Genome packaging efficiency using native mass spectrometry to characterize AAV capsids

[Aaron_TFS]

Knowing the genome packaging efficiency during adeno-associated virus (AAV) manufacturing is a crucial step toward the successful clinical application of next-generation biotherapeutics.

In recent years, recombinant AAV production has been steadily optimized to yield high genome packaging efficiency; but empty capsids often remain an undesired byproduct during manufacturing. Additionally, some evidence shows immune reactions caused by empty capsids. Therefore, it’s important to know the precise amount of correctly filled AAV capsids in order to determine the correct dosage required for treatment.

For all these reasons, it’s extremely important to have analytical methods in place to quantitatively evaluate capsid species present during downstream processing.

However, choosing the right technique can be challenging. While the most common techniques are analytical ultracentrifugation (AUC), anion-exchange chromatography (AEX) and capillary electrophoresis, those methods rely on absorbance-based detection, which can be problematic. There’s no reason to not consider native mass spectrometry (MS) to achieve the goal.

Strategy: Use native MS to characterize AAV capsids for genome packaging efficiency

In a recent experiment, Thermo Fisher Scientific demonstrated how native MS analysis of AAV capsids allows for accurate assessment of genome packaging efficiency. The study showed how native MS can be used to successfully quantify full and empty AAV capsids.

Conclusions of the study

• The team demonstrated the potential of using the Thermo Scientific™ Q Exactive™ UHMR (ultra-high mass range) hybrid-quadrupole-Orbitrap™ mass spectrometer for the intact native MS analysis of viral capsids.
• The method can be applied to various AAV serotypes and has great utility for application during downstream processing.
• Intact native mass spectrometry for the analysis of AAV-based viral vectors does not require laborious sample preparation, thus minimizing potential sample loss.
• Short acquisition times enable rapid determination of the empty: full capsid ratio.

Read more details in this customer note.