Kinetics of FcγRIIA surface protein expression and mRNA expression during differentiation of PLB and PLB-D cells by 1,25(OH)₂D₃. (A) Immunofluorescence analysis of FcγRIIA surface protein expression during the 4 days of differentiation of PLB cells by 1,25(OH)₂D₃ (histograms labeled from 0-4 days). The left plot (N) represents the negative control. The ordinate and the abscissa represent the cell number and the fluorescence intensity in a logarithmic scale, respectively. The patterns were confirmed by 3 repeated experiments. (B-C) RT-PCR analysis of FcγRIIA mRNA during 4 days of differentiation of PLB or PLB-D cells by 1,25(OH)₂D₃. The amplified products of FcγRIIA (762 bp) and (557 bp) and the corresponding products of β-actin (269 bp) are shown. The amplification of 557 bp and of 762 bp gave identical results in PLB-D cells. The intensity of each band of FcγRII mRNA was divided by the intensity of each β-actin band after quantification by densitometric scanning. Three other experiments showed similar results.