Preclinical Detection of Prions in Blood of Nonhuman Primates Infected with Variant Creutzfeldt-Jakob Disease.

Luis Concha-Marambio,Marcelo A Chacon,Claudio Soto

doi:10.3201/eid2601.181423

Abstract

Variant Creutzfeldt-Jakob disease (vCJD) is caused by prion infection with bovine spongiform encephalopathy and can be transmitted by blood transfusion. Protein misfolding cyclic amplification (PMCA) can detect prions in blood from vCJD patients with 100% sensitivity and specificity. To determine whether PMCA enables prion detection in blood during the preclinical stage of infection, we performed a blind study using blood samples longitudinally collected from 28 control macaques and 3 macaques peripherally infected with vCJD. Our results demonstrate that PMCA consistently detected prions in blood during the entire preclinical stage in all infected macaques, without false positives from noninfected animals, when using the optimized conditions for amplification of macaque prions. Strikingly, prions were detected as early as 2 months postinoculation (>750 days before disease onset). These findings suggest that PMCA has the potential to detect vCJD prions in blood from asymptomatic carriers during the preclinical phase of the disease.

Highlights

Prion diseases are rare and fatal neurodegenerative diseases transmitted by infectious proteinaceous agents called prions, which are composed of a disease-associated misfolded version (PrPSc) of the normally expressed prion protein (PrPC) [1,2,3]
Results m-Variant Creutzfeldt-Jakob disease (vCJD) Prion Conversion of Human PrPC into PrPSc in protein misfolding cyclic amplification (PMCA) We previously showed that PMCA can efficiently amplify vCJD prions using TgHu-PrPC substrate [21]
Because the sequence of macaque and human PrP has 9 aa differences, we first evaluated whether human PrPC could be converted into PrPSc in PMCA by macaque-adapted vCJD (m-vCJD) prions

Summary

Introduction

Prion diseases are rare and fatal neurodegenerative diseases transmitted by infectious proteinaceous agents called prions, which are composed of a disease-associated misfolded version (PrPSc) of the normally expressed prion protein (PrPC) [1,2,3]. PMCA can amplify vCJD prions from brain homogenate (BH) diluted 10–10- to 10–11-fold, reaching a 10–100 billion-fold amplification [21] This level of amplification has allowed detection of prions in blood and urine samples from vCJD patients [21,22], reaching sensitivities and specificities approaching 100% in experiments confirmed in various laboratories [23,24]. It is unclear how early prions can be detected in the blood of infected persons at the preclinical stage of the disease. We analyzed the preclinical detection of prions in blood samples from macaques (Macaca fascicularis) experimentally infected with the vCJD agent as an animal model for infected asymptomatic human carriers

Methods

Results

Conclusion