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. 2001 Aug;159(2):501–512. doi: 10.1016/S0002-9440(10)61722-1

Figure 2.

Figure 2.

A: CD4-positive T lymphocytes in a secondary follicle. Top: A longitudinal and partially tangential section of the PALS. Many CD4-positive T cells are present in the germinal center, whereas only few CD4-positive T cells occur in the mantle zone and in the inner MZ. A prominent ring-like accumulation of CD4-positive T cells occurs at the border between inner MZ and outer MZ. ABC technique on autoclaved paraffin section using mAb 1F6. Final magnification, ×69. B: Double staining for smooth muscle α-actin (dark blue) and CD3 (brown) in a degenerating secondary follicle. Inset shows a 1.4-fold magnification of the top right part of the figure. CD3-positive T cells are closely associated with the most strongly smooth muscle α-actin-positive branched cells in the MZ. The PALS is situated on the right and left side of the follicle. mAb asm-1 is highly diluted to permit better visualization of the apposed CD3-positive cells. APAAP technique with nitro blue tetrazolium/BCIP for mAb asm-1 and ABC with DAB for CD3 antiserum. Final magnification, ×110. C: CD8-positive cells in the same secondary follicle as shown in A. CD8-positive cells do not accumulate in the follicle. Many small round cells and sinus endothelia are stained in the red pulp. ABC technique on autoclaved paraffin section using mAb 4B11. Final magnification, ×69. D: Erythrocytes in the perifollicular zone demonstrated by DAB. A similar pattern is revealed by staining for CD14 or CD15. Final magnification, ×28. E: Strongly sialoadhesin-positive macrophages (blue) scattered in the perifollicular zone. The brown background staining is because of residual peroxidatic activity of erythrocytes outlining the perifollicular zone. Cryosection without nuclear counterstain. mAb HSN-1 revealed by an APAAP technique with fast blue, erythrocytes are stained by DAB. Final magnification, ×110. F: MAdCAM-1-positive cells in a secondary follicle and PALS. Rows of strongly MAdCAM-1-positive branched cells occur at the border of the inner and outer MZ. More weakly staining cells are located in the outer MZ and perifollicular zone. MAdCAM-1-positive cells also form a network in the PALS (right). ABC technique on cryosection using mAb 10A6. Final magnification, ×69. G: Primary (or tangentially sectioned secondary) follicle stained for MAdCAM-1. In this specimen more branched cells are positive for MAdCAM-1 than in F. There are strongly positive elongated cells in the outer MZ and more weakly staining cells with finer and more elaborate projections in the perifollicular zone. The PALS is located at the bottom. ABC technique on cryosection using mAb 10A6. Final magnification, ×110. H: Higher magnification of MAdCAM-1-positive cells in the PALS. A central arteriole is located to the left. The MAdCAM-1-positive branched cells ensheath bundles of fibers that appear as pale stripes within the brown envelope of immunoreactive cells. No nuclear counterstain. ABC technique on cryosection using mAb 10A6. Final magnification, ×277.