January 30, 2024

Optimizing AAV Gene Therapy: Overcoming Immune Barriers for Enhanced Safety and Efficacy

In the rapidly expanding field of gene therapy, ensuring safety and efficacy remains a primary challenge. Neutralizing antibodies (NAb) against adeno-associated virus (AAV) capsids can impede the success of treatments. 

This blog post explores strategies to overcome NAb challenges and introduces the iLite® AAV NAb platform for precise NAb measurement across different AAV serotypes in human and non-human primate (NHP) serum samples.

January 30, 2024

Optimizing AAV Gene Therapy: Overcoming Immune Barriers for Enhanced Safety and Efficacy

In the rapidly expanding field of gene therapy, ensuring safety and efficacy remains a primary challenge. Neutralizing antibodies (NAb) against adeno-associated virus (AAV) capsids can impede the success of treatments. 

This blog post explores strategies to overcome NAb challenges and introduces the iLite® AAV NAb platform for precise NAb measurement across different AAV serotypes in human and non-human primate (NHP) serum samples.

Neutralizing Antibodies: Key Immune Barriers

Clinical promise aside, AAV capsids face challenges due to pre-existing NAb from individuals with prior exposure to wild-type AAV. These antibodies bind to viral capsids, impacting AAV-mediated gene transfer and diminishing gene therapy efficacy. 
Addressing the presence of NAb during the development of AAV-based therapy, it is crucial to develop strategies to overcome capsid immunity.  Strategies like epitope masking, directed evolution, plasmapheresis, IgG-degrading enzymes, and structural modifications have been developed to address capsid immunity.

 

        Strategies to overcome capsid immunity: 

  • Epitope Masking: Coating the AAV surface with lipids or extracellular vesicles to mask NAb recognition sites.
  • Directed Evolution: Identifying AAV variants less sensitive to NAbs through mutational screening.
  • Plasmapheresis: Removing antibodies from the blood to minimize vector-NAb contact.
  • IgG-degrading Enzymes: Temporarily eliminating IgG for a NAb-free window.
  • Structural Modifications: Modifying NAb recognition sites without affecting production efficiency

 

 

Challenges of Accurate NAb Measurement

Accurate NAb measurement with the current AAV-luciferase gold standard method faces challenges due to various factors, including high variability in AAV production from one batch to another, complex incubation procedures that can lead to assay variations, the presence of empty capsids, and matrix effects that can falsely lower the NAb assay results and create false positives. 

Therefore, it is essential to have reproducible and specific in vitro assays for each AAV variant or serotype.

Furthermore, cell-based assays are crucial since they provide a direct and accurate evaluation of neutralization activity for each AAV serotype or variant. 

 

Assessing AAV NAbs with a Robust Platform

Introducing the iLite® AAV NAb platform which offers a robust solution to address the challenges in current NAb assessment methods. The platform offers several benefits, including: 

  • Reliability: The proven iLite technology ensures consistent results across multiple AAV capsid serotypes.
  • Accuracy: The platform provides a semi-quantitative assay for rapid and accurate NAb detection. 
  • Reproducibility: The assay-ready AAV packaging and responsive cell format guarantee consistent cell numbers collected and frozen at the same passage in each vial. 
  • Flexibility: Customizable packaging of AAV serotype-producing cells for any serotype and its derivates to cater to diverse research needs. 

 

Customized Solutions for Diverse Gene Therapy Needs

The iLite AAV NAb platform, a two-component system, can be tailored to accommodate various immunogenicity projects.
With a flexible AAV packing cell setup, it's possible to produce any type of vector, including hybrid, chimeric, or semi-synthetic capsids. 

This platform can help optimize your AAV vector to overcome challenges and enhance the safety and efficacy of AAV gene therapy.  

Get the advantage of our expertise - contact us today and discuss your AAV vector needs!

 

References:

Muhuri M, Maeda Y,et al. Overcoming innate immune barriers that impede AAV gene therapy vectors. J Clin Invest. 2021