Generation of Functional Antigen-Specific CD8+ Human T Cells from Cord-Blood Stem Cells using Exogenous Notch and Tetramer-TcR Signaling

摘要

In vitro differentiation of mouse and human stem cells into early T cells has been successfully demonstrated using artificial Notch signaling systems. However, generation of mature, antigen-specific, functional T cells, directly from human stem cells has remained elusive, except when using stromal co-culture of stem cells retrovirally transfected with antigen-specific T cell receptors (TCRs). Here we show that human umbilical cord blood (UCB)-derived CD34+CD38−/low hematopoietic stem cells (HSCs) can be successfully differentiated into functional, antigen-specific cytotoxic CD8+ T cells without direct stromal co-culture or retroviral TCR transfection. Surface-immobilized Notch ligands (DLL1) and stromal cell conditioned medium successfully induced the development of CD1a+CD7+ and CD4+CD8+ early T cells. These cells, upon continued culture with cytomegalovirus (CMV) or Influenza-A virus epitope-loaded HLA-A*0201 tetramers, resulted in the generation of a polyclonal population of CMV-specific or Influenza-specific CD8+ T cells respectively. Upon further activation with antigen-loaded target cells, these antigen-specific, stem cell-derived T cells exhibited cytolytic functionality, specifically CD107a surface mobilization, IFNγ production, and Granzyme B secretion. Such scalable, in vitro generation of functional, antigen-specific human T cells from human stem cells could eventually provide a readily available cell source for adoptive transfer immunotherapies and also allow better understanding of human T cell development.