Tetramer-Based Enrichment of Preexisting Anti-AAV8 CD8+ T Cells in Human Donors Allows the Detection of a TEMRA Subpopulation

Front Immunol. 2020 Jan 21:10:3110. doi: 10.3389/fimmu.2019.03110. eCollection 2019.


Pre-existing immunity to AAV capsid may compromise the safety and efficiency of rAAV-mediated gene transfer in patients. Anti-capsid cytotoxic immune responses have proven to be a challenge to characterize because of the scarcity of circulating AAV-specific CD8+ T lymphocytes which can seldom be detected with conventional flow cytometry or ELISpot assays. Here, we used fluorescent MHC class I tetramers combined with magnetic enrichment to detect and phenotype AAV8-specific CD8+ T cells in human PBMCs without prior amplification. We showed that all healthy individuals tested carried a pool of AAV8-specific CD8+ T cells with a CD45RA+ CCR7- terminally-differentiated effector memory cell (TEMRA) fraction. Ex vivo frequencies of total AAV-specific CD8+ T cells were not predictive of IFNγ ELISpot responses but interestingly we evidenced a correlation between the proportion of TEMRA cells and IFNγ ELISpot positive responses. TEMRA cells may then play a role in recombinant AAV-mediated cytotoxicity in patients with preexisting immunity. Overall, our results encourage the development of new methods combining increased detection sensitivity of AAV-specific T cells and their poly-functional assessment to better characterize and monitor AAV capsid-specific cellular immune responses in the perspective of rAAV-mediated clinical trials.

Keywords: AAV; CD8+ T lymphocytes; gene therapy; immune response; tetramer-associated magnetic enrichment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • CD8-Positive T-Lymphocytes / immunology*
  • Capsid Proteins / genetics
  • Capsid Proteins / immunology
  • Dependovirus / genetics
  • Dependovirus / immunology*
  • Female
  • Genetic Therapy / instrumentation
  • Genetic Vectors / genetics
  • Genetic Vectors / immunology*
  • Humans
  • Immunologic Memory
  • Interferon-gamma / genetics
  • Interferon-gamma / immunology
  • Male
  • Middle Aged
  • Receptors, CCR7 / genetics
  • Receptors, CCR7 / immunology
  • Young Adult


  • CCR7 protein, human
  • Capsid Proteins
  • Receptors, CCR7
  • Interferon-gamma