Immature human DCs in tissues of NOD/SCID mice engrafted with human CD34⁺ HPC. Immunofluorescence and confocal analysis of frozen tissue sections from skin (A; 3 of 3 tested mice) and lung (B; 6 of 6 tested mice) of NOD/SCID mice engrafted with human CD34⁺ HPC. (A) Staining with anti–human CD11c-FITC (green), anti–human Langerin-TxR (CD207, red) and anti–human HLA-DRCy5 (blue). Single fluorescence and overlay (no. 4 from experiment 1 in Table 1, which received a transplant of 3 × 10⁵ cord blood CD34⁺ HPCs). Note the colocalization of Langerin and HLA-DR in cytoplasmic compartments consistent with immature DC phenotype in the skin (× 63 magnification with zoom of × 2. (B) Anti–human HLA-DR-FITC and 7AAD nuclei staining in the lung (projection × 40 magnification and section at zoom × 2). Note intracellular localization of anti–HLA-DR staining. HLA-DR staining was either direct with FITC-conjugated mAb or indirect with streptavidin and is representative of tested samples of lung harvested from 10 different engrafted mice. Note the large infiltration of human cells in the lung as well as dendritic morphology of HLA-DR⁺ cells.