Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation

Figure 3

HLSCs inhibit NK activity. NKs, prestimulated for 24 hours with IL-15, were cocultured at the ratio of 5 : 1 with MSCs or HLSCs in direct contact or in transwells for 4 days. Subsequently, the NKs were challenged with a NK-susceptible target cell line (K562 cell line) and their degranulation was evaluated. (a) Representative () cytofluorimetric analysis of CD107a expression on NKs (NK CTRL) and on NKs after 4 hours of incubation with K562 cells (NK CTRL+K562). CD107a was detectable on NK membrane after incubation with K562 cells. (b) Representative () cytofluorimetric analysis of CD107a expression on NKs in the presence of K562 and after 4 days of incubation with MSCs or HLSCs. NKs cocultured with MSCs and HLSCs reduced their capacity to degranulate in the presence of specific target cells. (c)–(e) The death of K562 cells labelled with CFSE, which were evaluated by PI staining, after incubation for 4 hours with NKs stimulated with IL-15 (c) and cocultured, in the presence of transwells, for 4 days with MSCs (d) or with HLSCs (e).

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