Fig. 1
Sensing of viral PAMPs triggers NK cell activation and cytokine secretion. NK cells were activated overnight in round-bottom 96-well plates (2.5 × 105 cells/well) with viral PAMPs in the absence (white bars) or presence (gray bars) of IL-2 in serum-free medium. As a negative control, NK cells were incubated with medium alone. a After 16-18 h of incubation IFN-γ, TNF-α, CCL3, and CCL5 were determined in the culture supernatant by CBA. b After 16-18 h of incubation cells were harvested and stained for CD69, CD25, and CD83. Expression of these markers was analysed by flow cytometry. All data are presented as mean + SEM and are representative of at least 3 independent experiments (3 ≤ n ≤ 12). After an initial screening of at least 3 independent experiments for each ligand, future experiments were peformed mainly with the ligands showing a positive effect on NK cell activation. Kruskal-Wallis test significance as compared to negative control with and without IL-2, respectively. * P≤0.05, **** P≤0.0001