Expression of ST6Gal-1, α2,6-sialyl ligands, and CD22 in B cells. (A) Bone marrow immature (IM), IgM-high, and mature (BMM), as well as splenic IgD-/CD21-, IgD+/CD21+, marginal zone (MZ), and follicular (FO) populations were isolated by fluorescence activated cell sorting (FACS) (>94% purity). RT-qPCR was performed for ST6Gal-1 transcripts, and representative results of three independent experiments shown relative to β2-microglobulin (n = 3). Western blot analysis of protein levels in splenic populations is quantified relative to β-actin (n = 3). (B) Mean SNA reactivity is shown for bone marrow and splenic B cell subsets (n = 5 or 10). (C) Frequency of cell surface CD22 expression in BM and splenic B cell populations (n = 5). (D) Relative RNA expression of ST6Gal-1 and SNA reactivity are compared, with standard deviations shown in both dimensions, and arrows indicating select developmental steps. (E) CD22 expression and SNA reactivity is compared, with standard deviations of measurement shown in both dimensions. Arrows indicate sequence of B cell development.