Figure 7.

Skin-cell explants cannot maintain T-lineage committed cells. HSC from indicated donors were pre-differentiated on monolayers of thymic stromal cells expressing huDLL-1 (see figure 2). After 4 weeks, 55-65% of the cells were CD5⁺CD7⁺ (see insert UL), and > 90% iCD3⁺CD45RA⁺ (NS). 1 × 10⁵ cells were seeded in skin-cell explants and cultured for 2 and 4 weeks. In the presence of IL15, the population expanded 10-15 ×. Already at 2 weeks, all cells had lost expression of CD5 and become CD56⁺ NK-lineage committed cells. The same phenotype was observed when IL-15 was omitted, although overall expansion was strongly reduced to 1-1,5 ×.