Universal rAAV Reference Standard for qPCR Genome Copy Titer
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Solution Overview
Problem
There is a need for a universal standard and positive control for determining the genome copy titer of recombinant adeno-associated virus (rAAV) particles, as existing methods require separate controls for each rAAV-transgene construct, leading to inefficiencies and increased costs.
Innovation Solution
A recombinant adeno-associated virus (rAAV) vector is developed as a universal reference standard, containing multiple PCR targets flanked by AAV inverted terminal repeats, which can be used across different serotypes to determine genome copy titer through quantitative PCR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate rAAV positive controls are used for each rAAV-transgene construct, then assay accuracy is maintained, but cost and complexity increase
Solution Approach 1:
The patent creates a universal rAAV reference standard that can serve as a positive control for multiple different rAAV-transgene constructs and serotypes in quantitative PCR assays. This single reference standard contains multiple PCR targets flanked by AAV inverted terminal repeats, allowing it to function across different applications rather than requiring separate construct-specific controls for each assay.
2Measurement precision
If separate rAAV positive controls are used for each construct, then construct-specific accuracy is achieved, but time and efficiency decrease
Solution Approach 1:
The universal reference standard eliminates the need to prepare and use separate positive controls for each construct, allowing researchers to assay multiple rAAV-transgene constructs simultaneously using the same reference standard and quantitative PCR protocol, thereby improving throughput and efficiency.
Solution Approach 2:
The reference standard is designed with multiple discrete PCR targets within a single rAAV genome, each target corresponding to different transgene constructs or serotypes. This segmentation allows the single reference standard to provide construct-specific accuracy for multiple different targets through multiplexed or sequential PCR analysis.
3Adaptability or versatility
If multiple separate controls are used, then comprehensive coverage is achieved, but cost increases
Solution Approach 1:
The patent describes a universal reference standard that can be used across multiple rAAV serotypes and transgene constructs, eliminating the need to purchase and maintain separate positive controls for each serotype and construct, thereby reducing overall material costs while maintaining comprehensive coverage.
4Reliability
If construct-specific positive controls are used, then assay specificity is maintained, but standardization across methods is reduced
Solution Approach 1:
The universal reference standard provides a common basis for standardizing quantitative PCR assays across different rAAV serotypes and transgene constructs. By using the same reference standard with known genome copy titer for all assays, laboratories can achieve inter-assay comparability and standardization while maintaining specificity through the multiple PCR targets within the reference standard.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The rAAV vector provides a uniform assay performance, reduces costs, and allows for standardization of quantification methods, enhancing the efficiency and accuracy of genome copy titer determination.
Implementation Method 1
quantitative PCR can be used to determine the genome copy titer of harvested rAAV particles
Data Source
AI summary
Disclosed is a recombinant adeno-associated virus (rAAV) vector that is a universal reference standard in quantitative PCR assays used to determine the genome copy titer of rAAV-transgene particles. The rAAV-Universal Standard vector includes multiple nucleotide sequences that are targets for PCR assays to support polymerization such as fragments of commonly used promoters, enhancers, polyadenylation sequences, and reporter genes found in rAAV constructs. Those multiple targets ensure that there is a positive reaction and thus provide a standard, positive control and calibrator to assure proper performance of the quantitative PCR assays without the need to use a separate reference standard for each particular rAAV particle assayed. The rAAV-Universal Standard is produced in multiple AAV serotypes and may encode a functional reporter gene to further provide a universal positive control for analytical assays of rAAV-transgene particles.