NF-κB activity is affected in the absence of Vav proteins. (A) c-Rel abundance in nuclear extracts from wild-type (□) or Vav-deficient (▪) B cells. Results are expressed relative to the levels found in wild-type cells and correspond to the mean ± SD of B cells from 3 independent mice. (B) mRNA levels of NF-κB subunits from sorted wild-type (□) and Vav-deficient (▪) mature B cells were compared by real-time PCR. CXCR5 expression was included as control because it is expressed at similar levels in wild-type and Vav-deficient cells (Figure 4B). (C) Purified splenic B cells from wild-type or Vav-deficient cells were blotted with antibodies against c-Rel, Rel-A, or tubulin (loading control). (D) Spleen cells were stained with antibodies against c-Rel, CD93, IgM, and CD23, and subsets are defined as indicated in Figure 1A-B. In the histogram overlays, the solid line represents Vav-deficient cells, the broken line represents wild-type cells, and the shaded histograms correspond to the isotype control. Data are representative of 5 mice from each group.