title: Infectious prion protein in the filtrate even after 15 nm filtration.
abstract: The evaluation of the removal efficacy during manufacturing is important for the risk assessment of plasma products with respect to possible contamination by infectious prions, as recently reported in several papers on the potential for prion transmission through plasma products. Here, we evaluated a virus removal filter which has 15 nm pores. An antithrombin sample immediately prior to nano-filtration was spiked with prion material prepared in two different ways. The removal (log reduction factor) of prion infectivity using animal bioassays was >or=4.72 and 4.00 in two independent filtrations. However, infectivity was detected in both the pellet and supernatant following ultracentrifugation of the 15 nm filtered samples, indicating difficulty in complete removal. The data supports the conclusion that a certain amount of infectious prion protein is present as a smaller and/or soluble form (less than approximately 15 nm in diameter).
authors.affiliation: Research & Development Division, Benesis Corporation, Kashima, Yodogawa-ku, Osaka, Japan. Yunoki.Mikihiro@mk.mt-pharma.co.jp
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Yunoki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Takeru
authors.initials: T
authors.lastname: Urayama
authors.forename: Yuta
authors.initials: Y
authors.lastname: Kanai
authors.forename: Aya
authors.initials: A
authors.lastname: Nishida
authors.forename: Maki
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ohkubo
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Kawabata
authors.forename: Katsuro
authors.initials: K
authors.lastname: Hagiwara
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Ikuta
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D005591:Chemical Fractionation / Q000379:methods; D006224:Cricetinae; D004340:Drug Contamination; D004868:Equipment Failure; D005374:Filtration / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D008297:Male; D008647:Mesocricetus; D008851:Micropore Filters / Q000592:standards; D010316:Particle Size; D017096:Prion Diseases / Q000097:blood / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary; D011328:Prions / Q000302:isolation & purification*; D014461:Ultracentrifugation / Q000295:instrumentation / Q000379:methods
chemical_list: D011328:Prions