The differentiation of marginal-zone and germinal-center B cells is reduced in Dock8 KO mice. B cells from nonimmunized and immunized WT (n = 5) and Dock8 KO (n = 5) mice were stained with labeled Abs specific for surface markers of FO, MZ, and GC B cells. Gating strategy was as follows: FO B cells (IgM-IgD⁺), MZ B cells (CD23^lowCD21^high). Anti-mouse Abs and reagents used to stain splenic MZ B cells included allophycocyanin (APC) anti-CD21 (BioLegend), fluorescein isothiocyanate (FITC) anti-B220 (BioLegend), and phycoerythrin (PE) anti-CD23 (BD Biosciences). Anti-mouse Abs and reagents to stain splenic GC B cells included FITC-anti-CD95 (BD Biosciences), APC-anti-GL7, and PerCP-Cy5.5-anti-B220 (BD Biosciences). Anti-mouse Abs and reagents used to stain FO B cells included FITC-anti-B220, Percp-Cy5.5-anti-IgD (BioLegend), and Efluor450-anti-IgM (eBioscience) at 4°C. Then, samples were analyzed by flow cytometry. Shown are representative dot plots (A,D,G,J) and the average percentages (+SD) and numbers of cells extracted from the spleen (B-C,E-F,H-I,K-L) of 3 independent experiments. *P < .01; **P < .001.