Detection of Foxn1-expressing stroma cells in the thymus of WT and Foxn1 Tg mice (2-3 months) by immunofluorescent staining. Frozen sections (4-5 μm) were fixed in acetone and stained with a rabbit anti-Foxn1 antibody (IgG fraction) or purified rabbit IgG control antibody, followed by incubation with FITC-conjugated goat anti–rabbit IgG F(ab)2′. (A-B,D-E) Stained with anti-Foxn1 antibody. (C,F) Stained with purified rabbit IgG antibody. Slides were studied using Zeiss LSM 510 confocal microcopy (A,C-D,F, original magnification 25×/0.8 W; B,E, original magnification 40×/1.2 W). Insets b and e represent an enlargement of the medulla regions in panels B and E, respectively. Scale bars represent 50 μm.