Signaling through CXCR4 induces the Erk and Akt pathway in an IgD-dependent manner. (A) Western blot analysis of WT (gray), IgM−/− (blue), and IgD−/− (red) splenic B cells after stimulation with either 100 ng/mL CXCL12 or 1 µM Lat-A for 5 min compared with resting cells. (B) Western blot analysis of WT (gray), IgM−/− (blue), and IgD−/− (red) splenic B cells after stimulation with either 5 µg/mL anti-κ or 1 µM Lat-A for 1, 5, and 10 min compared with resting cells.