Related Experiment Video
Updated: Jul 16, 2025
Immunohistochemistry Test for the Lyssavirus Antigen Detection from Formalin-Fixed Tissues
Published on: October 26, 2021
SARS-CoV-2 inactivation in laboratory animal tissues with 4% formaldehyde or 5% glutaraldehyde for transfer to
Veronika Pilchová1, Ahmed Elmontaser Mergani1, Sabrina Clever1
1University of Veterinary Medicine Hannover, Hannover, Germany.
Abstract:
The SARS-CoV-2 pandemic required the immediate need to transfer inactivated tissue from biosafety level (BSL)-3 to BSL-1 areas to enable downstream analytical methods. No validated SARS-CoV-2 inactivation protocols were available for either formaldehyde (FA)-fixed or glutaraldehyde (GA)-fixed tissues. Therefore, representative tissue from ferrets and hamsters was spiked with 2.2 × 106 tissue culture infectious dose 50% per ml (TCID50/ml) SARS-CoV-2 or were obtained from mice experimentally infected with SARS-CoV-2. SARS-CoV-2 inactivation was demonstrated with 4% FA or 5% GA at room temperature for 72 hours by a titer reduction of up to 103.8 TCID50/ml in different animal tissues with a maximum protein content of 100 µg/mg and a thickness of up to 10 mm for FA and 8 mm for GA. Our protocols can be easily adapted for validating the inactivation of other pathogens to allow for the transfer of biological samples from BSL-3 areas to BSL-1 laboratories.
Insights
Validated protocols for inactivating SARS-CoV-2 in animal tissues using formaldehyde or glutaraldehyde were developed. These methods enable safe transfer of biosamples from high-containment labs to standard research settings.
Area of Science:
- Virology
- Biosafety
- Pathogen Inactivation
Background:
- The SARS-CoV-2 pandemic necessitated rapid transfer of biological samples from high-containment (BSL-3) to lower-containment (BSL-1) laboratories for analysis.
- Existing protocols for inactivating SARS-CoV-2 in formaldehyde (FA)-fixed or glutaraldehyde (GA)-fixed tissues were not validated.
Purpose of the Study:
- To develop and validate protocols for inactivating SARS-CoV-2 in animal tissues.
- To enable the safe transfer of SARS-CoV-2-infected tissues from BSL-3 to BSL-1 environments.
Main Methods:
- Animal tissues (ferrets, hamsters, mice) were experimentally infected with SARS-CoV-2 or spiked with known viral titers.
- Tissues were fixed using 4% formaldehyde or 5% glutaraldehyde at room temperature for 72 hours.
- Viral inactivation was assessed by measuring the reduction in tissue culture infectious dose 50% (TCID50/ml).
Main Results:
- Both 4% FA and 5% GA effectively inactivated SARS-CoV-2 in various animal tissues.
- A titer reduction of up to 10^3.8 TCID50/ml was achieved.
- The protocols were effective for tissues up to 10 mm thick (FA) and 8 mm thick (GA) with protein content up to 100 µg/mg.
Conclusions:
- Validated protocols using FA or GA can effectively inactivate SARS-CoV-2 in animal tissues.
- These methods facilitate the safe transfer of infected biological samples from BSL-3 to BSL-1 laboratories.
- The developed protocols are adaptable for validating inactivation of other pathogens.
