Human thymic epithelial cell (TEC) culture system for promoting T lineage commitment and development of T cells from cord blood and bone marrow stem cells (86.6)

The discovery of Delta-like-1 (Dl1)/Notch signaling as the earliest requirement for T lineage commitment and development makes it possible to generate T cells from hematopoietic stem cells in vitro. The mouse bone marrow stroma OP9 cells that overexpress Dl1is the first stroma cell line that is capable of promoting the development of both mouse and human T cells; however, a similar approach with human stroma cells has not been established. To develop a similar culture system to closely emulate human T cell development, we have generated a human TEC line from a pediatric thymus and expressed the mouse Dl1 in this line (TEC84-Dl1). The TEC84-Dl1 expresses CD104, CD29, CD49f, CD54 (ICAM-1), and CD106 (VCAM-1); these cells also express HLA-ABC and HLA-DR. When TEC84-Dl1 were co-cultured with cord blood CD34posCD45RAposCD38neg cells, we were able to generate preT/NK (CD34posCD7posCD1aneg), preT (CD34posCD7posCD1apos), immature single positive and double positive subsets; the co-culture system also generated a CD3pos subset. Similar results were also obtained with CD34pos cells isolated from adult bone marrow. Thus, our co-culture system with the human TEC provides a complete human system for replicating thymopoiesis in vitro and offers a novel tool to optimize the development of T lineage cells that would benefit cord blood and bone marrow transplant recipients (Supports: AG023809 to PL, IDPH to PS, AI068390 to KK).