Generation of functional natural killer T cell subsets from human bone marrow derived adult hematopoietic stem progenitor cells (P4456)

Abstract

Abstract Natural killer T (NKT) cells constitute an important subset of T cells that can both directly and indirectly mediate anti-tumor immunity. However, cancer patients have a reduction in both NKT cell number and function, and these deficits limit the potential clinical application of NKT cells for cancer therapy. To overcome the problem of limited NKT cell numbers, we have investigated whether NKT cells can be generated in vitro from bone marrow-derived adult hematopoietic stem-progenitor cells (HSPC).Our data demonstrate that co-culture of human bone marrow HSPC with OP9 stromal cells transduced with Notch ligand delta-like 1 (OP9-DL1), generates a CD3+ T cell population. These CD3+ precursors can be further differentiated into CD8- NKT cells by secondary culture with CD1d-Ig based artificial antigen presenting cells (aAPC), expressing anti-CD28mAb and loaded with α-GalCer. Importantly, these in vitro-generated NKT cells are functional as demonstrated by their ability to proliferate and secrete IFN-γ following stimulation. These findings demonstrated for the first time that functional human NKT cells can be effectively generated from HSPC in the absence of genetic manipulation or viral transduction. These studies will serve to help understand and design NKT cell-based approaches to enhance current immunotherapeutic strategies for cancer.