Figure 7. SMAC mimetic compounds mimic co-stimulatory properties of BAFF in B lymphocyte activation.

(a) WT and Traf3^−/− MEFs were cultured in media alone or a 5-fold dilution series (high dose 500 nM) of SM for 12 hr. Activation of the noncanonical NF-κB pathway was then assessed by immunoblot analysis of p100 to p52 processing. (b) WT and Map3k14^−/− 3T3s were cultured in media alone, in the presence of 2 µg/ml agonistic αLTβR antibody, or 50 nM SM for 12 hr. Activation of the noncanonical NF-κB pathway was then assessed by immunoblot analysis of p100 to p52 processing. (c) Primary B-lymphocytes were cultured in media alone, in the presence of a 5-fold dilution series (high dose 500 nM) of SM, 100 ng/ml of BAFF, or 5 µg/ml of anti-CD40 for 12 hr. Activation of the noncanonical NF-κB pathway was then assessed by immunoblot analysis of p100 to p52 processing. (d) Primary B-lymphocytes were cultured in media alone or in the presence of 3 fold titrations of BAFF, SM, or LBW242 (high dose 300 ng/ml, 300 nM, 300 nM respectively) for 72 hr. Cell viability was then determined by propidium iodide exclusion assay and analyzed by FACS. Stimulations were performed in triplicate. (e) Primary B-lymphocytes were cultured in the presence of the indicated titrations of CpG alone, or in the presence of the indicated concentrations of BAFF or LBW242 for 72 hr. Cellular Proliferation was then assessed by measurement of incorporated [H³]-Thymidine. Stimulations were performed in triplicate with bars indicating ± s.e.m. *, P < 0.05, **, P < 0.01. Data are representative of at least three independent experiments.