CD1c as a strong marker of splenic marginal zone B cells in humans. Serial cryosections of an adult human spleen are stained with anti-CD20, anti-IgD, anti-CD1c, and anti-CD27 antibodies (ABC technique; original magnification, × 25) marginal zone B cells are IgD^lowCD27⁺CD1c^high. Note the more intense staining for IgD of the corona (Co) compared with the MZ B cells while the reverse is true for CD1c. The intense IgD staining of outer marginal zone B cells has been described previously.¹⁶  GC indicates germinal center.