Thymic mesenchymal cells are known to be important for the development of the early fetal thymus into a functionally mature organ supporting T cell differentiation. We examined the expression of mesenchymal markers: pan-mesenchymal marker ER-TR7, desmin, α-smooth muscle actin (α-SMA), and α- and β-chain of platelet-derived growth factor receptor (PDGFRα, PDGFRβ) in thymi of normal adult mice. Desmin and ER-TR7 revealed specific staining in the capsule, septa, and perivascular cells. Most perivascular cells highly expressed PDGFRβ at the same levels as desmin. Low expression of PDGFRα was detected in the capsule, intralobular septa, and some perivascular cells of normal adult thymi. α-SMA, used to identify vascular smooth muscle cells, was detectable on arterioles and some large venules but not on capillaries. Thus, desmin, PDGFRα, and PDGFRβ were localized in the capsule, septa, and perivascular cells in thymus of adult mouse, although there were differences in the expression level among these markers. On the other hand, the expression of mesenchymal markers was detectable in the region of the thymic medullary epithelium of lymphotoxin β receptor–deficient mice and plt/plt mice, indicating that mesenchymal cells were abnormally localized in the region. These results suggest that disorganization of the medullary epithelium may be accompanied by aberrant distribution of mesenchyme in adult mouse thymus. (J Histochem Cytochem 57:373–382, 2009
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.