Characterisation of monoclonal antibodies discriminating the glycoforms and alleles of the sheep prion protein

Abstract

Transmissible spongiform encephalopathies (TSE)are fatal neurodegenerative diseases characterised bythe accumulation in the brain of an abnormal form ofthe host PrP protein. PrP is a cell surface protein withtwo glycosylation sites. Susceptibility to sheep scrapie,the most widely spread TSE, is controlled by a polymorphismof the ovine Prnp gene at amino acid positions136, 154 and 171. Different studies have shownthat the efficiency of conversion of normal PrP (PrPc)into the disease-associated form (PrPsc) is influencedby its carbohydrate moiety and also by its amino acidsequence.In the present work, we characterised four glycoform-dependent monoclonal antibodies raised againstsheep PrP. We demonstrate that these antibodies discriminatethe PrP monoglycosylated species.Interestingly, the recognition of PrP by two of theseantibodies was strongly influenced by the amino acidpresent at position 171, i.e. either Gln or Arg. Thispolymorphism is known as being the main determinantof susceptibility (Glutamine, Q171) and resistance(Arginine, R171) to scrapie in sheep.In conclusion, the monoglycoform-assigned and theallotype-restricted antibodies described here, shouldprovide further opportunities to investigate the involvementof each glycan chain into PrP conversion in relationwith prion strain diversity. They might also be ofinterest for fast animal geneotype typing and forunderstanding the basis of the resistance conferred bythe presence of Arginine at amino-acid 171 of PrP.