title: Measuring prions causing bovine spongiform encephalopathy or chronic wasting disease by immunoassays and transgenic mice.
abstract: There is increasing concern over the extent to which bovine spongiform encephalopathy (BSE) prions have been transmitted to humans, as a result of the rising number of variant Creutzfeldt-Jakob disease (vCJD) cases. Toward preventing new transmissions, diagnostic tests for prions in livestock have been developed using the conformation-dependent immunoassay (CDI), which simultaneously measures specific antibody binding to denatured and native forms of the prion protein (PrP). We employed high-affinity recombinant antibody fragments (recFab) reacting with residues 95-105 of bovine (Bo) PrP for detection and another recFab that recognizes residues 132-156 for capture in the CDI. We report that the CDI is capable of measuring the disease-causing PrP isoform (PrP(Sc)) in bovine brainstems with a sensitivity similar to that of end-point titrations in transgenic (Tg) mice expressing BoPrP. Prion titers were approximately 10(7) ID(50) units per gram of bovine brainstem when measured in Tg(BoPrP) mice, a figure approximately 10 times greater than that determined by bioassay in cattle and approximately 10,000x greater than in wild-type mice. We also report substantial differences in BoPrP(Sc) levels in different areas of the obex region, where neuropathology has been consistently observed in cattle with BSE. The CDI was able to discriminate between PrP(Sc) from BSE-infected cattle and Tg(BoPrP) mice as well as from chronic wasting disease (CWD)-infected deer and elk. Our findings argue that applying the CDI to livestock should considerably reduce human exposure to animal prions.
authors.affiliation: Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143-0518, USA.
authors.forename: Jiri G
authors.initials: JG
authors.lastname: Safar
authors.forename: Michael
authors.initials: M
authors.lastname: Scott
authors.forename: Jeff
authors.initials: J
authors.lastname: Monaghan
authors.forename: Camille
authors.initials: C
authors.lastname: Deering
authors.forename: Svetlana
authors.initials: S
authors.lastname: Didorenko
authors.forename: Julie
authors.initials: J
authors.lastname: Vergara
authors.forename: Haydn
authors.initials: H
authors.lastname: Ball
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Legname
authors.forename: Estelle
authors.initials: E
authors.lastname: Leclerc
authors.forename: Laura
authors.initials: L
authors.lastname: Solforosi
authors.forename: Hana
authors.initials: H
authors.lastname: Serban
authors.forename: Darlene
authors.initials: D
authors.lastname: Groth
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Burton
authors.forename: Stanley B
authors.initials: SB
authors.lastname: Prusiner
authors.forename: R Anthony
authors.initials: RA
authors.lastname: Williamson
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000378:metabolism*; D002417:Cattle; D007562:Creutzfeldt-Jakob Syndrome / Q000378:metabolism / Q000517:prevention & control / Q000635:transmission; D003670:Deer; D004197:Disease Reservoirs; D004199:Disease Vectors; D016643:Encephalopathy, Bovine Spongiform / Q000378:metabolism* / Q000635:transmission; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D051379:Mice; D008822:Mice, Transgenic; D011328:Prions / Q000032:analysis* / Q000145:classification / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013045:Species Specificity; D034081:Wasting Disease, Chronic / Q000378:metabolism* / Q000635:transmission; D015047:Zoonoses
chemical_list: D011328:Prions