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Detection of prions in blood
Joaquín Castilla1, Paula Saá, Claudio Soto
1Department of Neurology, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas, 77555-0646, USA.
Abstract:
Prion diseases are caused by an unconventional infectious agent termed prion, composed mainly of the misfolded prion protein (PrP(Sc)). The development of highly sensitive assays for biochemical detection of PrP(Sc) in blood is a top priority for minimizing the spread of the disease. Here we show that the protein misfolding cyclic amplification (PMCA) technology can be automated and optimized for high-efficiency amplification of PrP(Sc). We show that 140 PMCA cycles leads to a 6,600-fold increase in sensitivity over standard detection methods. Two successive rounds of PMCA cycles resulted in a 10 million-fold increase in sensitivity and a capability to detect as little as 8,000 equivalent molecules of PrP(Sc). Notably, serial PMCA enables detection of PrP(Sc) in blood samples of scrapie-afflicted hamsters with 89% sensitivity and 100% specificity. These findings represent the first time that PrP(Sc) has been detected biochemically in blood, offering promise for developing a noninvasive method for early diagnosis of prion diseases.
Insights
Highly sensitive detection of misfolded prion protein (PrP(Sc)) in blood is now possible using automated protein misfolding cyclic amplification (PMCA). This breakthrough offers a noninvasive diagnostic tool for prion diseases.
Area of Science:
- Neuroscience
- Biochemistry
- Infectious Diseases
Background:
- Prion diseases are fatal neurodegenerative disorders caused by misfolded prion proteins (PrP(Sc)).
- Early and accurate diagnosis is crucial for disease management and preventing transmission.
- Current diagnostic methods lack sensitivity for detecting PrP(Sc) in blood.
Purpose of the Study:
- To develop a highly sensitive assay for biochemical detection of PrP(Sc) in blood.
- To automate and optimize protein misfolding cyclic amplification (PMCA) technology for PrP(Sc) detection.
Main Methods:
- Utilized automated protein misfolding cyclic amplification (PMCA) for PrP(Sc) amplification.
- Employed serial PMCA cycles to enhance detection sensitivity.
- Tested the assay on blood samples from scrapie-afflicted hamsters.
Main Results:
- Achieved a 6,600-fold increase in sensitivity with 140 PMCA cycles.
- Demonstrated a 10 million-fold increase in sensitivity with two serial PMCA rounds, detecting as few as 8,000 PrP(Sc) molecules.
- Detected PrP(Sc) in hamster blood with 89% sensitivity and 100% specificity using serial PMCA.
Conclusions:
- Biochemical detection of PrP(Sc) in blood is feasible using optimized and automated PMCA.
- This method holds promise for a noninvasive diagnostic test for prion diseases.
- The developed assay significantly enhances sensitivity and specificity for PrP(Sc) detection in blood.
