<p>(A) PrP<sup>Sc</sup> immunolabelling (8G8 monoclonal antibody- DAB brown deposit – bar: 80 µm) in mammary gland from a ewe incubating scrapie (preclinical phase – 15 months old – ARQ/ARQ genotype) and harbouring lympho-proliferative mastitis with ectopic lymphoid follicles (Foll.). In the milk ducts lumen (arrow heads), several PrP<sup>Sc</sup> positive cells are identifiable. (B) In mammary gland acini (Aci.), positive PrP<sup>Sc</sup> staining can be observed; either associated with cells or distributed as free granules. (C) Double labelling for PrP<sup>Sc</sup> (R521 polyclonal serum – black deposits) and CD68 (KiM6 clone – red deposits) indicates that intracellular PrP<sup>Sc</sup> in milk ducts and acini lumen is associated with phagocytic cells. (D) PrP<sup>Sc</sup> immunolabelling (8G8 anti-PrP antibody – DAB brown deposit- bar: 200 µm) and (E) PET blot (SHa31 antibody – NBT/BCIP black deposits – bar: 200 µm) of two successive mammary gland sections confirmed that material in milk ducts is proteinase K resistant (arrow heads indicate lining).</p
