Journal Article

Stability of BSE infectivity towards heat treatment even after proteolytic removal of prion protein

Becher, Dieter, Wageningen BioVeterinary Research ; Wageningen University and Research [Wageningen] (WUR), Department of Poultry Science, College of Agricultural and Life Sciences ; North Carolina State University [Raleigh] (NC State) ; University of North Carolina System (UNC)-University of North Carolina System (UNC), Di Bari, Michele, Shih, Jason, Groschup, Martin, Balkema-Buschmann, Anne, Beekes, Michael, Istituto Superiore di Sanità = National Institute of Health (ISS), Davidse, Aart, North Carolina State University [Raleigh] (NC State) ; University of North Carolina System (UNC), Nonno, Romolo, Interactions hôtes-agents pathogènes [Toulouse] (IHAP) ; Ecole Nationale Vétérinaire de Toulouse (ENVT) ; Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environ

2021

Overview

Abstract The unconventional infectious agents of transmissible spongiform encephalopathies (TSEs) are prions. Their infectivity co-appears with PrP Sc , aberrant depositions of the host’s cellular prion protein (PrP C ). Successive heat treatment in the presence of detergent and proteolysis by a keratinase from Bacillus licheniformis PWD-1 was shown before to destroy PrP Sc from bovine TSE (BSE) and sheep scrapie diseased brain, however data regarding expected reduction of infectivity were still lacking. Therefore, transgenic Tgbov XV mice which are highly BSE susceptible were used to quantify infectivity before and after the bovine brain treatment procedure. Also four immunochemical analyses were applied to compare the levels of PrP Sc . After heating at 115 °C with or without subsequent proteolysis, the original BSE infectivity of 10 6.2–6.4 ID 50 g −1 was reduced to a remaining infectivity of 10 4.6–5.7 ID 50 g −1 while strain characteristics were unaltered, even after precipitation with methanol. Surprisingly, PrP Sc depletion was 5–800 times higher than the loss of infectivity. Similar treatment was applied on other prion strains, which were CWD1 in bank voles, 263 K scrapie in hamsters and sheep PG127 scrapie in tg338 ovinized mice. In these strains however, infectivity was already destroyed by heat only. These findings show the unusual heat resistance of BSE and support a role for an additional factor in prion formation as suggested elsewhere when producing prions from PrP C . Leftover material in the remaining PrP Sc depleted BSE preparation offers a unique substrate for searching additional elements for prion infectivity and improving our concept about the nature of prions.

• Publisher: CCSD,BioMed Central