Progenitor T-cell differentiation from hematopoietic stem cells using Delta-like-4 and VCAM-1

The molecular and cellular signals that guide T-cell development from hematopoietic stem and progenitor cells (HSPCs) remain poorly understood. The thymic microenvironment integrates multiple niche molecules to potentiate T-cell development in vivo. Recapitulating these signals in vitro in a stromal cell-free system has been challenging and limits T-cell generation technologies. Here, we describe a fully defined engineered in vitro niche capable of guiding T-lineage development from HSPCs. Synergistic interactions between Notch ligand Delta-like 4 and vascular cell adhesion molecule 1 (VCAM-1) were leveraged to enhance Notch signaling and progenitor T-cell differentiation rates. The engineered thymus-like niche enables in vitro production of mouse Sca-1⁺cKit⁺ and human CD34⁺ HSPC-derived CD7⁺ progenitor T-cells capable of in vivo thymus colonization and maturation into cytokine-producing CD3⁺ T-cells. This engineered thymic-like niche provides a platform for in vitro analysis of human T-cell development as well as clinical-scale cell production for future development of immunotherapeutic applications.