(A) ELISA measurement of IL-12 secretion by poly I:C–stimulated BMDCs of the indicated genotypes

(B) Flow cytometric analysis of DC activation after poly I:C stimulation. Histograms of poly I:C–stimulated DCs (gray-filled histograms) of the indicated genotypes indicating surface expression levels of the surface activation markers CD40 and CD86. (C) ELISA determination of IFN-γ secretion by NK cells co-cultured with WT, 15KO, RαKO, or mixed 15KO:RαKO BMDCs. BMDCs were treated with PBS or poly I:C for 18 h, after which NK cells were co-cultured with activated DCs for an additional 6 h. Poly I:C–stimulated cultures are indicated by black bars, and PBS-stimulated control cultures are indicated by white bars. Note that significant poly I:C–induced NK cell activation occurs only in the presence of WT DCs. (D and E) Flow cytometric measurement of NK cell (NK1.1) activation by poly I:C (p(I:C)) –stimulated DC–NK cell co-cultures. Elevated CD69 surface staining reflects initial (TLR-dependent, IL-15–independent) activation of NK cells. IFN-γ and granzyme B expression by NK cells were performed by intracellular staining 6 and 12 h after stimulation, respectively. Numbers indicate the percentage of cells in the indicated gate. Note that NK cells express significant levels of both IFN-γ and granzyme B only when activated by WT DCs. Plots are representative of three separate experiments.<p><b>Copyright information:</b></p><p>Taken from "IL-15Rα chaperones IL-15 to stable dendritic cell membrane complexes that activate NK cells via trans presentation"</p><p></p><p>The Journal of Experimental Medicine 2008;205(5):1213-1225.</p><p>Published online 12 May 2008</p><p>PMCID:PMC2373851.</p><p>