Fig. 3.

The immunogenic self-lipid antigens are loaded onto CD1d molecules in the endosomal/lysosomal recycling pathway in ER-stressed APCs. Thapsigargin-treated THP1 cells overexpressing full length CD1d (THP1-CD1d), CD1d with a deletion of 11 amino acids in the cytoplasmic tail domain (THP1-CD1d tail^−/−) and GPI-linked CD1d (THP1-CD1d GPI) were cocultured with human iNKT cells. As a control, the THP1 cell lines were treated with C20:2. iNKT cell activation was measured by (A) IFN-γ secretion and (B) CD25 surface expression. Experiments are representative of n = 3. *P < 0.05 and **P < 0.005 by a 1-way ANOVA with a Dunnett’s multiple comparison posttest.