Expression of TGF-β and TGF-β receptor II in tonsillar lymphoid follicle. (A) Immunostain of TGF-β. There is the reticular and dotted positive stain in the apical and basal light zones but not the other follicular zones. MZ, mantle zone; LZ, light zone; DZ, dark zone. Counterstained with methyl green. Original magnification × 132. (B) Immunostain of TGF-βR II. There is the reticular expression in the apical light zone. OZ, outer zone; ALZ, apical light zone; BLZ, basal light zone; DZ, dark zone. Counterstained with methyl green. Original magnification × 100. (C) Immunocytochemical single staining (red color) of TGF-β on an isolated FDC. Original magnification × 1,280. (D) Double staining of TGF-β and R4/23 on the same FDC. There is a positive signal in the cytoplasm of FDC (brown). Counterstained with hematoxylin. Original magnification × 1,280. (E) In situ hybridization of TGF-β cDNA in the ALZ. Dendritic-shaped cells heavily labeled (arrows). Scattered lymphocytes are also stained (arrowheads). Uncounterstained. Original magnification × 860. (F) In situ hybridization of a TGF-βR II oligonucleotide in the ALZ. Many dendritic-shaped cells are strongly positive. Uncounterstained. Original magnification × 400.