Figure 4.

β-GlcCer presented by CD1d activates iNKT cells via cognate TCR interaction. (a) CD1d was loaded with equal molar concentrations of the indicated lipid. Loaded CD1d, or mock-loaded bovine serum albumin (BSA), was plate-bound and used to stimulate a primary murine iNKT cell line. IFN-γ ELISA data are presented as mean and range in duplicate wells. (b) Freshly-isolated splenocytes from C57Bl/6 and BALB/c mice were co-stained with PBS-57 CD1d tetramer and unloaded or β-GlcCer C_24:1-loaded CD1d tetramer. TCRβ⁺CD19^-cells are shown, and the percentage of iNKT cells that stained positive with β-GlcCer C_24:1-loaded tetramer is shown. (c) C57Bl/6 splenocytes were stained with β-GlcCer C_24:1 CD1d tetramer and the TCR V_β antibody indicated above each plot. The CD3 molecular complex⁺CD19^-PBS-57 tetramer⁺ gate is shown in each plot, with quadrants based on unloaded tetramer staining. (d) The percentage of iNKT cells from the β-GlcCer C_24:1 tetramer⁺ population bearing each indicated TCR V_β, with data presented as mean + s.e.m. from three separate experiments.