T-lineage committed cells were isolated from human cord blood hematopoietic progenitor cells, transduced with either a CAR or TCRα/β construct, and expanded. The transduced cells had a mostly naive phenotype and were functional and, importantly, lacked surface-expressed endogenous CD3/TCRα/β complexes, reducing the potential for alloreactivity.
Recent clinical studies indicate that adoptive T-cell therapy and especially chimeric antigen receptor (CAR) T-cell therapy is a very potent and potentially curative treatment for B-lineage hematologic malignancies. Currently, autologous peripheral blood T cells are used for adoptive T-cell therapy. Adoptive T cells derived from healthy allogeneic donors may have several advantages; however, the expected occurrence of graft versus host disease (GvHD) as a consequence of the diverse allogeneic T-cell receptor (TCR) repertoire expressed by these cells compromises this approach. Here, we generated T cells from cord blood hematopoietic progenitor cells (HPCs) that were transduced to express an antigen receptor (AR): either a CAR or a TCR with or without built-in CD28 co-stimulatory domains. These AR-transgenic HPCs were culture-expanded on an OP9-DL1 feeder layer and subsequently differentiated to CD5+CD7+ T-lineage precursors, to CD4+ CD8+ double positive cells and finally to mature AR+ T cells. The AR+ T cells were largely naive CD45RA+CD62L+ T cells. These T cells had mostly germline TCRalpha and TCRbeta loci and therefore lacked surface-expressed CD3/TCRalphabeta complexes. The CD3- AR-transgenic cells were mono-specific, functional T cells as they displayed specific cytotoxic activity. Cytokine production, including IL-2, was prominent in those cells bearing ARs with built-in CD28 domains. Data sustain the concept that cord blood HPC derived, in vitro generated allogeneic CD3- AR+ T cells can be used to more effectively eliminate malignant cells, while at the same time limiting the occurrence of GvHD.