High Bcl-2 expression protects lymphoid cells against dexamethasone or etoposide, but sensitizes to ABT-737/263. BM transitional B cells from WT and vavP–Bcl-2 transgenic mice were isolated and cultured in the presence of (A) dexamethasone, (B) etoposide, (C) ABT-737, or ABT-263 at the indicated doses for 24 hours. (D) BM transitional B cells from vavP–Mcl-1 mice are resistant to ABT-737. Survival data are shown for transitional B cells (n = 3 mice for each genotype) and are the results of 3 independent experiments, each performed in triplicate. Experiments depicted in panels C and D were performed concurrently. Values represent mean ± SEM.