ARS | Publication request: LOSS OF PRION PROTEIN IMMUNOREACTIVITY AFTER BOILING IN SATURATED CALCIUM HYDROXIDE SOLUTION

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 28, 2004
Publication Date: January 11, 2005
Citation: Greenlee, J.J., Nicholson, E.M., Hamir, A.N., Richt, J.A., Kunkle, R.A., Noyes, G., Hotzapple, M.T., Kehrli Jr., M.E. 2005. Loss of prion protein immunoreactivity after boiling in saturated calcium hydroxide solution [abstract]. Keystone Symposia: Molecular Mechanisms of Transmissible Spongiform Encephalopathies. Poster No. 125.

Technical Abstract: Prions, the infectious agents responsible for transmissible spongiform encephalopathies (TSE), are resistant to destruction by physical, enzymatic, and chemical means. Inactivation of TSE agents or elimination of potential contamination is a significant issue in the disposal of products of animal origin or animal by-products. Chemical means of inactivation such as concentrated hypochlorite (bleach) solutions or sodium hydroxide solution can damage equipment, cause respiratory irritation in workers exposed to fumes, pose problems with disposal, or may not be appropriate for processing large amounts of material. Hydrolysis in boiling saturated calcium hydroxide (limewater) utilizes inexpensive chemicals to digest the protein components of offal. The purpose of this work was to determine if boiling prion containing brain material in limewater would abolish immunoreactivity of the infectious prion as determined by western blot. Brain material from scrapie-infected sheep was digested in boiling limewater for intervals of 15 to 2 hours. Controls processed in parallel included non-scrapie infected brain samples, infectious material boiled in pH corrected limewater, and infectious material prepared by standard methods. Immunoreactivity was abolished in samples processed in boiling limewater for 15 minutes or greater whereas results from homogenates prepared in pH corrected calcium hydroxide were similar to positive control samples. Boiling in limewater may offer an alternative for disposal of carcasses and potential infectious materials. Others have shown that abolishment of immunoreactivity by western blot may correlate poorly with infectivity; so ongoing studies are designed to determine the size of the digested products and the infectivity of these products in a raccoon model of scrapie infection.