Proliferation of B cells in the presence and absence of eCADO. CD19⁺ B cells were isolated from PBMC of normal donors, labeled with CFSE, and cultured in the presence of IL-4 and CD40L as described in Methods and materials. Proliferation index was determined on days 3 and 5 of culture. (A) Flow cytometry of cells from a representative proliferating B-cell culture on days 3 and 5. (B) Inhibitory CADO effects on B-cell proliferation are shown for 3 different B-cell cultures. Data are means ± standard deviation. (C) CADO at the indicated concentrations was added to B cells at the start of culture. It inhibited B-cell proliferation. Data are from a representative experiment of 3 performed with cells of different donors.