Recombinant AAV Capsid Mutations for Cross-Species Gene Transfer
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Solution Overview
Problem
Current AAV-2 vectors face limitations such as inefficient transduction of clinically relevant cell types, high immunogenicity in humans due to prior exposure, and the need for surrogate serotypes in preclinical studies across species, leading to higher costs and time in development.
Innovation Solution
Development of a recombinant AAV capsid protein (AAV-AM) derived from multiple AAV serotypes with a specific amino acid modification, enhancing transduction efficiency and reducing immunogenicity, allowing cross-species compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AAV-2 vectors are used for gene transfer, then stable long-term transgene expression is achieved, but transduction efficiency in clinically relevant cell types is poor and immunogenicity is high
Solution Approach 1:
The patent applies parameter changes by modifying the capsid protein sequence through site-directed mutagenesis, specifically changing amino acid residues at positions 266 and 316 to alter the surface charge properties of the AAV capsid. This changes the electrostatic interaction parameters between the virus and target cells, improving transduction efficiency while preserving stable transgene expression
Solution Approach 2:
The invention creates a composite capsid structure by combining elements from different AAV serotypes (AAV-2 and AAV-8) to form a chimeric capsid. This composite structure integrates the stable transduction properties of AAV-2 with the enhanced cell type specificity of AAV-8, achieving both reliable long-term expression and improved transduction efficiency
2Adaptability or versatility
If AAV-2 vectors are used, then gene transfer capability is established, but neutralization by pre-existing human antibodies occurs in up to 67% of seropositive individuals
Solution Approach 1:
The patent changes the immunogenic parameters of the AAV capsid by modifying amino acid sequences that are recognized by neutralizing antibodies. The specific mutations at positions 266 and 316 alter the epitope structure, reducing recognition by pre-existing human antibodies while preserving viral function and gene transfer capability
3Adaptability or versatility
If surrogate serotypes are used in preclinical rodent studies, then gene transfer can be performed, but development time and costs increase
Solution Approach 1:
The patent creates a universal AAV vector system with enhanced cross-species transduction capability. The modified capsid proteins enable efficient gene transfer in both rodent and human cells, eliminating the need for surrogate serotypes in preclinical studies and allowing direct translation from rodent to human research
Data Source
AI summary
Recombinant adeno-associated viral (rAAV) vectors expressing recombinant capsid proteins, having enhanced transduction properties in humans and mice are provided. Methods for generating the rAAV capsid proteins and assays to assess transduction efficiency are also provided. Also described are methods for determining the therapeutic efficacy for a gene of interest in two species of mammals by delivering to them the rAAV carrying the gene of interest encapsidated in the recombinant capsid protein.