Figure 4.

ZP3 expression in the murine thymic medulla is mediated by Aire. (a) ZP3 mRNA is abundant in the ovaries of both WT and Aire-deficient mice (KO) (right two bars), and is detectable in WT thymi but not KO thymi (left two bars). n=3–4 mice per condition. RQ, relative quantity with respect to a WT mouse ovary sample. (b–d) Immunohistochemical localization of ZP3 in the ovary and thymic medulla of a WT and a KO mouse. In the ovary (b; positive control), ZP3 immunoreactivity is observed surrounding the oocyte of an antral follicle (arrow) and a primary follicle. Nonspecific staining was also observed in the vicinity of vessels (*). In WT thymic medulla (c), ZP3 immunoreactivity is seen in large cells with abundant cytoplasm, presumably mTEC. Immunoreactivity was rare in thymi of Aire-deficient mice (d), although occasional positive cells were observed. Counterstain, hematoxylin. Scale bars=100 µm. AIRE, autoimmune regulator; GC, granulosa cells; ti, theca interna; te, theca externam TEC, medullary thymic epithelial cell; KO, knockout; WT, wild-type.