WASP and N-WASP are dispensable for B-cell proliferation, but regulate B-cell spreading and migration. (A) Proliferation. Splenic B cells were stimulated for 48 hours with the indicated stimulus, followed by a 16-hour pulse with [3H]thymidine to determine the proliferative response. Bars represent mean values of cpm ([3H]thymidine) ± SD of triplicate wells from 1 of at least 3 independent experiments. (B) Spreading. Spreading of activated B cells was assessed on anti-CD44 Ab-coated surfaces. White arrowhead depicts the formation of long protrusions of spread B cells. (C) Graphs showing the average of relative numbers (± SD) of spread B cells in triplicate representative of 3 experiments. (D) Migration. Splenic B or T cells were allowed to migrate to CXCL12 for 3 hours using an in vitro chemotaxis chamber. Migrating cells were collected and enumerated by flow cytometry with reference beads. The percentage of migrating cells is shown as mean values ± SD of triplicate wells and data are representative of at least 3 experiments. *P < .05 compared with WT.