Immunolabeling of PrPScin the retropharyngeal lymph nodes from a scrapie-infected sheep. The FDC-type of PrPSc immunolabeling (dark red) was visible in the light zones of secondary follicles in the retropharyngeal lymph nodes (animal ID 3753) when labeled with all seven anti-prion mAbs; 12B2 (A), P4 (B), 1E4 (C), 8G8 (D), L42 (E), SAF84 (F) and F18.104.22.168 (G). However, such FDC-type of PrPSc labeling was not observed in this animal when paired hemal nodes were labeled with any of these antibodies. [Example; F99/97.6.1 (H) and SAF84 (I)]. Scale bar = 50 μm.