CD74 downstream signaling cascade elevates the proportion of mature B cells. (A-D) Splenocytes from control mice were stimulated with anti-CD74 antibody or anti-CD8 antibody in the absence (A-B) or presence (C-D) of the PI3K inhibitors wortmannin (Wo) or LY 294002 (LY), or the Syk inhibitor, piceatannol (Pico) for 24 hours. (A,C) Cells were triple stained with anti-B220, anti-IgD, and anti-IgM antibodies. Dot plots show the IgD and IgM populations on B220⁺ cells. (B,D) Graphic presentation of the total mature B-cell number from the experiment in panels A (shown in B) or C (shown in D). The results shown represent the average of at least 4 independent experiments with similar results. Error bars represent the standard deviation of the results in the 4 experiments included.