NR AOSL
AU Feraudet,C.; Morel,N.; Simon,S.; Volland,H.; Frobert,Y.; Vilette,D.; Lehmann,S.; Creminon,C.; Grassi,J.
TI Screening of 141 monoclonal antibodies for their capacity to inhibit PrPsc replication in infected cells
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Oral sessions OS-36
PT Konferenz-Vortrag
AB
During the three previous years, several groups have demonstrated that antibodies directed against the prion protein (PrP) can interfere with PrPsc replication in infected cells or delay the onset of prion disease. The results observed, in vivo, in a mouse model using passive immunisation (White et al., 2003, Nature) are, by far, the more significant ones obtained in the field of TSE therapy. The mechanism by which anti-PrP antibodies interfere with PrPsc replication is not clear but the two main hypotheses presented so far, imply either a perturbation of the cellular trafficking of PrPc or the inhibition of the contact between PrPc and PrPsc.
In order to characterize more precisely the therapeutic effect of anti-PrP antibodies, we have screened 141 different monoclonal antibodies produced in our laboratory for their capacity to clean scrapie infected cells (N2a22L) of their PrPsc content. The antibodies tested were
directed against PrP peptides, recombinant PrP, denatured or native Scrapie Associated Fibrils
(SAFs, hamster). All were previously clearly identified as binding PrPc while some of them also showed significant reactivity with SAFs. The screening was performed by incubating infected cells for 3 days in the presence of a 10µg/ml concentration of mabs. At the end of this period, the PrPsc cellular content was determined using a rapid purification method and detection of denatured PrPsc by the means of appropriate sandwich immunoassays. This screening allowed to identify 36 mabs appearing as efficient for cleaning the cells. Among those for which a linear epitope was identified (16), 9 are directed against the octa-repeat region while 7 are directed against the central region of PrP (142-160). In addition, 20 mabs recognizing a conformational unidentified epitope were selected. Further results including the combined use of 2 or 3 mabs
will be presented and the possible consequences of these observations in terms of therapeutic mechanism will be discussed.
AD Cécile Féraudet, Nathalie Morel, Stéphanie Simon, Hervé Volland, Yveline Frobert, Christophe Créminon, Jacques Grassi, CEA, service de Pharmacologie et d'Immunologie, CEA/Saclay, 91191 Gif sur; Didier Vilette, INRA, Virologie Immunologie Moléculaire, 78350 Jouy en Josas, France; Sylvain Lehmann, CNRS, Biologie des Encéphalopathies Spongiformes Transmissibles, 34396
SP englisch
PO Deutschland