Prion seeding activity in DNA extractions: implications for laboratory biosafety.

Area of Science:

• Neuroscience
• Biochemistry
• Microbiology

Background:

• Infectious prions (PrPSc) resist standard degradation methods like proteinase K (PK).
• Nucleic acid extracts are typically considered non-infectious, lacking conventional pathogens.
• The potential for PrPSc co-purification in DNA extraction remains an unrecognized biosafety concern.

Purpose of the Study:

• To investigate if commercial DNA extraction kits co-purify infectious prions (PrPSc).
• To assess the biosafety risks associated with DNA purification from prion-infected tissues.

Main Methods:

• Two laboratories independently tested filter-based and magnetic bead-based DNA extraction kits.
• Tissues from chronic wasting disease (CWD)-positive white-tailed deer and prion-infected hamster brains were used.
• PrPSc seeding activity in DNA eluates and source tissues was measured using real-time quaking-induced conversion (RT-QuIC).

Main Results:

• Commercial DNA extraction kits were ineffective at eliminating PrPSc.
• Substantial agreement was found between PrPSc seeding activity in DNA eluates and source tissues.
• RT-QuIC detected PrPSc in DNA eluates, confirming carry-over into purified DNA.

Conclusions:

• Standard DNA extraction kits do not eliminate PrPSc, posing a potential biosafety risk.
• DNA eluates from PrPSc-positive tissues may retain infectivity.
• Appropriate biosafety protocols are crucial when handling DNA from prion-affected sources.