Potent expansion of human natural killer T cells using alpha-galactosylceramide (KRN7000)-loaded monocyte-derived dendritic cells, cultured in the presence of IL-7 and IL-15

Natural killer T (NKT) cells have an extremely restricted T-cell receptor r epertoire, in man consisting of a V alpha 24 chain preferentially paired wi th a V beta 11 chain. and play crucial roles in various immune responses. C haracterization of circulating V alpha 24(+)V beta 11(+)-T cells is hampere d by their low frequencies. The alpha -galactasylceramide KRN7000 was repor ted to be presented by CD1d to NKT cells. Since dendritic cells (DC) are po tent antigen presenting cells, and have been shown to express CD1d, we anal yzed whether these cells could efficiently mediate expansion of V alpha 24( +)V beta 11(+)-T cells. During a 7-day co-culture of peripheral blood monon uclear cells and KRN7000-loaded mature monocyte derived DC (moDC) in the pr esence of interleukin-7 (IL-7) and IL-15, we observed up to 76-fold expansi on of V alpha 24(+)V beta 11(+)-T cells. The expanded V alpha 24(+)V beta 1 1(+)-T cells expressed the cytotoxic molecule granzyme B, showed negligible expression of Fas ligand and could be induced to express high levels of In terferon-gamma. while retaining the capacity to produce IL-4. B cells, expr essing CD1d. could also present KRN7000, but V alpha 24(-)V beta 11(+)-T ce ll expansion was only observed in the presence of IL-7 and/or IL-15. Consid ering the low frequency of circulating V alpha 24(+)V beta 11(+)-T cells. t he present method for expansion of V alpha 24(+)V beta 11(+)-T cells using KRN7000-loaded mature moDC will be of value for the further characterizatio n of this unique T cell subset. (C) 2001 Elsevier Science B.V. All rights r eserved.