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Tetramer-Based Enrichment of Preexisting Anti-AAV8 CD8 + T Cells in Human Donors Allows the Detection of a T EMRA Subpopulation
Abstract : 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 (T EMRA) 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 T EMRA cells and IFNγ ELISpot positive responses. T EMRA 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.
Cited literature [61 references]
https://www.hal.inserm.fr/inserm-02447186
Contributor : Nicolas Jaulin <>
Submitted on : Tuesday, January 21, 2020 - 2:31:33 PM
Last modification on : Thursday, January 23, 2020 - 1:39:53 AM
Contributor : Nicolas Jaulin <>
Submitted on : Tuesday, January 21, 2020 - 2:31:33 PM
Last modification on : Thursday, January 23, 2020 - 1:39:53 AM
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2020 Xicluna.pdf
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