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Engineering and Evolution of Synthetic Adeno-Associated Virus (AAV) Gene Therapy Vectors via DNA Family Shuffling
Published on: April 2, 2012
Improved foamy virus vectors with minimal viral sequences
Grant Trobridge1, Neil Josephson, George Vassilopoulos
1Department of Medicine, Division of Hematology, University of Washington, Seattle, Washington 98195, USA.
Molecular Therapy : the Journal of the American Society of Gene Therapy
|September 17, 2002
Summary
High-titer foamy virus (FV) vectors for gene therapy were developed using a transient cotransfection system. These deleted FV (deltaphi) vectors achieve high titers with minimal viral genome, enabling large transgene delivery.
Area of Science:
- Gene Therapy
- Virology
- Molecular Biology
Background:
- Foamy virus (FV) vectors are promising for gene therapy.
- Current FV vectors have limitations, including large genomes and low production titers.
Purpose of the Study:
- To develop a high-titer FV vector system with a minimal genome for gene therapy.
- To overcome limitations of existing FV vectors for efficient gene delivery.
Main Methods:
- Developed a transient cotransfection system using four plasmids for Gag, Pol, Env, and vector expression.
- Engineered deleted foamy (deltaphi) vectors with deletions in non-essential genes and LTR U3 region.
- Introduced stop codons in remaining gag sequences to prevent viral peptide expression.
Main Results:
- Achieved helper-free, unconcentrated deltaphi vector titers exceeding 10(5) transducing units/ml.
- Concentrated deltaphi vector stocks reached titers over 10(7) transducing units/ml.
- Demonstrated utility for large therapeutic genes with a 9.2-kb transgene cassette.
Conclusions:
- The transient cotransfection system enables high-titer production of deltaphi vectors.
- These deltaphi vectors are suitable for gene therapy applications, including delivery of large therapeutic genes.
- The engineered vectors minimize viral components, enhancing safety and efficiency.
