Two-photon imaging of intratumoral CD8⁺ T cell cytotoxic activity during adoptive T cell therapy in mice
J. Clin. Invest. Béatrice Breart, et al. 118:1390 doi:10.1172/JCI34388 [Go to this article.]

Figure 6
In vivo primed CTLs failed to control tumor growth despite exhibiting effective cytotoxic activity at the tumor site. (A) Naive OT-I CD8⁺ T cells (5 × 10⁶ cells) were adoptively transferred 3 days after the mice were injected with a mixture of EL4-mCFP and EG7-mYFP tumor cells. Representative confocal images of tumor sections indicate a distinct level of CTL infiltration. EG7 tumor cells were eliminated in the CTL-rich area, which indicated in situ cytotoxic activity (right). Little to no EG7 killing was detected in regions of the tumor with little CTL infiltration (left). Scale bars: 100 μm. (B) Naive OT-I CD8⁺ T cells were adoptively transferred in mice injected with EG7-DEVD tumor cells. Representative images indicate that in vivo primed CTLs (red) were closely associated with apoptotic tumor cells (green).