Upregulation by bryo-1 of IL-2Rγ chain expression. (A) Total RNA was extracted from monocytes stimulated for different time points with medium alone or supplemented with increasing concentrations of bryo-1, and analyzed by Northern blot for IL-2Rγ mRNA expression (upper panel). The blot was then rehybridized with the GAPDH probe (lower panel). The two IL-2Rγ mRNA species of 1.8 and 3.6 Kb are indicated in the figure. (B) Flow cytometric analysis was performed on medium-treated monocytes or on monocytes stimulated for 12 hours with 0.001 to 0.1 ng/mL of bryo-1. Cells were stained by indirect immunofluorescence with the anti-p64 MoAb 1A11, followed by FITC-conjugated goat-antimouse IgG, as detailed in Materials and Methods. Analysis was performed on an EPICS Profile flow cytometer with gate settings specific for monocytes. Values shown indicate the MFI, determined on a logarithmic scale, of the FITCI-1A11 MoAb staining (directly related to the density of IL-2Rγ molecules in individual cells) calculated by subtracting the MFI of isotype-matching IgG1 from the MFI of 1A11-stained cells.