Related Experiment Video
Updated: Sep 20, 2025
Using Lipid Nanoparticles for the Delivery of Chemically Modified mRNA into Mammalian Cells
Published on: June 10, 2022
Lipid nanoparticle delivery of unmodified mRNAs encoding multiple monoclonal antibodies targeting poxviruses in
Eric M Mucker1, Carolin Thiele-Suess2, Patrick Baumhof2
1Virology Division, United States Army Medical Institute of Infectious Diseases, Fort Detrick, MD 21702, USA.
Abstract:
Poxviruses are a large and complex family of viruses with members such as monkeypox virus and variola virus. The possibility of an outbreak of monkeypox virus (or a related poxvirus) or the misuse of variola virus justifies the development of countermeasures. Furthermore, poxviruses can be a useful surrogate for developing technology involving antibody therapies. In our experiments, we explored the feasibility of utilizing unmodified mRNA that encodes three previously described monoclonal antibodies, c8A, c6C, and c7D11, as countermeasures to smallpox in a relatively large (>3 kg) laboratory animal (rabbits). We confirmed in vitro translation, secretion, and biological activity of mRNA constructs and identified target monoclonal antibody levels from a murine vaccinia virus model that provided a clinical benefit. Individually, we were able to detect c7D11, c8A, and c6C in the serum of rabbits within 1 day of an intramuscular jet injection of lipid nanoparticle (LNP)-formulated mRNA. Injection of a combination of three LNP-formulated mRNA constructs encoding the three different antibodies produced near equivalent serum levels compared with each individual construct administered alone. These data are among the first demonstrating the feasibility of launching multiple antibodies using mRNA constructs in a large, nonrodent species. Based on empirically derived target serum level and the observed decay rate, the antibody levels attained were unlikely to provide protection.
Insights
Messenger RNA (mRNA) can deliver multiple antibodies for poxvirus countermeasures. However, antibody levels in rabbits were insufficient for protection against smallpox.
Area of Science:
- Virology
- Immunology
- Biotechnology
Background:
- Poxviruses, including monkeypox and variola virus, pose potential public health threats.
- Development of countermeasures against poxviruses is crucial due to outbreak risks and potential misuse.
- Poxviruses serve as valuable models for advancing antibody-based therapies.
Purpose of the Study:
- To assess the feasibility of using unmodified mRNA encoding monoclonal antibodies (c8A, c6C, c7D11) as smallpox countermeasures.
- To evaluate the in vitro and in vivo performance of mRNA constructs in a large animal model.
- To determine if multiple antibody-encoding mRNA constructs can be delivered effectively.
Main Methods:
- In vitro confirmation of mRNA translation, secretion, and antibody biological activity.
- Identification of protective monoclonal antibody levels using a murine vaccinia virus model.
- Intramuscular jet injection of lipid nanoparticle (LNP)-formulated mRNA encoding three monoclonal antibodies in rabbits (>3 kg).
- Serum level monitoring of individual and combined antibodies post-injection.
Main Results:
- Successful in vitro translation, secretion, and biological activity of mRNA constructs were confirmed.
- Monoclonal antibodies c7D11, c8A, and c6C were detected in rabbit serum within 1 day of LNP-mRNA injection.
- Co-administration of three LNP-formulated mRNA constructs resulted in serum antibody levels comparable to individual injections.
- Attained antibody levels were deemed unlikely to provide protection based on target serum levels and decay rates.
Conclusions:
- Demonstrated feasibility of delivering multiple antibodies via mRNA constructs in a large, nonrodent species (rabbits).
- While technically feasible, the achieved antibody concentrations were insufficient for therapeutic protection against poxviruses.
- Further optimization is needed to reach protective antibody titers for effective poxvirus countermeasures.
