Adeno-associated virus (AAV) is one of the most used gene therapy vehicles. It originates from the Dependovirus genus of the Parvovirus family and consists of a nonenveloped, icosahedral protein shell and a small, single-stranded DNA genome of approximately 4.8 kb. This small virus is inherently defective in replication and requires the assistance of a helper virus or some form of genotoxic stress to replicate within the host nucleus. At least eleven AAV serotypes have been identified, of which the most characterized and commonly used for gene delivery is AAV2. Each serotype of AAV has its own characteristic capsid with specific affinity for certain host cell receptors. AAV2 has a high affinity for the receptor heparan sulfate proteoglycan (HSPG), which is expressed in a variety of cell types. AAV5 can bind to the platelet-derived growth factor receptor (PDGFR), which is commonly found on cells in the brain, lung, and retina. AAV1, AAV6, AAV7, and AAV8 are attracted to muscle, lung, muscle, liver, and liver cells, respectively. Each AAV serotype has different tissue-specific targeting, which allows researchers to engineer AAV vectors to deliver therapeutic genes to specific tissues or organs, thereby improving the precision and efficacy of gene therapies. The use of AAV vectors in gene therapy is constantly increasing, and the determination of AAV capsid titer is critical for gene therapy research and development.
Determination of AAV Capsid Titers
Amerigo Scientific offers AAV ELISA kits for determination of full and empty capsids of the most commonly used AAV serotypes including 1, 2, 3, 5, 6, 8, 9, and rh10.
Product Range
Product Benefits
The workflow of ELISA assays is similar for all AAV serotypes and does not require expensive equipment or special training. Single-break strips that can be used separately for different test runs are included.
The ELISA kits are easy to implement into all workflows. With the Xpress ELISA kit in particular, results can be obtained in less than 2 hours without compromising performance.
The exclusive particle antibodies in the ELISA kits recognize native, non-denatured AAV capsids (full and empty) for the quantification of intact AAV particles.
With our ELISA kits, reproducible data can be generated, and low inter- and intra-assay variance (a coefficients of variation (CV) below 10%) can be easily achieved.
AAV2 and AAV8 ELISA kits are based on the ATCC international reference standard material, and all other ELISA kits for AAV1, 3, 5, 6, 9, and rh10 follow an internal gold standard.
The kits can be validated for use in a GMP setting and adhere to FDA guidelines for AAV gene therapy development.
ELISA Principle
The assay is based on a sandwich ELISA technique in which monoclonal antibodies specific for conformational epitopes on assembled AAV capsids are coated on plates and used to capture AAV particles from the sample.
Detection of captured AAV particles is a two-step process. First, the biotin-conjugated monoclonal antibodies bind to the captured AAV particles. In the second step, the streptavidin peroxidase conjugates react with the biotin molecules, and the addition of the substrate causes a color reaction that is proportional to the number of specifically bound virus particles.
AAV ELISA Kits
Standard ELISA kits are available for quantification and detection of full and empty AAV capsids. The capture-antibodies can specifically bind to conformational epitopes that are present on assembled capsid proteins.
AAV Xpress ELISA Kits
AAV Xpress ELISA kits are designed to meet the demand for fast results and time saving. Xpress ELISA kits are developed based on the standard ELISA kits, showing equal accuracy and reproducibility. The composition of the core characteristics is not changed. The difference is that the assay time can be reduced to less than 2 hours using the Xpress ELISA kits, thus achieving the ability to process more samples in a shorter time.
AAV ELISA Controls
Amerigo Scientific also offers reliable positive controls for AAV ELISAs. The AAV ELISA controls consist of fully assembled empty AAV capsids representing serotype-specific conformational epitopes and are therefore reliable positive controls in the detection and quantification assays based on AAV antibodies against conformational epitopes. These AAV ELISA controls have been characterized according to the internal reference standard materials.
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