Open AccessAssessment of the Genetic Susceptibility of Sheep to Scrapie by Protein Misfolding Cyclic Amplification and Comparison with Experimental Scrapie Transmission Studies
Author(s) -
Cecilia Bucalossi,
Gian Mario Cosseddu,
Claudia D’Agostino,
Michele Angelo Di Bari,
Barbara Chiappini,
Michela Conte,
Francesca Rosone,
Luigi De Grossi,
Gaia Scavia,
Umberto Agrimi,
Romolo no,
Gabriele Vaccari
Publication year - 2011
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.00241-11
Subject(s) - scrapie , biology , genotype , in vivo , genetics , in vitro , incubation , incubation period , virology , microbiology and biotechnology , prion protein , gene , disease , pathology , biochemistry , medicine
The susceptibility of sheep to scrapie is influenced mainly by the prion protein polymorphisms A136V, R154H, and Q171R/H. Here we analyzed the ability of protein misfolding cyclic amplification (PMCA) to model the genetic susceptibility of sheep to scrapie. For this purpose, we studied the efficiency of brain homogenates from sheep with different PrP genotypes to support PrPSc amplification by PMCA using an ARQ/ARQ scrapie inoculum. The results were then compared with those obtainedin vivo using the same sheep breed, genotypes, and scrapie inoculum. Genotypes associated with susceptibility (ARQ/ARQ, ARQ/AHQ, and AHQ/ARH) were able to sustain PrPSc amplification in PMCA reactions, while genotypes associated with resistance to scrapie (ARQ/ARR and ARR/ARR) were unable to support thein vitro conversion. The incubation times of the experimental infection were then compared with thein vitro amplification factors. Linear regression analysis showed that the efficiency ofin vitro PrPSc amplification of the different genotypes was indeed inversely proportional to their incubation times. Finally, the rare ARQK176 /ARQK176 genotype, for which noin vivo data are available, was studied by PMCA. No amplification was obtained, suggesting ARQK176 /ARQK176 as an additional genotype associated with resistance, at least to the isolate tested. Our results indicate a direct correlation between the ability of different PrP genotypes to undergo PrPC -to-PrPSc conversion by PMCA and theirin vivo susceptibility and point to PMCA as an alternative to transmission studies and a potential tool to test the susceptibility of numerous sheep PrP genotypes to a variety of prion sources.