Morphology, cytoplasmic immunoglobulin (cIg) expression and phenotype of B cells differentiated into in vitro plasma cells (IVPC)s. (A) Wright staining of day 0 (D0) B cells (left panel) and day 10 (D10) IVPCs (right panel). (B) cIg staining of D10 IVPCs. Left panel: D10 IVPCs expressing IgA (red), IgG (blue) and IgM (green). Right panel: D10 IVPCs expressing κ light chain (LC; green), λLC (red), and DAPI (blue). (C) SLAMF7 expression. Left panel: D0 cells and D10 IVPCs analyzed by flow cytometry for SLAMF7 expression. Isotype control (black), SLAMF7 D0 B cells (red), SLAMF7 D10 IVPCs (blue). Right panel: SLAMF7 expression by RNA-seq (p < 0.0001; D4 = day 4; n = 3 at each time point).