Fig. 2

Histology, thymic epithelial organization and FOXN1 protein expression. Photomicrographs show morphological aspects of thymus samples from (a) five days (“Postnatal” group) and (b) 57 years-old donors (“Adult” group). Paraffin sections were stained with haematoxilin-eosin stain and analyzed by light microscopic examination. (4x, objective magnification). c = cortical region; m = medullary region; a = Adipose tissue; arrow = connective tissue septum. Panels (c) and (d) show cytokeratin staining of “Postnatal” (5 days-old) and “Adult” thymic samples (57 years-old), respectively. Frozen thymus sections were reacted with specific pan anti-cytokeratin polyclonal rabbit antibody followed by Alexa-488 conjugated anti-rabbit Ig antibody (green) before visualization in the fluorescent microscope. (20x, objective magnification). Photomicrographs (e) and (f) show FOXN1 protein expression in thymus cryosections from “Postnatal” (5 days-old) and “Adult” donors (57 years-old), respectively. In order to demonstrate thymic epithelium associated FOXN1 expression, the sections were first reacted with anti-human FOXN1 antibody (red) and subsequently double stained with pan anti-cytokeratin antibody (green). (20x, objective magnification)