Figure 5.

Thy-1 cross-linking boosts α-galactosylceramide (αGC)-mediated cytokine secretion by primary mouse natural killer (NKT) cells. Hepatic lymphoid mononuclear cells were stained with a FITC-conjugated anti-T-cell receptor-β (TCR β) mAb, a phycoerythrin-conjugated anti-NK1.1 monoclonal antibody and either PBS-57-loaded or -unloaded CD1d tetramer (labelled with allophycocyanin). TCR-β⁺ NK1.1⁺ cells were gated on (a; left panels) and assessed for their reactivity with CD1d tetramer reagents (a; right panels). Highly pure TCR β⁺ NK1.1⁺ hepatic NKT cells were sorted and co-cultured with bone marrow-derived dendritic cells at a ratio of five iNKT cells to one bone marrow-derived dendritic cell. Cells were incubated with αGC alone (100 ng/ml), a low (5 μg/ml) or high (40 μg/ml) dose of G7, or a combination αGC and G7. After 48 hr, culture supernatants were harvested and interferon-γ (IFN-γ) levels (b) and interleukin-4 (IL-4) levels (c) were measured by ELISA. Statistical significance is denoted by asterisks, where ** and *** represent P < 0·01 and P < 0·001, respectively.