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Access through your institution Buy or subscribe mRNA vaccines are being preclinically and clinically explored for a variety of conditions. The pharmacokinetics of mRNA-based vaccines can be
assessed by imaging either their delivery vehicles (for example, lipid nanoparticles) or the mRNA itself. However, this approach does not allow quantitative and spatiotemporal measurement
of the protein products of the mRNA — that is, the key bioactive molecules in these vaccines. The PET reporter system is based on _Escherichia coli_ dihydrofolate reductase (eDHFR), a small
(18 kDa) protein tag that can be genetically fused to mRNA. This protein tag specifically binds to the small molecule antibiotic trimethoprim (TMP), which serves as a radiotracer for PET
imaging. “When cells take up eDHFR-tagged mRNA, they express the antigen and tag together in a 1:1 ratio for as long as the genetic material is in the cell”, explains Sellmyer. TMP is then
injected into the body, where it circulates through the bloodstream and major organs. It selectively binds to the genetic tag, while any unbound radiotracer is quickly eliminated from the
body. Therefore, spatiotemporal TMP accumulation is directly related to the level of antigen expression and can be quantitatively assessed by whole-body PET imaging. This is a preview of
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during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support REFERENCES ORIGINAL ARTICLE * Blizard, G. S. et al.
Monitoring mRNA vaccine antigen expression in vivo using PET/CT. _Nat. Commun._ 16, 2234 (2025) Article MATH Google Scholar Download references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS
* Nature Reviews Bioengineering https://www.nature.com/natrevbioeng/ Christine-Maria Horejs Authors * Christine-Maria Horejs View author publications You can also search for this author
inPubMed Google Scholar CORRESPONDING AUTHOR Correspondence to Christine-Maria Horejs. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Horejs, CM. In
vivo tracking of mRNA vaccine antigen expression. _Nat Rev Bioeng_ 3, 269 (2025). https://doi.org/10.1038/s44222-025-00307-4 Download citation * Published: 04 April 2025 * Issue Date: April
2025 * DOI: https://doi.org/10.1038/s44222-025-00307-4 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable
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