In vitro effects of FTY720 on B-cell proliferation and antibody production. Purified splenic B cells were stimulated with anti-CD40 monoclonal antibody in the absence or presence of various concentrations of FTY720. Cellular proliferation (A) and IgG production (B) were measured after 3 days of culture. Data (mean ± SE) were from triplicate samples. Similar results were obtained in 2 independent experiments.