Glce^−/− BM plasma show impaired APRIL-mediated survival. (A) APRIL-mediated survival of Glce^+/+ and Glce^−/− BM plasma cells. BM was isolated from Glce^+/+ and Glce^−/− mice and cultured in vitro with or without APRIL (200 ng/mL). Bars represent the relative number of surviving plasma cells (B220⁻, Syndecan-1⁺, and Ly6c⁺) after 10 days of culture of 3 independent experiments (mean ± SEM). *P < .05. (B) Unlike APRIL-mediated survival, BAFF-mediated BM plasma cell survival is independent of Glce activity. Glce^+/+ and Glce^−/− BM plasma cells were isolated and cultured as described earlier in the Figure 7 legend. Bar diagram represents the relative number of surviving BM plasma cells at day 10 (mean ± SEM). *P < .05. BAFF (200 ng/mL); TACI-Ig (2 μg/mL); APRIL* (200 ng/mL) = APRIL mutant that cannot bind to HS.