Structural Study of Aavrh.10 Receptor and Antibody Interactions

Area of Science:

• * Molecular and structural biology
• * Gene therapy vectorology
• * Virology

Background:

• * Recombinant adeno-associated virus (rAAV) vectors are crucial for gene therapy, delivering therapeutic genes.
• * AAV vector efficacy depends on evading neutralizing antibodies and binding target cell receptors.
• * Structural details of AAVrh.10 receptor binding and antigenicity were previously uncharacterized.

Purpose of the Study:

• * To structurally analyze the binding sites of AAVrh.10 for sulfated N-acetyllactosamine (LacNAc) and neutralizing monoclonal antibodies (MAbs).
• * To understand the antigenicity of the AAVrh.10 capsid.
• * To engineer AAVrh.10 variants that evade antibody neutralization while retaining infectivity.

Main Methods:

• * Cryo-electron microscopy and 3D image reconstruction were employed.
• * Binding sites for LacNAc and four MAbs were mapped.
• * AAVrh.10 capsid surface was engineered to create antibody-evading variants.

Main Results:

• * LacNAc binds to a conserved pocket on the AAVrh.10 capsid's 3-fold protrusion, similar to AAV9's galactose-binding site.
• * AAVrh.10 binds to cell surface glycans containing terminal galactose.
• * Several anti-AAV8 MAbs cross-react with AAVrh.10, binding to the 3-fold capsid protrusions.

Conclusions:

• * Structural insights into AAVrh.10 receptor and antibody interactions were elucidated.
• * Engineered AAVrh.10 variants demonstrate the potential to overcome pre-existing neutralizing antibodies.
• * Findings support the clinical application and biologics approval of AAVrh.10-based gene therapy vectors.