The in vivo effects of IL-7 on TREC generation in NOD-SCID-hu mice.

Four weeks after implantation of human fetal thymus and liver, NOD-SCID-hu mice were treated with 100 ng IL-7 twice daily for 10 days. Seven (control, n = 3; IL-7, n = 4) and 21 days (control, n = 5; IL-7, n = 7) after the last injection, the grafts, spleen, and PBMCs were recovered from the mice for phenotypic analysis and TRECs. The upper panels of panel A indicate percentage of human CD3⁺cells and the panels in the middle row of panel A indicate human CD4⁺ and CD8⁺ expression on the CD3⁺ population of PBMC (left) and spleen (right). The bottom figures of panel A show CD45RA⁺ cells on CD3⁺CD4⁺ or CD3⁺CD8⁺populations of PBMCs (left) and spleen (right). The TREC levels of grafts and the graft weights in control and IL-7–treated mice are shown in panels B and C, respectively. The percentages of Ki67⁺ cells in each subpopulation of grafts are shown in panel D.