Recombinant AAV Vectors for Enhanced Expression of Authentic IgG

Area of Science:

• Gene Therapy
• Molecular Biology
• Virology

Background:

• Adeno-associated virus (AAV) is a preferred vector for genetic diseases requiring protein replacement.
• Muscle-directed gene transfer using AAV has been explored for delivering protective antibodies.

Purpose of the Study:

• To evaluate and optimize Adeno-associated virus (AAV) vector designs for efficient production of authentic immunoglobulin G (IgG) molecules.
• To compare single-stranded AAV (ssAAV) and self-complementary AAV (scAAV) vector strategies for IgG expression.
• To identify modifications that enhance IgG expression levels and ensure proper protein structure.

Main Methods:

• Compared single-vector ssAAV and two-vector scAAV approaches for rhesus IgG expression.
• Introduced furin cleavage sequence with F2A and woodchuck hepatitis virus post-transcriptional regulatory element (WPRE) into ssAAV vectors.
• Assessed IgG expression levels and protein integrity using cell culture transduction experiments.

Main Results:

• Both one-vector and two-vector AAV approaches achieved significant full-length IgG expression.
• Furin cleavage sequence and WPRE enhanced IgG expression by approximately 2-fold and 1.5-2.0 fold, respectively.
• IgG1 variants showed superior expression compared to IgG2 forms; AAV2 capsid mutations did not improve ssAAV1-mediated IgG expression.

Conclusions:

• Optimized AAV vector designs, incorporating specific sequences, can significantly improve authentic IgG production.
• Findings provide a foundation for rational AAV vector engineering for therapeutic antibody gene transfer.
• Vector design choices, including IgG isotype and regulatory elements, are critical for efficient gene therapy.