Expression of BCMA, TACI, and BAFF-R on MM cells. (A) MM cell lines ANBL-6, DP-6, KAS-6/1, KP6, and JMW were stained with biotin-conjugated anti-TACI, anti–BAFF-R, anti-BCMA, or BLyS (gray histograms) for 30 minutes on ice, washed, and incubated with PE-streptavidin. Isotype and fluorochrome controls were done for each sample (open histograms). (B-C) CD138⁺ human MM cells (B) and CD19⁺/CD27⁺ memory B cells (C) were stained and analyzed as described for panel A..