Structural and Functional Characterization of Porcine Adeno-Associated Viruses
Austin Nelson1, Mario Mietzsch1, Jane Hsi1
1Department of Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32610, USA.
Viruses
|September 27, 2025
Summary
New non-primate adeno-associated virus (AAV) vectors from pigs show promise for gene therapy. These porcine AAV capsids may overcome pre-existing immunity to primate AAV, enhancing treatment efficacy.
Area of Science:
- Virology
- Structural Biology
- Gene Therapy
Background:
- Current adeno-associated virus (AAV) gene therapies rely on primate-derived capsids.
- Pre-existing neutralizing antibodies against primate AAV limit treatment effectiveness in a significant patient population.
- Non-primate AAVs, including porcine isolates, offer potential alternatives due to sequence divergence.
Purpose of the Study:
- To structurally and functionally characterize novel porcine adeno-associated virus (AAVpo) vectors (AAVpo.1 and AAVpo.6).
- To evaluate the potential of these porcine AAV capsids as alternative gene therapy vectors, particularly for individuals with pre-existing anti-primate AAV immunity.
- To assess the interaction of porcine AAV capsids with human antibodies and identify potential glycan receptors.
Main Methods:
- Production of AAV vectors using a standard triple transfection system with HEK293 cells.
- Purification of AAV vectors via iodixanol density gradient ultracentrifugation.
- Determination of AAVpo.1 and AAVpo.6 capsid structures using cryo-electron microscopy and comparison with known AAV structures (AAV5, AAV9).
- Functional characterization including assessment of human cell infectivity, blood-brain barrier crossing potential, glycan receptor identification, and reactivity to human anti-AAV antibodies.
Main Results:
- Cryo-electron microscopy determined the capsid structures of AAVpo.1 and AAVpo.6.
- Structural comparison revealed sequence divergence from primate AAV serotypes.
- Functional studies assessed infectivity, blood-brain barrier potential, and antibody reactivity, indicating potential for therapeutic use.
- Porcine AAVpo.6 demonstrated potential for human cell infection and blood-brain barrier crossing.
Conclusions:
- Porcine adeno-associated virus (AAVpo) capsids, specifically AAVpo.1 and AAVpo.6, possess unique structural features.
- These porcine AAV vectors exhibit potential for gene therapy applications, especially in patients with pre-existing immunity to primate AAVs.
- Further research into porcine AAVs could expand the toolkit for effective gene therapy delivery.
