Strategies for Evading Cellular Immunity Against Recombinant AAV Vectors in Gene Therapy

Area of Science:

• Gene Therapy
• Immunology
• Virology

Background:

• Adeno-associated virus (AAV) vectors are widely used for in vivo gene transfer due to their safety and tissue tropism.
• Despite numerous approvals, pre-existing anti-AAV neutralizing antibodies (NAbs) and T cell responses pose significant challenges to long-term gene therapy efficacy.
• Cellular immunity, particularly cytotoxic T lymphocytes (CTLs) targeting transduced cells, is a major hurdle for recombinant AAV (rAAV) gene therapy.

Purpose of the Study:

• To review strategies for evading anti-rAAV cellular immunity.
• To discuss the advantages and limitations of these strategies within the context of rAAV transduction and immune response mechanisms.
• To highlight current challenges and emerging technologies in rAAV gene therapy immunogenicity.

Main Methods:

• Literature review of studies on AAV vector immunogenicity.
• Analysis of cellular immune responses (T cells, CTLs) to AAV capsids.
• Evaluation of strategies to mitigate anti-AAV immune responses.

Main Results:

• Pre-existing immunity, including neutralizing antibodies and T cell responses, is prevalent in the population.
• CTL responses against transduced cells are a key factor limiting the durability of rAAV gene therapy.
• Various strategies exist to circumvent cellular immunity, each with specific benefits and drawbacks.

Conclusions:

• Overcoming anti-rAAV cellular immunity is crucial for advancing the long-term effectiveness of gene therapies.
• Understanding the interplay between rAAV vectors and the immune system is essential for developing next-generation therapies.
• Emerging technologies hold promise for addressing the immunogenicity challenges in AAV-based gene therapy.