Shaping of adaptive immunity by innate interactions.
In inflamed tissues, the reciprocal interaction between Natural Killer (NK) cells and Dendritic Cells (DC) results in a potent activating cross talk that leads to DC maturation and NK cell activation with acquisition of NK-mediated cytotoxicity against immature DC (iDC). We focused our studies on NK-mediated killing of monocyte-derived iDC and we provided evidence that NK cells that express CD94/NKG2A but not killer Ig-like receptors (KIR) are able to kill autologous iDC. Indeed HLA-E (i.e. the cellular ligand of CD94/NKG2A) is sharply reduced in iDC, whereas it is partially recovered in mDC. The latter are lysed only by a small fraction of NK clones characterized by low levels of CD94/NKG2A expression. Another NK receptor, whose surface density is crucial for the ability to kill iDC, is represented by NKp30, a member of the NCR (Natural Cytotoxicity Receptor) family. We showed that transforming growth factor beta1 (TGFbeta1) treatment results in specific downregulation of NKp30 expression. This effect profoundly inhibits the NK-mediated killing of DC suggesting a possible mechanism by which TGFbeta1-producing DC may acquire resistance to the NK-mediated attack.
Dipartimento di Medicina Sperimentille, Università degli Studi di Genova, Italy.
Roberta
R
Castriconi
Mariella
M
Della Chiesa
Alessandro
A
Moretta
D000818:Animals; D002450:Cell Communication / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation; D009000:Monocytes / Q000276:immunology