Vav-deficient B cells show defects in expression of activation markers following anti-CD180 and LPS stimulation. Purified splenic B cells from WT or Vav1/2^-/- mice were cultured for 26 hours and analyzed for the expression of (A) activation markers CD86 and CD25 or (B) intracellular levels of Bcl-xL. □ indicates media-only-cultured cells; ▪, CD180-stimulated cells; and ▦, LPS-stimulated cells. Error bars represent standard deviation (n = 3). Difference in increase: ^*P < .05; ^**P < .01; ^***P < .001 by Student t test. MFI indicates mean fluorescence intensity.