HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Castle, B. E. Articles by Marsh, R. F. Search for Related Content PubMed PubMed Citation Articles by Castle, B. E. Articles by Marsh, R. F. Agricola Articles by Castle, B. E. Articles by Marsh, R. F.

Effects of Different Methods of Purification on Aggregation of Scrapie Infectivity

B. E. Castle

Department of Veterinary Science, University of Wisconsin-Madison, Madison, Wisconsin 53706, U.S.A.

High levels of scrapie infectivity were found in detergent-insoluble residues of hamster brain purified by either repeated pelleting in 10% NaCl or by separation in Nycodenz® gradients. Titres determined by the method of incubation interval assay were 100-fold higher than titres measured by endpoint dilution assay. The protein profiles and end-labelled RNA examined by one-dimensional polyacrylamide gel electrophoresis were not different from samples prepared from uninfected brain. Preparations produced by repeated pelleting were treated with RNase A and/or 7 M-urea with no loss of scrapie infectivity. However, the infectivity of samples prepared by gradient centrifugation in Nycodenz® were reduced by 2 to 3 log₁₀ LD₅₀ by treatment with RNase A alone but not in combination with SDS. These results suggest that the scrapie agent may be aggregated by methods of purification employing pelleting in high concentrations of salt, or by adding polycations to disaggregated samples.

Present address: DNAX Research Institute, 901 California Avenue, Palo Alto, California 94303, U.S.A.

Received 3 July 1986; accepted 15 September 1986.