Direct comparison of target-reactivity and cross-reactivity induced by CAR- and BiTE-redirected T cells for the development of antibody-based T-cell therapy

The development of chimeric antigen receptor (CAR) and bispecific T-cell engager (BiTE) has led to the successful application of cancer immunotherapy. The potential reactivity mediated by CAR- and BiTE-redirected T cells needs to be assessed to facilitate the application of these treatment options to a broader range of patients. Here, we have generated CAR and BiTE possessing the same single chain fragment variable (scFv) specific for the HLA-A2/NY-ESO-1(157-165 )complex (A2/NY-ESO-1(157)). Using HLA-A2(+)NY-ESO-1(+) myeloma cells and peptides presented by HLA-A2 molecules as a model, both sets of redirected T cells recognized and killed HLA-A2(+)NY-ESO-1(+) myeloma cells in an A2/NY-ESO-1(157)-specific manner in vitro. Moreover, CAR- and BiTE-activated T cells showed similar functional avidity, as assessed by cytokine production and killing activity, both displaying antitumor reactivity against HLA-A2(+)NY-ESO-1(+) myeloma cells in vivo. Interestingly, cross-reactivity for homologous peptides presented by HLA-A*02:01 and NY-ESO-1(157) peptide presented by HLA-A2 alleles was not identical between CAR-and BiTE-redirectedT cells, probably due to structural differences of modified antibodies. These results have demonstrated that both antitumor CAR- and BiTE-activated T cells have comparable potential to recognize tumors, while paying attention to unknown off-target reactivity that would differ for each antibody-based modality even if the same scFv was employed.