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AAV ELISA FAQs

In house validation shows that our PROGEN AAV ELISA kits can be used under GMP conditions. However, it is also necessary to validate kits under your individual conditions. If you need support with your validation you can contact us at support@progen.com. 
Performance data is available here.

Yes, some of the antibodies used in our ELISA kits show cross-reactivity with other serotypes. 

For more information on cross-reactivity of our antibodies, please visit our AAV particle antibody webpage.

For example, the AAV8 ELISA kits cross-react with AAVrh10. However, the AAV8 ELISA kit is not suitable for quantification of the total AAV capsid content of AAVrh10 preparations e.g. due to its serotyp-specific kit control. For quantification of AAVrh10 PROGEN offers an ELISA optimized for AAVrh10 containing AAVrh10 kit control. 

With a suitable kit control an ELISA kit can be validated for a specific serotyp. For example, PROGEN offers the AAVrh74 Kit control, which can be used in combination with our AAVrh10 ELISA kit to quantify AAVrh74 capsids. This specific applications needs to be qualified by the user. 

The recognition of shuffled AAV vectors depends on the specific capsid region which is affected by the shuffling. The antibodies used for PROGEN’s AAV ELISAs bind to specific conformational epitopes. These epitopes are generated by the capsid assembly of the corresponding AAV serotypes. 

 
A first indication that the antibody recognizes your shuffled AAV vector is the presence of the antibody-binding epitope. However, changes in protein sequences of the capsid proteins might also influence conformation of the proteins and furthermore the conformation of the epitopes presented on the AAV capsid. Thus, binding affinity of the antibody and determination of the titer based on our Kit Control (non-shuffled) might be influenced and affected. 
 
To test if your shuffled variant is detected by one of our PROGEN antibodies you can either use our antibody sample size and perform a dot blot or you can easily check the binding affinity with our Dip'n'Check lateral flow assay.
 
Since these properties strongly depend on the specific shuffling performed, PROGEN cannot guarantee successful and precise quantification of your shuffled AAV vector. Even if the antibody binding epitopes are still present on your shuffled AAV capsid, your ELISA assay needs to be tested and optimized for your specific AAV vector. PROGEN recommends the production and calibration of a suitable (shuffled) Kit Control, to ensure reliable titer determination of your individually shuffled AAV vector.

 
For more information on the antibody binding epitopes on assembled AAV1, 2, 5, 8 and 9 capsids, see the tables below summarizing the published data from the following publications on the specific antibody binding sites:
 
Residues for A20 and ADK8 binding
 
Contact sides and footprint residues for ADK1a/1b
 
Contact sides and footprint residues for ADK5a/5b
 
AAV1:
 
AAV2
 
AAV5
 
AAV8

Yes, PROGEN offers serotype-specific AAV ELISA Controls for the standardization of your AAV titer determination.

The serotype-specific positive controls are fully characterized empty AAV capsids standardized with PROGEN´s internal gold standards* (AAV1, AAV3, AAV5, AAV6, AAV9, AAVrh10 and AAVrh74) or the ATCC international gold standard material (AAV2 & AAV8).

 

*For more information on PROGEN´s internal gold standard, take a look at our posters "Developing Reliable AAV Standards for ELISA" and "The New AAV3 Titration ELISA" describing the establishment and characterization of AAV5 and AAV3 internal gold standards.

Yes, for AAV particle purification we recommend OptiPrep produced by Serumwerk Bernburg AG. You can find more information on our OptiPrep site.

Our Dip'n'Check AAV lateral flow assays are perfectly suitable to estimate the approximate titer quick and easy just before performing the PROGEN ELISA. The result within 20min will guide you to the optimal dilution for your sample to hit the dynamic range. More information about our Dip’n’Check can be found on our Poster: Potential Applications for AAV Lateral Flow Tests

PROGEN’s AAV ELISA kits are provided with one pre-coated microtiter plate containing 12 x 8-well-strips.

PROGEN recommends the use of seven serial dilutions of the provided Kit Control (standard curve), two blank controls and 2-3 dilutions of the unknown AAV samples to ensure a reliable quantification of AAV titers. The Kit Control and the AAV samples need to be tested in duplicates to provide accurate results (for further information take a look at the instructions provided with the AAV ELISA kit).

Bearing this in mind, once you have applied the standard curve, forty duplicate measurements can be applied.

Due to the high affinity and specificity of the AAV capture antibodies used for the PROGEN AAV ELISA kits, the detection of AAV particles from cell extracts is possible. However, detection is only possible within the reading range of the ELISA kits and reliable quantification depends on adequate titration of the corresponding samples. Furthermore, the detection of AAV capsids from cell extract can be influenced by several conditions, e.g. the composition of your lysis buffer. For example, high salt concentrations in your buffer might inhibit adequate capsid detection. We recommend to dilute the sample at least 1:10 in ASSB 1x to get a reliable result. For more information, see the following publication:

Grimm, D. et al. Titration of AAV-2 particles via a novel capsid ELISA: packaging of genomes can limit production of recombinant AAV-2. Gene Ther.6, 1322–30 (1999).

