Figure 2.

Allogeneic natural killer (NK) cells from WT mice fed with control diet (CD) expanded less and mediated less cytotoxicity, but demonstrated augmented IFN-γ secretion when cultured with osteoclasts from KC mice fed with high-fat calorie diet. WT and KC mice were fed with a CD or high-fat calorie diet as described in Section “Materials and Methods.” Bone marrow was harvested after animals were sacrificed and single cell suspension was prepared as described in Section “Materials and Methods.” Monocytes were purified from the BM cells and were used to generate OCs as described in Section “Materials and Methods.” Flow cytometric analysis was used to determine expression of RAE1-delta and MHC-class I on day 21 mature OCs (A). NK cells purified from splenocytes of WT mice fed with CD were activated with IL-2 (10,000 U/ml) and LPS (100 ng/ml), and cultured in the presence/absence of OCs from different mouse groups at NK:OCs; 1:0.5 ratio, and the number of expanded NK cells were determined on the days shown in the (B). NK cells expanded by the OCs as described in (B) were used as effector cells in a standard 4-h ⁵¹Chromium release assay. The LUs 30/106 cells were determined as described in Figure 1B (C). NK cells were purified from WT splenocytes and cultured with OCs as described in (B,D,E) or treated with IL-2 in the presence of sonicated AJ2 (sAJ2) and cultured with OCs at the ratio of (0.5:1:2; OCs:NK:sAJ2) (F,G) and the supernatants were harvested on the days shown in the figures and secretion of IFN-γ were determined. One of three representative experiments is shown in Figure 2.