Fig. 9: Detection of TE-DCs in human thymi.

a and b Representative confocal micrographs of five human thymus grafts from humanized BLT mice show the close association of human hCD11c⁺ DCs (green) with hCD31⁺ human, vascular endothelium (white, arrows), and nuclear DAPI staining (blue). The scale bar represents 10 μm. b Higher magnification images show a hCD11c⁺ human DC that breaches the endothelial barrier (arrowhead). The upper panel shows hCD11c⁺ DCs (green) and hCD31⁺ human, vascular endothelium (white), the lower displays a surface rendered illustration of hCD11c⁺ DCs. The scale bar represents 10 μm. c Humanized BLT mice were injected IV with anti-human hCD11c-PE or isotype-PE mAb, euthanized 2 mins later and PE⁺ DCs from the animals’ grafted human thymus, endogenous spleen, and blood were analyzed by flow cytometry. Each symbol represents an individual animal; open symbols indicate isotype-PE injected mice, closed symbols are anti-human CD11c-PE injected mice. n = 5 mice/group for isotype-PE i.v., n = 6 for CD11c-PE i.v. thymi and n = 7 for CD11c-PE i.v. spleen and blood each (two-way ANOVA). d Uptake of Alexa 488 labeled ovalbumin (Ova-AF488) by human DCs in BLT mice. In all, 5 min after IV injection of 100 μg Ova-AF488, single-cell suspensions of the human thymus, mouse spleen, and blood were obtained and stained for hCD11c⁺ DC. n = 5 mice/group except for n = 4 for Ova-AF488 i.v. spleen (two-way ANOVA). Bars and error bars represent mean ± SEM. *P = 0.0234; **P = 0.003; ****P < 0.0001; n.s.: not significant.