Accumulation of PrPd in lymphoreticular tissues (retropharyngeal lymph nodes) of scrapie infected goats. (a) Intracellular deposits (arrow) in single or few cells in the light zone of a single secondary follicle of a single lymph node were the only indication of infection in some goats. IHC with Bar224 PrP antibody and haematoxylin counterstaining, ×20. (b) In some other animals, accumulation of PrPd was widespread and severe with abundant aggregates associated with follicular dendritic cells and tingible body macrophages. IHC with Bar224 PrP antibody and haematoxylin counterstaining, ×10.