Invited Speaker Presentation Eradicate Cancer 2020

DL4-mbeads Induce T Cell Differentiation from Stem Cells in a Stromal Cell-Free System (70264)

Ashton C Trotman-Grant 1 , Mahmood Mohtashami 1 , JC Zuniga-Pflucker 1 2
  1. Department of Immunology, University of Toronto and Sunnybrook Research Institute, Toronto, Canada
  2. University of Toronto, Toronto, ONTARIO, Canada

T cells are critical mediators of adaptive immunity and can be harnessed as therapeutic agents for regenerative medicine and for cancer immunotherapy. The generation of T cells, in vitro, from hematopoietic stem progenitor cells (HSPCs) offers the prospect of generating a renewable source of T cells. An unmet challenge in the field is the development of a clinically relevant system that could be easily scaled to generate large quantities of T-lineage cells. Here, we report a stromal cell-free, bead-based approach that supports the efficient in vitro development of both human progenitor T (proT) cells and mature T cells from CD34+ cells sourced from cord blood, GCSF-mobilized peripheral blood and PSC-derived hemogenic endothelium. Our strategy uses an artificial Notch signaling system, wherein Delta Like 4 is fused to immunoglobulin Fc domain (DL4-Fc) and immobilized to microbeads (DL4-μbeads). DL4-μbeads, along with the requisite cytokines, induced an ordered sequence of commitment and differentiation of CD34+ cells to CD34+CD7+ proT cells to CD3+abTCR T cells. Furthermore, the adoptive transfer of CD34+CD7+ proT cells demonstrated efficient engraftment in the thymus of NOD-SCID IL2rγnull (NSG) mice. DL4-μbeads provide a simple and robust platform to both study human T cell development and facilitate the development of engineered T cell therapies from renewable sources.