Hepatocytes and IL-15: a favorable microenvironment for T cell survival and CD8+ T cell differentiation.


Human intrahepatic lymphocytes are enriched in CD1d-unrestricted T cells coexpressing NKR. Although the origin of this population remains controversial, it is possible to speculate that the hepatic microenvironment, namely epithelial cells or the cytokine milieu, may play a role in its shaping. IL-15 is constitutively expressed in the liver and has a key role in activation and survival of innate and tissue-associated immune cells. In this in vitro study, we examined whether hepatocyte cell lines and/or IL-15 could play a role in the generation of NK-like T cells. The results show that both HepG2 cells and a human immortalized hepatocyte cell line increase survival and drive basal proliferation of T cells. In addition, IL-15 was capable of inducing Ag-independent up-regulation of NKR, including NKG2A, Ig-like receptors, and de novo expression of CD56 and NKp46 in CD8(+)CD56(-) T cells. In conclusion, our study suggests that hepatocytes and IL-15 create a favorable microenvironment for T cells to growth and survive. It can be proposed that the increased percentage of intrahepatic nonclassical NKT cells could be in part due to a local CD8(+) T cell differentiation.

DOI: 10.4049/jimmunol.0802470

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@article{Correia2009HepatocytesAI, title={Hepatocytes and IL-15: a favorable microenvironment for T cell survival and CD8+ T cell differentiation.}, author={Margareta P. Correia and Elsa Maria Cardoso and Carlos Filipe Pereira and Rui P L Neves and Markus Uhrberg and Fernando A. Arosa}, journal={Journal of immunology}, year={2009}, volume={182 10}, pages={6149-59} }