title: Biological effects and use of PrPSc- and PrP-specific antibodies generated by immunization with purified full-length native mouse prions.
abstract: The prion agent is the infectious particle causing spongiform encephalopathies in animals and humans and is thought to consist of an altered conformation (PrP(Sc)) of the normal and ubiquitous prion protein PrP(C). The interaction of the prion agent with the immune system, particularly the humoral immune response, has remained unresolved. Here we investigated the immunogenicity of full-length native and infectious prions, as well as the specific biological effects of the resulting monoclonal antibodies (MAbs) on the binding and clearance of prions in cell culture and in in vivo therapy. Immunization of prion knockout (Prnp(0/0)) mice with phosphotungstic acid-purified mouse prions resulted in PrP-specific monoclonal antibodies with binding specificities selective for PrP(Sc) or for both PrP(C) and PrP(Sc). PrP(Sc)-specific MAb W261, of the IgG1 isotype, reacted with prions from mice, sheep with scrapie, deer with chronic wasting disease (CWD), and humans with sporadic and variant Creutzfeldt-Jakob disease (CJD) in assays including a capture enzyme-linked immunosorbent assay (ELISA) system. This PrP(Sc)-specific antibody was unable to clear prions from mouse neuroblastoma cells (ScN2a) permanently infected with scrapie, whereas the high-affinity MAb W226, recognizing both isoforms, PrP(Sc) and PrP(C), did clear prions from ScN2a cells, as determined by a bioassay. However, an attempt to treat intraperitoneally prion infected mice with full-length W226 or with a recombinant variable-chain fragment (scFv) from W226 could only slightly delay the incubation time. We conclude that (i) native, full-length PrP(Sc) elicits a prion-specific antibody response in PrP knockout mice, (ii) a PrP(Sc)-specific antibody had no prion-clearing effect, and (iii) even a high-affinity MAb that clears prions in vitro (W226) may not necessarily protect against prion infection, contrary to previous reports using different antibodies.
authors.affiliation: Friedrich-Loeffler-Institut, Institute of Immunology, Tuebingen, Germany. benjamin.petsch@fli.bund.de
authors.forename: Benjamin
authors.initials: B
authors.lastname: Petsch
authors.forename: Andreas
authors.initials: A
authors.lastname: Müller-Schiffmann
authors.forename: Anna
authors.initials: A
authors.lastname: Lehle
authors.forename: Elizabeta
authors.initials: E
authors.lastname: Zirdum
authors.forename: Ingrid
authors.initials: I
authors.lastname: Prikulis
authors.forename: Franziska
authors.initials: F
authors.lastname: Kuhn
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Raeber
authors.forename: James W
authors.initials: JW
authors.lastname: Ironside
authors.forename: Carsten
authors.initials: C
authors.lastname: Korth
authors.forename: Lothar
authors.initials: L
authors.lastname: Stitz
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use*; D002460:Cell Line; D055256:Infectious Disease Incubation Period; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D017096:Prion Diseases / Q000517:prevention & control*; D000072002:Prion Proteins; D011328:Prions / Q000276:immunology* / Q000302:isolation & purification*; D011485:Protein Binding; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D000072002:Prion Proteins; D011328:Prions; C512657:Prnp protein, mouse