Fig. 1

Intrathymic injection of hematopoietic stem/progenitor cells induces a functional thymic microenvironment in NSG mice. a NSG recipients were intrathymically injected with 10,000 luciferase-expressing C57BL/6 LSK cells. The whole-body distribution of LSK-derived cells on day 15 after injection was monitored by in vivo BLI. Circles highlight the concentration of injected cells within the thymic area. Pseudocolor images superimposed on conventional photographs are shown. Four representative animals of ten are presented. b NSG recipients were intrathymically injected with 2000 C57BL/6 LSK cells. Thymuses were harvested 1 month after injection and analyzed for thymocyte subsets (DP, CD4 SP, CD8 SP, DN) (upper panel) and DN subsets (DN 1, 2, 3 and 4 subsets defined by expression of CD25 and CD44) (lower panel) by multicolor flow cytometry. Plots for one of three mice are presented. The thymus of an untreated NSG mouse was used as the control. c NSG mice were intrathymically injected with 10,000 luciferase-expressing C57BL/6 LSK cells. The thymus of an untreated NSG mouse was used as the control. Thymuses were harvested at day 60 and analyzed for cytokeratin (CK) 8 (red), CK 14 (green), and DAPI (blue) by immunofluorescence. Images were acquired with an Axio Imager (Zeiss) and processed with Zeiss ZEN imaging software. Scale bar 50 μm. One representative image is shown (n = 4). DP: CD4 and CD8 double-positive cells; DN: CD4 and CD8 double-negative cells; CD4 SP: CD4 single-positive cells; CD8 SP: CD8 single-positive cells