Increased expansion of V alpha 24+ T cells derived from G-CSF-mobilized peripheral blood stem cells as compared to peripheral blood mononuclear cells following alpha-galactosylceramide stimulation.

In the present study, unpurified peripheral blood mononuclear cells (PBMCs) from various sources, including steady-state blood (normal donors) and granulocyte colony-stimulating factor (G-CSF)-mobilized blood (cancer patients and normal donors) (G-PBSC), were cultured in RPMI-1640 in the presence of IL-2 and alpha-galactosylceramide (alpha-GalCer) to expand V alpha 24(+) T cells, and their expansion kinetics were compared. G-CSF-mobilized cells showed markedly higher expansion potential (350-fold expansion of V alpha 24(+) T cells, regardless of whether the cells were from cancer patients or normal donors) than steady-state cells (15-fold expansion, compared to the initial inoculums) (n = 5, P < 0.01). We also confirmed that the CD14(-) fraction of G-PBSCs contained a large number of precursors of V alpha 24(+) T cells, compared to PBSCs, as well as a large number of CD14(+) cells, which assist V alpha 24(+) T cell proliferation. Our simple and practical procedure, which eliminates complicated cell manipulation (including cell purification), produces efficient expansion of V alpha 24(+) T cells when G-CSF-mobilized blood cells are cultured with alpha-GalCer.