αGC-loaded CD1d-CD19 fusion promotes hu-iNKT cell-mediated transactivation of other immune cells in vitro. Freshly isolated hu-iNKT cells were mixed with autologous PBMCs at a 1:1 ratio (2 × 105 PBMCs: 2 × 105 NKT cells). Control wells had PBMCs only (4 × 105 cells). Cells were added to wells precoated with αGC-loaded or unloaded CD1d-CD19 fusion (1 μg/mL). After 24 hours, cells were harvested and analyzed for surface expression of HLA and costimulatory molecules on CD19+ B cells (A) and CD11c+ myeloid cells (B) by flow cytometry. (C) From the same experiments, culture supernatants were harvested and analyzed for cytokines as in Figure 2. Data are presented as mean ± SEM and compiled from independent experiments using autologous PBMCs and purified iNKT cells from 3 normal human donors. CD69 (D) and CD107a (E) expression was determined on different immune cell populations by flow cytometry. Data shown in panels A-B and D-E are representative histograms from 3 independent experiments. Numbers in the histograms indicate MFI. Significance was determined by unpaired 2-tailed Student t test. **P < .01.