Figure 2.

Specificity of CD1d–α-GalCer tetramers. (a–d) Vα24⁺/Vβ11⁺ T cells were expanded after stimulation of PBMC with α-GalCer and were stained with CD1d tetramers and antibodies shown in the figure. Cells in d were incubated first with unlabeled anti-Vα24 and anti-Vβ11 antibodies and subsequently stained with FITC-conjugated anti-Vα24 antibody and CD1d–α-GalCer tetramers. All density plots were gated on the CD3⁺ propidium iodide⁻ cells. (e) CD4⁺ CD1d–α-GalCer tetramer⁺ cells were sorted from an in vitro-expanded α-GalCer-stimulated T cell line containing 0.59% positive cells. Enrichment for NKT cells was confirmed by using anti-Vα24 and -Vβ11 antibodies after two rounds of stimulation.