Antigen-scaffolds drive preferential expansion of functional genetically engineered CAR and TCR T cells

Here, we expand CRISPR/Cas9- and lentiviral-engineered TCR T and CAR T cells. We expanded TCR T cells with Ag-scaffolds presenting peptide MHC (pMHC), and anti-CD19 CAR T cells with Ag-scaffolds presenting CD19 antigen. By applying cognate pMHC Ag-scaffolds, we achieved >80% antigen-specific T cells (83.62%±9.2%) after 14 days of culture with a distinct cytotoxic, proliferative phenotypical profile.

Ag-scaffold expansion enhanced initial TCR and CAR cytotoxicity; sustained control was observed after repeated rechallenges of CAR T cells. In vivo, Ag-scaffold-expanded CRISPR/Cas9-engineered anti-CD19 CAR T also showed complete tumour eradication in a B-cell lymphoma xenograft model with a low dose of CAR T cells, which was not achieved using IL2/7/15 expansion.