title: Infectivity in skeletal muscle of cattle with atypical bovine spongiform encephalopathy.
abstract: The amyloidotic form of bovine spongiform encephalopathy (BSE) termed BASE is caused by a prion strain whose biological properties differ from those of typical BSE, resulting in a clinically and pathologically distinct phenotype. Whether peripheral tissues of BASE-affected cattle contain infectivity is unknown. This is a critical issue since the BASE prion is readily transmissible to a variety of hosts including primates, suggesting that humans may be susceptible. We carried out bioassays in transgenic mice overexpressing bovine PrP (Tgbov XV) and found infectivity in a variety of skeletal muscles from cattle with natural and experimental BASE. Noteworthy, all BASE muscles used for inoculation transmitted disease, although the attack rate differed between experimental and natural cases (∼70% versus ∼10%, respectively). This difference was likely related to different prion titers, possibly due to different stages of disease in the two conditions, i.e. terminal stage in experimental BASE and pre-symptomatic stage in natural BASE. The neuropathological phenotype and PrP(res) type were consistent in all affected mice and matched those of Tgbov XV mice infected with brain homogenate from natural BASE. The immunohistochemical analysis of skeletal muscles from cattle with natural and experimental BASE showed the presence of abnormal prion protein deposits within muscle fibers. Conversely, Tgbov XV mice challenged with lymphoid tissue and kidney from natural and experimental BASE did not develop disease. The novel information on the neuromuscular tropism of the BASE strain, efficiently overcoming species barriers, underlines the relevance of maintaining an active surveillance.
authors.affiliation: Instituto Di Ricoveroe Cura a Carattere Scientifico (IRCCS), Foundation Carlo Besta Neurological Institute, Milano, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Suardi
authors.forename: Chiara
authors.initials: C
authors.lastname: Vimercati
authors.forename: Cristina
authors.initials: C
authors.lastname: Casalone
authors.forename: Daniela
authors.initials: D
authors.lastname: Gelmetti
authors.forename: Cristiano
authors.initials: C
authors.lastname: Corona
authors.forename: Barbara
authors.initials: B
authors.lastname: Iulini
authors.forename: Maria
authors.initials: M
authors.lastname: Mazza
authors.forename: Guerino
authors.initials: G
authors.lastname: Lombardi
authors.forename: Fabio
authors.initials: F
authors.lastname: Moda
authors.forename: Margherita
authors.initials: M
authors.lastname: Ruggerone
authors.forename: Ilaria
authors.initials: I
authors.lastname: Campagnani
authors.forename: Elena
authors.initials: E
authors.lastname: Piccoli
authors.forename: Marcella
authors.initials: M
authors.lastname: Catania
authors.forename: Martin H
authors.initials: MH
authors.lastname: Groschup
authors.forename: Anne
authors.initials: A
authors.lastname: Balkema-Buschmann
authors.forename: Maria
authors.initials: M
authors.lastname: Caramelli
authors.forename: Salvatore
authors.initials: S
authors.lastname: Monaco
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Zanusso
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Tagliavini
mesh_terms: D000686:Amyloidosis / Q000473:pathology; D000818:Animals; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000473:pathology* / Q000635:transmission; D007150:Immunohistochemistry; D007668:Kidney / Q000473:pathology; D008221:Lymphoid Tissue / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D018482:Muscle, Skeletal / Q000473:pathology*; D018620:PrPSc Proteins / Q000472:pathogenicity*
chemical_list: D018620:PrPSc Proteins