Ultra-sensitive detection of prion protein fibrils by flow cytometry in blood from cattle affected with bovine spongiform encephalopathy.
BACKGROUND
The definite diagnosis of prion diseases such as Creutzfeldt-Jakob disease (CJD) in humans or bovine spongiform encephalopathy (BSE) in cattle currently relies on the post mortem detection of the pathological form of the prion protein (PrPSc) in brain tissue. Infectivity studies indicate that PrPSc may also be present in body fluids, even at presymptomatic stages of the disease, albeit at concentrations well below the detection limits of currently available analytical methods.


RESULTS
We developed a highly sensitive method for detecting prion protein aggregates that takes advantage of kinetic differences between seeded and unseeded polymerization of prion protein monomers. Detection of the aggregates was carried out by flow cytometry. In the presence of prion seeds, the association of labelled recombinant PrP monomers in plasma and serum proceeds much more efficiently than in the absence of seeds. In a diagnostic model system, synthetic PrP aggregates were detected down to a concentration of approximately 10(-8) nM [0.24 fg/ml]. A specific signal was detected in six out of six available serum samples from BSE-positive cattle.


CONCLUSIONS
We have developed a method based on seed-dependent PrP fibril formation that shows promising results in differentiating a small number of BSE-positive serum samples from healthy controls. This method may provide the basis for an ante mortem diagnostic test for prion diseases.
Trieschmann
Lothar
L
ACGT ProGenomics AG, Weinbergweg 22, D-06120 Halle (Saale), Germany. lothar.trieschmann@acgt-progenomics.de
Navarrete Santos
Alexander
A
Kaschig
Katja
K
Torkler
Sandra
S
Maas
Elke
E
Schätzl
Hermann
H
Böhm
Gerald
G
D000818:Animals; D001709:Biotechnology / Q000379:methods*; D002417:Cattle; D002454:Cell Differentiation; D016643:Encephalopathy, Bovine Spongiform / Q000097:blood* / Q000175:diagnosis*; D005434:Flow Cytometry / Q000379:methods*; D007700:Kinetics; D011328:Prions / Q000097:blood* / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D012680:Sensitivity and Specificity; D013997:Time Factors
D011328:Prions; D011994:Recombinant Proteins