Human splenic cells were co-stained for flow cytometry to detect CD19, IgM, CD24, CD21, and indicated markers. CD19+IgM+ cells falling in lymphocyte light scatter were gated. A, Co-expression of CD1c and CD27 was plotted (left panel). CD1c–CD27– and CD1c+CD27+ populations were gated and their distribution with respect to CD21/CD24 subsets was plotted (right panels). B, CD19+IgM+ cells were gated into CD21/CD24 subsets (left panel). Co-expression of CD1c and CD27 in the CD21CD24 MZ (top right panel) and FM (bottom right panel) subsets is shown. C, CD19+IgM+ cells were gated into CD21/CD24 subsets and expression of IgM and IgD in the MZ and FM subsets is shown in histograms. D, CD24 and CD38 co-expression in gated CD19+IgM+CD27− cells was plotted. Gates for memory, transitional and mature B cell subsets based on the CD24/CD38 identification schema are shown (left panel). Cells in the mature subset were gated and their distribution with respect to CD21/CD24 subsets is plotted (right panels). Data shown are representative of n=4 adult human spleens.