Antigen-specific In Vitro Expansion of Functional Redirected NY-ESO-1-specific Human CD8⁺ T-Cells in a Cell-free System

Abstract

Background: Tumors can be targeted by the adoptive transfer of chimeric antigen receptor (CAR) redirected T-cells. Antigen-specific expansion protocols are needed to generate large quantities of redirected T-cells. We aimed to establish a protocol to expand functional active NY-ESO-1-specific redirected human CD8⁺ T-cells. Materials and Methods: The anti-idiotypic Fab antibody A4 with specificity for HLA-A*0201/NY-ESO-1_157-165 was tested by competition assays using a HLA-A*0201/NY-ESO-1_157-165 tetramer. HLA-A*0201/NY-ESO-1_157-165 redirected T-cells were generated, expanded and tested for CAR expression, cytokine release, in vitro cytolysis and protection against xenografted HLA-A*0201/NY-ESO-1_157-165–positive multiple myeloma cells. Results: A4 demonstrated antigen-specific binding to HLA-A*0201/NY-ESO-1_157-165 redirected T-cells. Expansion with A4 resulted in 98% of HLA-A*0201/NY-ESO-1_157-165 redirected T-cells. A4 induced strong proliferation, resulting in a 300-fold increase of redirected T-cells. After expansion protocols, redirected T-cells secreted Interleukin-2, (IL-2), interferon gamma (IFNγ) and tumor necrosis factor alpha (TNFα) and lysed target cells in vitro and were protective in vivo. Conclusion: A4 expanded HLA-A*0201/NY-ESO-1_157-165 redirected T-cells with preservation of antigen-specific function.