AAV Xpress ELISAs were developed based on the corresponding AAV Titration ELISAs.

The only difference is the adjustment of the kit components to shorten the assay time for the AAV Xpress ELISAs from ~4.5h to ~2h. The process is the same for both the AAV Xpress ELISAs and the AAV Titration ELISAs.

All the AAV Titration ELISAs and the AAV Xpress ELISAs have been calibrated based on the ATCC standard material (AAV2 & AAV8) or the PROGEN internal gold standard material (AAV1, AAV3, AAV5, AAV6, AAV9 & AAVrh10), respectively.
 
AAV shortprotocols

PROGEN offers AAV Titration ELISA kits for the quantification of AAV serotypes 1, 2, 3, 5, 6, 8, 9, and rh10 and AAV Xpress ELISA kits for AAV serotypes 2, 5, 6,  8, and 9. AAVrh74 capsids can be quantified with a combination of AAVrh10 ELISA and AAVrh74 kit control as standard, since the antibody used in the AAVrh10 ELISA also recognizes AAVrh74. 




AAV Standards FAQs

The empty capsids are prepared in the absence of an ITR plasmid containing the AAV vector genome, so that no viral vector DNA can be packaged in the particles. In some rare cases the preparations may contain a very small amount of capsids in which fragments of the host cell genome and the packaging plasmids or other DNA fragments have been packaged.

The total capsid titer of our empty capsids is determined by PROGEN ELISA. 

Analysis of the filling grade is performed by AUC or an orthogonal method such as UV/Vis. 

Empty capsids (AAV1, 2, 5, 6, 8, 9, rh10 and rh74) are provided in liquid format in PBS + 0.014% Tween20 + 1 mM MgCl2 + 2.5 mM KCl without protein additives. The titer is greater than 5.0E+12 capsids/ml. Therefore, they can be used in several applications.

ELISA Kit Controls (AAV1, 2, 3, 5, 6, 8, 9, rh10 and rh74) are lyophilized. After reconstitution in ASSB 1x the final solution contains stabilizing protein, phenol red and ASSB 1x buffer. The titer is lot-specific around 7.9E+09-1.3E+10 capsids/ml. This product is mainly suitable for the ELISA.




AAV Dip'n'Check FAQs

No, the Dip’n’Check assay detects all assembled capsids independent of filling grade.

The Dip’n’Check assay can be used with crude lysate. To find out more about the concentrations of tested tolerated buffer additives take a look in the product manual and go to Section 10 - Matrix Effects or you can also find Table 1 - Concentrations of tolerated buffer additives on the individual product website pages. 

The AAV Dip'n'Check test can be used for a variety of applications:

  1.  To compare AAV titers from different AAV preparations. With this information you can select the most promising sample for further processing. 
  2.  To estimate AAV titers in crude and purified AAV preparations. To either control efficiency of your processes or to pre-test AAV concentrations to hit the dynamic range of downstream analytics. 
  3.  To test the binding of common AAV antibodies to an AAV capsid variant. Allowing you to confirm which antibody-based methods are suitable for further analysis. 

More information about the determination of the Dip’n’Check can be found on our poster: Potential Applications for AAV Lateral Flow Tests

The lateral flow assay detects 1E+08 to 1E+10 total capsids in the assay volume, which corresponds to a concentration of 1E+09-1E+11 capsids/ml of the starting material.




AAV Antibodies FAQs

Yes, our AAV particle antibodies detect conformational epitopes only present on assembled capsids.

You can find all AAV particle antibodies here.

In contrast, AAV capsid protein antibodies recognize linear epitopes present on denatured VP proteins.

You can find all AAV capsid protein antibodies here.

Yes, PROGEN offers a selection of AAV antibodies in 10 µg sample sizes. You can find all available AAV antibodies here: AAV Antibodies

PROGEN offers a wide range of AAV antibodies in different quantities and formats (e.g. lyophilized and supernatant). A selection of AAV antibodies are also available in 10µg lyophilized sample sizes. For more information on the different AAV antibodies please see AAV Antibodies.

Anti-Adeno-Associated Virus Capsid Proteins Antibodies

For more information on the antibody binding epitopes of the capsid protein antibodies A1, B1 and A69 see the table below summarizing the published data from the following publication on the specific antibody binding sites:

Table Binding Sites of the AAV capsid protein antibodies

Wobus, C. E. et al. Monoclonal antibodies against the adeno-associated virus type 2 (AAV-2) capsid: epitope mapping and identification of capsid domains involved in AAV-2-cell interaction and neutralization of AAV-2 infection. J. Virol. 74, 9281–93 (2000).

Anti-Adeno-Associated Virus Particle Antibodies

For more information on the antibody binding epitopes on assembled AAV1, 2, 5, 8 and 9 capsids, see the tables below summarizing the published data from the following publications on the specific antibody binding sites:

summary binding epitopes


EM structures of assembled AAV1, 2, 4, 5, 6, and 8 capsids with Fab-fragments are available in the following publications: