Age-related structural changes in spleen of lpr mice. (A) Spleen sections of the indicated mice (upper row), HES staining (middle row), and immunohistochemical analysis with anti-PAX5 antibody (lower row). Fo: B-cell follicles. The location of the marginal sinus is indicated by the dashed black line. (B) Spleen sections from the indicated mice stained with DAPI (blue), anti-MAdCAM-1 (green), and anti-CD3 antibody (red). The MAdCAM-1(⁺) cells delineate the marginal sinus and reveal age-dependent extension of this meshwork, which is filled with CD3⁺ cells in homozygous lpr^cg mice. (C) Spleen sections from the indicated mice stained with DAPI (blue), anti-CD1d (green), and anti-CD3 antibody (red). CD1d identifies MZ B cells.