Sustained activation and tumor targeting of NKT cells using a CD1d–anti-HER2–scFv fusion protein induce antitumor effects in mice
J. Clin. Invest. Kathrin Stirnemann, et al. 118:994 doi:10.1172/JCI33249 [Go to this article.]

Figure 6
Activated iNKT cells retain their capacity to transactivate NK cells and promote DC maturation. Production of IFNγ by NK cells in the same mice analyzed in Figure 5, ex vivo 20 min after an i.v. injection (A) or after in vitro rechallenge (B). NK population was gated on NK1.1 single positive cells. (A) Results are expressed as percent of IFNγ-producing NK cells. (B) Same legend as in Figure 5B. *P < 0.05; **P < 0.0006. (C) The antitumor activity is in great part lost after NK cell depletion. Three groups of mice were grafted s.c. with 700,000 B16-HER2 cells, and 2 groups were treated with the αGalCer/sCD1d–anti-HER2 fusion 7 days later when tumors were palpable. For NK cell depletion, 1 of these groups was repeatedly i.p. injected with anti-asialo–GM1 antibodies during the whole treatment with the αGalCer/sCD1d–anti-HER2 protein. Results represent the kinetic of s.c. tumor growth (in mm³) as the mean ± SD of 4 mice per group. (D) Induction of DC maturation by αGalCer/sCD1d-activated iNKT cells. Splenocytes were isolated 16 hours after the third i.v. injection of PBS (control), equimolar amounts of αGalCer (0.4 μg), or αGalCer-loaded sCD1d (25 μg). DCs were sorted with anti-CD11c magnetic beads and stained with anti-CD11c–FITC and either biotinylated with anti-CD80, anti-CD86, or anti-CD40 antibodies followed by Streptavidin-PE. Results show the 3 activation markers on gated CD11c-positive cells, and numbers indicate the percent of cells with upregulated marker.