HS10 and Ed but not E3′ are required for maximal Igκ expression in plasma cells. A, FACS analysis of splenic plasma cell levels (B220low and negative CD138high, boxed or circled regions) from WT, HS10−/−, E3′−/− and Ed−/− mice, before (upper panels) and 5 days after immunization with sheep red blood cells (SRBC) (lower panels). Data are representative of independent FACS analyses from at least 6 mice of each genotype. B, FACS analysis of Igκ expression in permeabilized splenic plasma cells from WT, HS10−/−, E3′−/− and Ed−/− mice, before (upper panels) and 5 days after immunization with SCBC (lower panels). Data are representative of independent FACS analyses from at least 6 mice of each genotype. C, Realtime PCR assays of Igκ transcript levels in FACS sorted splenic plasma cells from WT, HS10−/−, E3′−/− and Ed−/− mice before and 5 days after SRBC immunization. Double asterisks indicate p< 0.01.