NR ATIO
AU Didier,A.; Dietrich,R.; Steffl,M.; Pfaff,E.; Märtlbauer,E.; Amselgruber,W.M.
TI Bovine prion protein in the mammary gland: an mRNA and protein expression study
QU International Conference - Prion 2005: Between fundamentals and society's needs - 19.10.-21.10.2005, Congress Center Düsseldorf - Poster Session: Cell Biology of PrPc and PrPsc CELL-46
PT Konferenz-Poster
AB
Since the pathogenic isoform of bovine prion protein (PrPsc) is supposed to be the causative agent for development of variant Creutzfeldt-Jakob Disease (vCJD) in humans, many efforts have been made to elucidate transmission risk caused by foodstuffs of bovine origin. Variant CJD cases due to consumption of milk and milk products have not yet been described.
Present study aimed to determine cellular PrP content and localisation in the mammary gland of cattle for basic risk assessment concerns. Udder tissue of a total of 9 cows was assayed by real-time RT-PCR, ELISA and immunohistochemistry. Results showed strong individual differences in mRNA and protein expression. Immunolocalisation of PrPc revealed selective and strong positive staining of lactocytes. Intensity of PrPc expression varies between individual alveoles and is found particularly strong in active columnar cells, reduced in low cuboidal lactocytes and not found in cells lining intralobular and interlobular ducts. Cytoplasmatic prion protein expression was found with preference to the basal cell compartment. Interestingly lymphoid cells of the mammary gland failed to express PrPc at immunohistochemicaly detectable level.
PrPc expression seems to be dependent from actively secreting columnar lactocytes. In these cells cytoplasmatic membranes such as endoplasmatic reticulum and Golgi tremendously increase mainly in the basal half of the cell at the beginning of the lactation period. PrPc itself is known to be synthesised in ER and Golgi before it is integrated in the cell membrane. This may account to intensive basal staining of cell seen in active alveoles and lobules. Furthermore PrPc is supposed to exhibit superoxide dismutase activity or act as a co-factor in antioxidant pathways. In lactocytes it may therefore contribute to antioxidant protection of milk constituents especially milk lipids.
IN Mittels Echtzeit-PCR mit mRNA, ELISA und Immunhistochemie an Eutergewebe von 9 Kühen fanden die Autoren sowohl von Kuh zu Kuh als auch zwischen den Alveolen (Milchbläschen) große individuelle Unterschiede hinsichtlich der Transkription und Translation bzw. posttranslationale Prozession des Prionproteins. Immunhistochemisch wurde das PrPc selektiv und stark in Laktozyten (sekretorische Brustdrüsenepithelzellen) markiert. Besonders stark ist die Expression des Prionproteins in aktiv Milch produzierenden Laktozyten. Kein PrPc fanden sie in den Zellen des vaskulären Systems sowie in Lymphozyten.
AD Andrea Didier, Richard Dietrich, Erwin Märtlbauer, Ludwig Maximillians Universität München, Germany; Martin Steffl, Werner Amselgruber, Universität Hohenheim, Gemany; Eberhard Pfaff, FLI Bundesforschungsinstitut für Tiergesundheit
SP englisch
PO Deutschland
OR Tagungsband