Tuesday, February 15

8:30    Morning Coffee, Poster and Exhibit Viewing

Advances in Diagnostics

9:00    Comments by Session Chairperson
Dr. David Asher, Lab Chief, Lab of Methods Development, FDA

9:10    A Rapid Pre-Symptomatic Diagnostic Test for PrPsc in Tissue and Blood Using Conformationally Sensitive PrP Peptide Ligands
Dr. Cindy S. Orser, Adlyfe, Inc. and Georgetown University
A simple strategy for the specific detection of conformationally altered prion protein in both brain and blood samples has been successfully demonstrated with the Misfolded Protein Diagnostics (MPD) assay. The MPD assay is based on the documented changes to the prion (PrP) protein itself during the progression of the TSE disease process, that is, the conformational conversion from a largely a-helical conformer structure to a b-sheet rich conformer structure. Our preliminary studies successfully demonstrate that the specific detection of the pathologic prion protein can be approached by simple experimental means based on the molecular events leading to aggregate formation. 

9:40    Highly Sensitive TSE ELISA and its Application for Blood Screening
Dr. Alex Raeber, Prionics AG
Routine detection of TSEs in slaughtered animals is performed by rapid tests based on the immunochemical detection of PrPsc in brain tissue. Recently a link between cases of vCJD death and prior blood donation from donors who later developed vCJD has been reported. Currently there is no test available to detect vCJD in blood. A TSE test for blood samples could certainly help strengthen the current safety measures and to retain patient confidence. We have developed a new sandwich ELISA test based on the prion specific antibody 15B3 which does not require a protease digestion step in the sample preparation. Using serial dilutions of brain tissue we have determined the limit of detection to be around 50 infectious units of prion infectivity. This assay is now being used to screen various tissues and body fluids of TSE infected organisms.

10:10   Development of an in vitro TSE Infectivity Assay: Application to Validation of Manufacturing Processes
Dr. Benoit Flan, LFB, Laboratoire Français du Fractionnement et des Biotechnologies
Several cell lines can be infected by prions, including both neuronal and non neuronal cell lines. Here we describe the development of a very sensitive in vitro cell based TSE titration assay. This assay was shown to be suitable for evaluating the TSE infectivity removal in manufacturing processes used for the manufacture of biological products, using a 15nm nanofiltration step as a model which gave reduction factors quite well correlated with previously reported data from experiments performed by bioassay or Western Blot. Interest of such an assay will be discussed as well as further developments for regulatory recognition. Co-Authors: B.YOU, JT AUBIN

10:25   Coffee Break, Poster and Exhibit Viewing

Advances in Prevention, Treatment, Inactivation and Removal

10:55    High-Throughput Screening for Inhibition of PrP-res Production in Cell Culture and Testing against Scrapie in Mice 
Dr. David Kocisko, National Institutes of Health, NIAID, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, Institutes of Health- Rocky Mountain Laboratory 
We have developed high-throughput cell-culture based assays to find inhibitors of protease-resistant prion protein (PrP-res) formation against two strains of mouse scrapie and sheep scrapie. After screening a large library of compounds and many different cyclic tetrapyrroles, we found some potent new inhibitors. Some of the best inhibitors were tested in transgenic mice against scrapie infection and several different cyclic tetrapyrroles have demonstrated significant prophylactic activity.

11:25    A Case Study for the Inactivation of TSE Agents Using an Alkaline Treatment in the Manufacturing Process of a Cell Culture Media Supplement
Mr. Joseph G. Montalto, Senior Director, North American Fractionation Operations, Serologicals Corporation
Transmissible Spongiform Encephalopathy (TSE) is a neurological disease caused by proteinaceous agents called prions. TSE diseases are found in different species including variant Creutzfeldt-Jakob disease (vCJD) in human, scrapie in sheep, and Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease in cattle. Due to the transmissible nature of the diseases, biopharmaceuticals manufactured with bovine-derived materials are perceived as being at risk of transmitting TSE. Strategies to minimize the risk of TSE contamination include addressing the source of animals, the nature of the animal tissue used, and the processing steps of the materials or products.

11:55    Novel Practical Decontamination Methods
Dr. Jean-Philippe Deslys, Service de Neurovirologie, Atomic Energy Commission, France
The unique resistance of prions to decontamination, and evidence that prion diseases can be transmitted iatrogenically on medical devices pose a serious infection control challenge to healthcare facilities. New methods, including an original vaporous hydrogen peroxyde treatment (VHP), have been validated and constitute novel decontamination procedures which can be proposed to ensure the safety of medical and surgical instruments as well as surfaces that cannot withstand the currently recommended harsh prion inactivation procedures.

12:25    Ultra-High Pressure Cooking of TSE-Spiked Meat Products
Dr. Paul W. Brown
Cooking meat products at temperatures in the range of 132°C under pressures of 690 MPa or higher for at least 3 minutes yields a product that in blinded taste tests is judged equal or superior to the same product cooked in an oven. These conditions have been found to reduce the concentration of pathologically misfolded PrPTSE and inactivate ³ 3 logs of infectivity of several different strains of TSE-causing agents. No other commercially practical processing method can ensure a potable and TSE-free product. Recently completed and ongoing studies will be briefly described. Co-Authors: Franco Cardone, Richard Meyer, and Maurizio Pocchiari 

12:35    Close of Conference