Scrapie removal using Planova® virus removal filters

As a possible method for reducing the risk of transmissible spongiform encephalopathy (TSE) infection, Planova((R)) virus removal filters were tested for their ability to remove scrapie agent MET Albumin solution was spiked with high-titre ME7 and filtered through three different pore sizes of Planova((R)) 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((R)) 35N (35 +/- 2 rim mean pore size) removed the contaminating scrapie agent with reduction factors of 4.93 log(10) and 1.61 log(10), respectively. Filtration, both in the absence and presence of detergent with Planova((R)) 15N (15 +/- 2 rim mean pore size), and in the presence of detergent with Planova((R)) 10N (9 +/- 2 rim mean pore size), showed high levels of scrapie reduction of >5.87 log(10), >4.21 log(10), and >3.80 log(10), respectively, with no residual infectively detected in any of the filtrate samples. The effectiveness of Planova((R)) 35N filtration for the removal of infectivity of this TSE agent is greatly reduced in the presence of a strong detergent, but Planova((R)) filters with 15 rim or smaller pore size membranes can remove such infectivity at high reduction rates. (C) 2001 The International Association for Biologicals.