Fig 1: PSGL-1 could modulate immunoglobulin expression on B cells. (A) Left panel: image showing the spleens of 3-month-old WT (above) and PSGL-1-/- mice (below). Right panel: spleen weight/body weight ratio in WT (n = 40) and PSGL-1-/-mice (n = 37). Bars represent the mean+SEM. (B) Representative hematoxylin and eosin sections of the spleen of WT and PSGL-1-/-mice. (C) Percentage of splenic B cells in WT and PSGL-1-/-mice. (D) Percentage of splenic immunoglobulin expressing B cells in WT and PSGL-1-/-mice. (E) Representative density plots showing splenic immunoglobulin expressing B cells in WT and PSGL-1-/- mice: IgM+IgD+ naive B cells, IgM+ and IgD+ B cells (upper panels); IgA+ B cells (lower panels); IgG+ B cells (middle panels). (F, G) Percentage of PSGL-1 expressing cells (F) and PSGL-1 mean fluorescence intensity (MFI) (G) in different WT splenic B cell subsets expressing IgA, IgG, IgM, IgD, or IgM and IgD. In all cases, n = 10–12 mice/group. Bars represent the mean+standard deviation. *p < 0.05, **p < 0.01, ***p < 0.001 by Kruskal-Wallis test. (H) IgG2b, IgG3 and IgM serum levels in WT and PSGL-1-/- mice (n = 5 mice/group). Bars represent the mean+standard deviation. *p < 0.05 by Student’s T test.