NR AWPB
AU Toppets,V.; Piret,J.; Minne,M.; Grobet,L.; Antoine,N.
TI CNA.42 and FDC-B1, directed against ovine follicular dendritic cells?
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions DIA-55
PT Konferenz-Poster
AB Like the variant of Creutzfeldt-Jakob (vCJD) in human and bovine spongiform encephalopathy (BSE) in cattle, natural scrapie in sheep is a transmissible spongiform encephalopathy (TSE) caused by prions (PrPsc). If natural scrapie is endemic in sheep and considered as harmless for human, the BSE species-specific barrier from cattle to genetically susceptible sheep appears to be non-existent. Sheep orally infected by BSE agent developed similar clinical signs than in natural scrapie infection and the similar tissue tropism of the two agents suggest that BSE could potentially be transmitted from sheep to sheep. Following a peripheral exposure, contrary to BSE agent, PrPsc is widely distributed in all lymph organs. The presence of PrPsc at early time point in tonsils suggests that tonsillar biopsies would have a role in the diagnosis of preclinical stage of the disease. In lymph organs, follicular dendritic cells (FDCs) seem to be the major site of cellular prion protein expression and the principal sites of infectious agent accumulation. Nevertheless, the ability to recognise specifically the network of FDCs from all secondary ovine lymph organs is limited. In this study, two monoclonal antibodies were tested: CNA.42 directed to human FDCs and FDC-B1, directed to bovine FDCs. Palatine and pharyngeal tonsils were removed from sheep at the age 4 to 6 months, processed for immunocytochemistry and florescence microscopy analysis. This one reveals a clearly positive network inside the germinal center of both tonsils immunostained with FDC-B1. However, the CNA.42 only cross-reacts with paryngeal tonsils follicular dendritic cells. These results permit to postulate that the antigen recognised by CNA.42 is not expressed in the same way by follicular dendritic cells from all lymph organs. Negative staining obtained on ovine tonsils with this antibody must thus be interpreted with full knowledge of the facts. Other lymph organs, as lymph nodes from digestive and respiratory tract, will be studied to highlight if this observation is organ specific or not.
AD Department of Morphology and Pathology, Laboratory of Animal Histology-Embryology, Faculty of Veterinary Medecine, University of Liège, Belgium. E-mail: vtoppets@ulg.ac.be
SP englisch
PO Italien