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 2
Binding and biological activity of recombinant CD1d molecules. (A) Binding of the sCD1d–anti-HER2 protein to HER2-expressing target cells, and recognition by FITC-labeled anti-CD1d. HER2-positive target cells (B16-HER2 and SKBR3) are recognized while HER2-negative LoVo cells are not. (B) Titration of the binding of the sCD1d–anti-HER2 scFv protein or the full anti-HER2 antibody Herceptin to B16-HER2 cells. Detection was performed using anti-CD1d–FITC and anti-human IgG FITC, respectively. (C) In vivo bioactivity of αGalCer-loaded sCD1d and sCD1d–anti-HER2, shown by the transient disappearance of liver iNKT cells secondary to the activation-induced downmodulation of the invariant T cell receptor. Liver lymphocytes were analyzed for numbers of iNKT cells 20 hours after i.p. injection of PBS (control) and 5 μg αGalCer, 20 μg unloaded or αGalCer-loaded sCD1d, 40 μg unloaded or αGalCer-loaded sCD1d–anti-HER2 fusion. Detection by FACS using PE-labeled αGalCer/CD1d-tetramer and FITC-labeled anti-CD3. Results are expressed in percent of iNKT cells from total liver lymphocytes.