Boardman and Mangat et al. asked if engineering CAR Treg cells to enhance a suppressive mechanism (IL-10) and simultaneously remove an inhibitory signal (PD-1) would improve their suppressive function. CRISPR-mediated PD-1 deletion increased CAR Treg cell activation, while knock-in of IL-10 into the PDCD1 locus of HLA-A2-specific CAR Tregs (IL-10KITreg), resulted in high levels of antigen-dependent, CAR-regulated IL-10 secretion. IL-10KITreg cells demonstrated increased suppression of dendritic cells and allo-antigen- and islet auto-antigen-specific T cells. In vivo, IL-10KITreg cells were safe, stable, secreted IL-10, and suppressed DCs and xenogeneic GvHD.
Contributed by Katherine Turner
ABSTRACT: Regulatory T cell (T(reg) cell) therapy has been transformed through the use of chimeric antigen receptors (CARs). We previously found that human T(reg) cells minimally produce IL-10 and have a limited capacity to control innate immunity compared to type 1 regulatory T cells (T(r)1 cells). To create "hybrid" CAR T(reg) cells with T(r)1 cell-like properties, we examined whether the PDCD1 locus could be exploited to endow T(reg) cells with CAR-regulated IL-10 expression. CRISPR-mediated PD1 deletion increased CAR T(reg) cell activation, and knock-in of IL10 under control of the PD1 promoter resulted in CAR-induced IL-10 secretion. IL10 knock-in improved CAR T(reg) cell function, as determined by increased suppression of dendritic cells and alloantigen- and islet autoantigen-specific T cells. In vivo, IL10 knock-in CAR T(reg) cells were stable, safe, and suppressed dendritic cells and xenogeneic graft-versus-host disease. CRISPR-mediated engineering to simultaneously remove an inhibitory signal and enhance a suppressive mechanism is a previously unexplored approach to improve CAR T(reg) cell potency.
Author Info: (1) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (2) Department of Surgery, T
Author Info: (1) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (2) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada. (3) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (4) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (5) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (6) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (7) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (8) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (9) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (10) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (11) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (12) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. (13) Department of Pathology, Stanford University, Stanford, CA, USA. (14) Department of Surgery, The University of British Columbia, Vancouver, BC, Canada. BC Children's Hospital Research Institute, Vancouver, BC, Canada. School of Biomedical Engineering, The University of British Columbia, Vancouver, BC, Canada.
