In vitro, hematopoietic stem/progenitor cells can be isolated and cultured either in cytokine-supplemented medium or in co-culture with stromal cells that mimic the hematopoietic environment. By providing different combinations of growth factors and cytokines, the cells can be directed toward specific lineages. For example, IL-15 strongly supports NK-cell development, whereas Flt3L promotes DC development. ILCs can be generated from HSPCs/lymphoid progenitors using stromal-cell culture systems together with factors such as SCF, Flt3L and IL-7. After differentiation, the resulting populations can be identified by flow cytometry using cell-type-specific surface markers.