Environmental and developmental factors shape anti-AAV immunity in pigs

Area of Science:

• Immunology
• Gene Therapy
• Animal Models

Background:

• Pre-existing neutralizing antibodies against adeno-associated virus (AAV) vectors impede in vivo gene therapy efficacy.
• Current large-animal models like non-human primates are costly and limited in accessibility for studying anti-AAV immunity.

Purpose of the Study:

• To evaluate pigs as an immunologically relevant large-animal model for investigating humoral barriers to AAV-based gene therapy.
• To characterize the development and dynamics of anti-AAV immunoglobulin G (IgG) antibodies in pigs.

Main Methods:

• ELISA-based profiling across 11 AAV serotypes to detect anti-AAV IgG antibodies in pigs.
• Functional assays to assess the neutralizing capacity of pig antibodies against AAV particles.
• Analysis of capsid sequence to predict cross-reactive binding.

Main Results:

• Anti-AAV IgG antibodies were detected in pigs from two weeks of age, with titers increasing with age and showing serotype-specific patterns.
• Pigs housed in standard conditions exhibited greater inter-individual variation and broader serotype-specific antibody reactivities.
• Pig antibodies neutralized AAV particles in a dose- and serotype-dependent manner, and IgG depletion restored transduction.

Conclusions:

• Pigs represent a tunable large-animal model for studying age- and environment-dependent anti-AAV immunity.
• This model can recapitulate humoral barriers to AAV gene therapy and aid in evaluating immune evasion strategies.