ILC3s in pediatric tonsils and spleens of huNSG mice. (A) Sorting strategy for isolation of viable (Aqua Live/Dead−) human (huCD45⁺) ILCs: after exclusion of cells positive for CD3, CD19, CD14, CD16, FcεRIα, CD34, TCRα/β, TCRγ/δ, and CD294, ILC3s were identified as CD127⁺CD117⁺ and selected for NKp44⁺ (red) or NKp44⁻NKp46⁻ (dark blue, referred to as NCR⁻). NK cells were sorted as NKp46⁺CD127⁻CD94⁺ cells (yellow). Shown is a representative spleen sample, magnetic-activated cell sorting (MACS)–depleted for CD19, CD14, CD4, and CD8. (B) Pie charts show mean frequency (±SD) of the indicated populations among ILCs of interest, as defined in panel A, within spleen (N = 26 from 20 human fetal liver [HFL] donors with 2 to 15 mice per donor), small intestine (SI) (N = 12 from 9 HFL donors with 4-15 pooled mice), and pediatric tonsils (N = 16). (C) Mean frequency (±SD) of the indicated populations among huCD45⁺ cells derived from spleen (N = 3, 1-8 mice per HFL donor) and SI (samples as in panel B). FSC-A, forward scatter area; FSC-H, forward scatter height; SSC-A, side scatter area; TCR, T-cell receptor.