Immunohistochemical analysis of Jagged1 expression in the thymus. Frozen sections of C57BL/6 thymic lobes were stained with antibody specific for the intracellular domain of Jagged1 (green) and costained (red) with antibodies specific for medullary (TR5) or cortical epithelial cells (CDR1). Bottom panels show overlays of the 2 stains above, with the cortex (C) and medulla (M) indicated (Magnification, × 20).