IL15 and neoplasm: Although CD56bright CD16– and CD56dim CD16+ NK cell subsets develop in NSG and SRG mice [14], functional NK cells that mediate antibody-dependent cellular cytotoxicity (ADCC), lyse HLA class I negative tumor cells or produce interferon gamma (IFN-γ) upon infection have only been observed in humanized mice that express human IL-2 (NOG-IL2 [156]), human IL-15 (SRG-15 [14], NOG-IL15 [42], NSG-IL15 [41], NSG-IL7-IL15 [40]) or in MISTRG mice, where functional IL-15-expressing human macrophages develop [18].