Expression of TNFR I in tonsillar lymphoid follicle. (A and B) Immunostains of TNFR I. A lacy positive pattern (A) is evident in the apical and basal light zones. High-power view of the basal light zone, showing a heavily labeled lacy pattern (B). MZ, mantle zone; LZ, light zone; DZ, dark zone. (A) Original magnification × 98, (B) Original magnification × 300. (C and D) Immunoelectron micrographs of TNFR I in the tonsillar light zone. The cell surface of a binucleated FDC and the surface of the labyrinth-like structure of FDC embracing lymphocyte (L) are positively stained. Bar = 1 nm. (C) Original magnification × 5,700, (D) Original magnification × 10,080.