title: NK-cell activation by LIGHT triggers tumor-specific CD8+ T-cell immunity to reject established tumors.
abstract: Natural killer (NK) cells are generally reported as innate effector cells for killing virally infected and transformed cells. It is unclear how NK cells evoke adaptive immunity to eradicate tumors. We now demonstrate that the TNF superfamily member, LIGHT, known as TNFSF14 and a T-cell costimulatory molecule, is a critical ligand for the activation of NK cells. Herpesvirus entry mediator (HVEM) is expressed on NK cells, and its engagement with LIGHT mediates NK-cell activation. The expression of LIGHT inside tumors leads to rapid rejection in a NK-dependent manner. Both NK and CD8+ cells are essential but not sufficient for the rejection of tumors because mice lacking either population fail to reject the tumor. Interestingly, activated NK cells do not kill tumors directly but can facilitate the priming of tumor-specific CD8+ T cells in an IFN-gamma-dependent manner. Conversely, intratumor depletion of either NK cells or IFN-gamma during tumor progression disrupts CD8+ cell-mediated tumor rejection, suggesting that the tumor is the essential site for the crosstalk between NK and CD8+ cells. Furthermore, IFNG-deficient NK cells fail to effectively activate CD8+ T cells, suggesting IFN-gamma plays an important role in NK-mediated activation of cytotoxic T lymphocytes (CTLs). Our findings establish a direct role for LIGHT in NK activation/expansion and a critical helper role of activated NK cells in priming CD8+ T cells and breaking T-cell tolerance at the tumor site.
authors.affiliation: National Laboratory of Biomacromolecules and Center for Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Rd, Chaoyang District, Beijing 100101, China. fanz@moon.ibp.ac.cn
authors.forename: Zusen
authors.initials: Z
authors.lastname: Fan
authors.forename: Ping
authors.initials: P
authors.lastname: Yu
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Yugang
authors.initials: Y
authors.lastname: Wang
authors.forename: May Lynne
authors.initials: ML
authors.lastname: Fu
authors.forename: Wenhua
authors.initials: W
authors.lastname: Liu
authors.forename: Yonglian
authors.initials: Y
authors.lastname: Sun
authors.forename: Yang-Xin
authors.initials: YX
authors.lastname: Fu
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D045744:Cell Line, Tumor; D005260:Female; D005354:Fibrosarcoma / Q000276:immunology*; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009374:Neoplasms, Experimental / Q000276:immunology; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
chemical_list: D008565:Membrane Proteins; C505915:Tnfsf14 protein, mouse; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma