Involvement of PKA in induction of FcγRII expression during differentiation. (A) EP4 mRNA: representative RT-PCR analysis of EP4 mRNA during 4 days of differentiation of PLB cells or PLB-D cells by 1,25(OH)₂D₃. Amplification of β-actin was done as a control. Three other experiments showed similar results. (B) The effect of PKA inhibitor on FcγRIIA expression detected by immunofluorescent analysis induced by 1,25(OH)₂D₃. Induction of differentiation of PLB cells by 1,25(OH)₂D₃ alone (D) or with addition of 10 μM H-89 (D+H89) every day during 4 days of differentiation. Undifferentiated cells are shown by the unlabeled plot overlapping with D+H89 treatment. (C-D) Induction of FcγRIIA expression by dbcAMP. Immunofluorescent analysis of FcγRIIA expression in PLB cells (histogram C) and PLB-D cells (histogram D) at 1 day of differentiation by 0.3 mM dbcAMP. (E) The effect of PKA inhibitor on FcγRII expression induced by dbcAMP. Induction of differentiation of PLB cells by dbcAMP alone or with addition of 10 μM H-89 (dbcAMP+H89) every day during 4 days of differentiation. (F) Kinetics of FcγRII protein expression (detected by immunofluorescent analysis) and of RT-PCR FcγRIIA mRNA (insert) induced by dbcAMP in PLB cells. (G) Immunofluorescent analysis of CR3 protein expression at 1 day and 3 days of differentiation induced by dbcAMP in PLB cells. In all experiments, results are representative of 3 experiments. The left plots are the negative controls (N) and unlabeled plots represent undifferentiated cells.