Scrapie Removal using Planova®Virus Removal Filters

Abstract

As a possible method for reducing the risk of transmissible spongiform encephalopathy (TSE) infection, Planova®virus removal filters were tested for their ability to remove scrapie agent ME7. Albumin solution was spiked with high-titre ME7 and filtered through three different pore sizes of Planova®filters. Infectivity of the pre- and post-filtration samples was assayed in log dilutions by intracerebral inoculation into C57B1/6 mice. Filtration of albumin solution in the absence or presence of a detergent (Sarkosyl) with Planova®35N (35±2nm mean pore size) removed the contaminating scrapie agent with reduction factors of 4·93 log10and 1·61 log10, respectively. Filtration, both in the absence and presence of detergent with Planova®15N (15±2nm mean pore size), and in the presence of detergent with Planova®10N (9±2nm mean pore size), showed high levels of scrapie reduction of >5·87 log10, >4·21 log10, and >3·80 log10, respectively, with no residual infectively detected in any of the filtrate samples. The effectiveness of Planova®35N filtration for the removal of infectivity of this TSE agent is greatly reduced in the presence of a strong detergent, but Planova®filters with 15nm or smaller pore size membranes can remove such infectivity at high reduction rates.