 ± 2.1, and 19.4 ± 2.2 for undifferentiated, differentiated with vitamin D (Vit D), and with Vit D with PGE₂, respectively. (B) The effect of indomethacin on FcγRIIA surface protein induction and on PGE₂ secretion during differentiation of PLB cells. Induction of differentiation by 1,25(OH)₂D₃ alone (D) or with addition of 30 μM indomethacin every day during 4 days of differentiation (D+Indo), which caused total inhibition, overlapping the undifferentiated cells (unlabeled histogram). The left plot (N) represents the negative control. In the insert the levels in the culture medium during differentiation of PLB cells in the absence (D) or presence of 30 μM indomethacin every day during 4 days of differentiation (D+Indo) are shown. (C) The effect of indomethacin on FcγRIIA surface protein induction during differentiation of HL-60 cells. Induction of differentiation by 1,25(OH)₂D₃ alone (D) or together with the addition of 30 μM indomethacin every day during 4 days of differentiation (D+Indo), which caused total inhibition, overlapping the undifferentiated cells (unlabeled histogram). The negative control (N) is shown in the left plot. (D) The effect of indomethacin on FcγRIIA expression in cultured monocytes. Indomethacin (30 μM) was added every 12 hours during 4 days of culture (Indo). Medians ± SEM of 5 independent experiments: 557 ± 87 and 410 ± 67 without and with indomethacin, respectively. Histograms in all parts of the figure are representative of 3 experiments unless otherwise indicated. (E) The kinetics of phagocytosis of OZ by PLB cells (•) and PLB-D cells (○) differentiated for 4 days by 1,25(OH)₂D₃. (F) Phagocytosis of OZ, assayed for 15 minutes, by differentiated PLB-D by 1,25(OH)₂D₃ alone or with daily addition of 12 μM PGE₂ during 4 days of differentiation. Phagocytosis by differentiated PLB cells is represented by the dotted column. (G) Phagocytosis of zymosan particles by differentiated PLB cells or PLB-D cells by 1,25(OH)₂D₃, assayed for 30 minutes. The results are the mean ± SE from 3 experiments in each assay.