Fig. 6

Belimumab differs from atacicept in that it does not inhibit BAFF 60-mer promptly. BAFF-responsive BAFFR:Fas reporter cells were treated overnight with titrated amounts of the indicated forms of BAFF, in the presence or absence of the inhibitors atacicept or belimumab at fixed concentrations. Cell viability was then monitored. a, b Inhibition of Fc-BAFF by atacicept (a) or belimumab (b). The experiment was performed 3 times. c, d Naturally processed hBAFF in supernatants of transfected 293 T cells exposed to atacicept at 0 or 5 ng/ml (c) or belimumab at 80  ng/ml (d). The experiment was performed twice. e, f Inhibition of Fc-BAFF by atacicept (e) or belimumab (f). The experiment was performed 3 times. g BAFF 60-mer was titrated in medium, then incubated in medium for 3 days at 37 °C, then added to reporter cells. Alternatively, BAFF 60-mer was titrated in medium just before the assay (fresh). h, i BAFF 60-mer was titrated in medium without or with atacicept (h) or belimumab (i) for 3 days at 37 °C. Samples without inhibitors received inhibitor or not after 3 days of incubation. Samples were then added to reporter cells. The experiment was performed twice. Panels a, b, e, and f show the mean ± SEM of 5 replicates, panels c and d of duplicate, and panels g, h and i of triplicate measures. The condition without inhibitor is the same in panels a and b, in panels c and d, in panels e and f, and in panels g, h, and i. See also Supplementary Fig. 5