Antigen receptor-redirected T cells derived from hematopoietic precursor cells lack expression of the endogenous TCR/CD3 receptor and exhibit specific antitumor capacities

Abstract

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 TCRα and TCRβ loci and therefore lacked surface-expressed CD3/TCRαβ 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.

The human fetal thymus generates invariant effector γδ T cells

“…HTS of the generated amplicon products containing the CDR3γ or CDR3δ sequences was performed on an Illumina MiSeq platform using the V2 300 kit, with 151 bp at the 3′ end (read 2) and 151 bp at the 5′ end (read 1; at the GIGA Center, University of Liège, Belgium). HTS analysis of TRA and TRB loci was performed as previously described (Van Caeneghem et al, 2017).…”

Chimeric antigen receptor–induced BCL11B suppression propagates NK-like cell development

“…A growing body of evidence suggests that the introduction of either a TCR or a CAR into human hematopoietic progenitor cells can prevent endogenous rearrangement of the TCR-α and TCR-β locus, thereby giving rise to monospecific T cells that express the transgenic antigen receptor only (12,33,34). We demonstrated that, as in the murine model, early signals mediated by a CAR that had been transduced into CD34 + hematopoietic human stem cells result in decreased expression of NOTCH1, which leads to a suppression or regular progenitor T cell development in favor of NK-like cell differentiation.…”

“…UCB-derived lymphoid progenitor cells (termed proT2) being CD34 + CD7 + CD5 + have been identified as a potential equivalent of the in vitro-generated murine DN2 precursor T cell population (13,38). We and others have shown that UCB-derived lymphoid progenitors can be genetically engineered (12,14). Our data on TCR rearrangement and gene expression in both murine and human systems support earlier studies showing that human and murine lymphoid development are much more similar than originally reported (30) and encourage its further exploitation for clinical use.…”

“…Here, in order to circumvent the limitation of TCR restriction, we used CAR-engineered hematopoietic progenitor cells to generate lymphoid precursors in vitro using the Notch-based OP9-DL1 culture system. Elegant proof-of-principle studies suggested the relevance of this concept for humans; however, exploration in vivo remains complex (12)(13)(14). Using a murine and human CD19 CAR (15), we targeted a clinically relevant antigen and were able to assess its immunological impact on lymphoid progenitor development and demonstrate strong evidence for its translational relevance for humans.…”

AllogeneicCD27‐depleted cells in adoptive cell therapy

“…Other approaches to reduce GVHD potential in allogeneic products require additional genetic modifications, adding both complexity and cost. Such approaches include knocking out (or down) the endogenous TCR, targeting integration of CAR into the TCR locus, or using CD3 neg cells such as those derived from hematopoietic precursor cells . A potential issue with these approaches is that CD3ζ ‐containing CAR requires its dimerization and interaction with an endogenous TCR/CD3 complex for optimal function .…”