title: NK cells provide helper signal for CD8+ T cells by inducing the expression of membrane-bound IL-15 on DCs.
abstract: NK cell recognition of cells that do not express or express low amounts of MHC class I molecules results not only in direct killing of target cells but also in the generation of specific T cell responses consequent to the induction of dendritic cell (DC) activation. While IL-12 production by NK cell-activated DCs is generally thought to play a critical role, a similar DC-mediated NK cell help has been reported also in IL-12-knockout mice. Here, we show that human NK cells can induce on DC surface membrane, via IFN-gamma secretion, the expression of high levels of IL-15. Remarkably, we show that DC expression of this membrane-bound form of IL-15, which is only partially associated with IL-15R molecules, is essential to promote specific CD8(+) T lymphocyte response in the absence of DC-derived IL-12.
authors.affiliation: Laboratory of Immunology and Biotherapy, Department of Human Pathology, University of Messina, Messina, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Morandi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Mortara
authors.forename: Paolo
authors.initials: P
authors.lastname: Carrega
authors.forename: Claudia
authors.initials: C
authors.lastname: Cantoni
authors.forename: Gregorio
authors.initials: G
authors.lastname: Costa
authors.forename: Roberto S
authors.initials: RS
authors.lastname: Accolla
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Mingari
authors.forename: Silvano
authors.initials: S
authors.lastname: Ferrini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Moretta
authors.forename: Guido
authors.initials: G
authors.lastname: Ferlazzo