Figure 3. Effective TCR signaling of αGalCer-pretreated iNKT cells.

(A and B) Control Nur77^GFP mice and Nur77^GFP mice injected 1 month earlier with 4 μg αGalCer (Nur77^GFP/αGC) were challenged i.v. with 1 μg αGalCer, and GFP expression by splenic iNKT cells was analyzed 1 hour later. Representative data (A) and a summary graph of the GFP⁺ cells (B) are shown. αGalCer-pre, αGalCer pretreatment. Expression levels of unstimulated iNKT cells from C57BL/6 (B6) mice are shown in A as a negative control. (C) Enriched splenocytes from control congenic C57BL/6 mice (CD45.1⁺) and from C57BL/6 mice (CD45.2⁺) injected 1 month earlier with 4 μg αGalCer (B6/αGC) were mixed and stimulated by cross-linking with αCD3ε antibodies. Two minutes later, cells were fixed, and the expression of p-ERK1/2 by indicated iNKT cells was analyzed. Numbers in the histograms denote the geometric mean values for the depicted antigen in iNKT cells. Representative data from at least 2 independent experiments are shown in each panel.