Magdalini Polymenidou 1 , Rita Moos 1 , Mike Scott 2 , Christina Sigurdson 1 , Yong-zhong Shi 5 , Bill Yajima 3 , Iva Hafner-Bratkovič 6 , Roman Jerala 6 , 7 , Simone Hornemann 8 , Kurt Wuthrich 8 , 9 , Anne Bellon 10 , Martin Vey 10 , Graciela Garen 3 , 4 , Michael N. G. James 4 , Nat Kav 3 , Adriano Aguzzi 1 , *
8 December 2008
PrP Sc, a misfolded and aggregated form of the cellular prion protein PrP C, is the only defined constituent of the transmissible agent causing prion diseases. Expression of PrP C in the host organism is necessary for prion replication and for prion neurotoxicity. Understanding prion diseases necessitates detailed structural insights into PrP C and PrP Sc. Towards this goal, we have developed a comprehensive collection of monoclonal antibodies denoted POM1 to POM19 and directed against many different epitopes of mouse PrP C. Three epitopes are located within the N-terminal octarepeat region, one is situated within the central unstructured region, and four epitopes are discontinuous within the globular C-proximal domain of PrP C. Some of these antibodies recognize epitopes that are resilient to protease digestion in PrP Sc. Other antibodies immunoprecipitate PrP C, but not PrP Sc. A third group was found to immunoprecipitate both PrP isoforms. Some of the latter antibodies could be blocked with epitope-mimicking peptides, and incubation with an excess of these peptides allowed for immunochromatography of PrP C and PrP Sc. Amino-proximal antibodies were found to react with repetitive PrP C epitopes, thereby vastly increasing their avidity. We have also created functional single-chain miniantibodies from selected POMs, which retained the binding characteristics despite their low molecular mass. The POM collection, thus, represents a unique set of reagents allowing for studies with a variety of techniques, including western blotting, ELISA, immunoprecipitation, conformation-dependent immunoassays, and plasmon surface plasmon resonance-based assays.