Isolation and characterization of new anti-PrP monoclonal antibodies

AGFD 199

Larry H. Stanker, lstanker@pw.usda.gov1, Ana Serban2, Jiri G. Safar, haiti@itsa.ucsf.edu3, Giuseppe Legname, glegname@ind.ucsf.edu2, and Stanley B. Prusiner, Stanley@ind.ucsf.edu3. (1) Foodborne Contaminants Research Unit, USDA-ARS Western Regional Research Center, 800 Buchanan St, Albany, CA 94710, (2) Institute for Neurodegenerative Diseases, University of California at San Francisco, 513 Parnnassus Ave, San Francisco, CA 94143-0518, (3) Institute for Neurodegenerative Diseases, University of California, San Francisco, 513 Parnassus Ave, P.O. Box 0518, San Francisco, CA 94143-0518
The prion diseases (or transmissible spongiform encephalopathies) are fatal neurodegenerative illnesses caused by the accumulation of PrPSc, which is an alternatively folded isoform of the cellular prion protein (PrPC). These disorders are widespread and are found in humans (Creutzfeldt-Jakob disease), in sheep (scrapie), in elk and deer (chronic wasting disease), and in cattle (bovine spongiform encephalopathy) as well as in mink and cats. Detection of PrPSc commonly relies on immunochemical methods. In this study, we isolated antibodies that improved the performance of the conformation-dependent immunoassay (CDI) used to measure both the protease-resistant and -sensitive forms of PrPSc. Following immunization of Prnp-null mice, a multitiered screening strategy was developed and a panel of candidate antibodies identified. Monoclonal antibody binding to PrP from different species, to reduced versus non-reduced PrP, to synthetic peptides, and to denatured PrP suggest that antibodies with both continuous and discontinuous epitopes were isolated. At least one of the antibodies, F4-31, substantially improved performance of the CDI for detection of PrPSc in cattle.