IFN-γ production in co-culture experiments treated with IL-10 and IL-18 blockade. Freshly isolated human liver sinusoidal NK cells and Kupffer cells from adult live donors were co-cultured and stimulated by TLR agonists for 16 h in the presence or absence of anti–IL-10 (A) or anti– IL-18 (B) antibodies. Media and IL-12/15 served as negative and positive controls, respectively. The percentages of IFN-γ–positive cells were measured by flow cytometry (A and B, top). Supernatants were collected, and cytokine protein content was measured by CBA (A and B, bottom). The dramatic effects of IL-10 blockade are seen in LTA- and LPS-stimulated cells (A). The effects on poly I:C–stimulated cells were not significant in terms of the percentage of NK cells synthesizing IFN-γ, whereas they were significant in terms of IFN-γ secretion. On the other hand, IL-18 blockade significantly inhibited IFN-γ synthesis induced by all three ligands, and such inhibition was also significant in terms of secreted IFN-γ for LTA and poly I:C (B).