Functional characterization of BAFF transfectant. (A) Human peripheral blood B cells (1 × 10⁵ per well) were cultured with or without mitomycin-treated transfected cells (2 × 10⁴ per well) in the presence or absence of SAC (0.0002% [wt/vol]) and IL-2 (50 U/mL). After treatment for 48 hours, the expression level of CD40, ICAM-1, and HLA-DR was analyzed by FACS analysis. (B) B cells (1 × 10⁵ per well) were cocultured in triplicate in 96-well plates with mitomycin-treated transfected cells (2 × 10⁴ per well) in the presence or absence of SAC (0.0002% [wt/vol] or 0.0004% [wt/vol]) and IL-2 (50 U/mL), and [³H]thymidine (0.5 μCi [18.5 kBq] per well). Incorporation of B cells was measured during the last 18 hours of a total of 72 hours. Data are mean ± SD of triplicate wells and are representative of 3 different experiments.