Immunolabeling in lymphoreticular tissues. a) Distal ileum. Large, intensely labelled PrPSc deposits in macrophages in the germinal centres of Peyer's patch follicles (centre bottom) and the overlying dome (arrows). Diffuse, branching PrPd deposits are consistent with labeling of follicular dendritic cells. Scale bar 100 μm. b) Mesenteric lymph node. Macrophage and follicular dendritic cell labeling, as well as putative veiled afferent dendritic cells in the subcapsular and interfollicular areas (arrows). Scale bar 100 μm.