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 1
Antigen-specific tumor regression upon adoptive transfer of in vitro primed CTLs. C57BL/6 mice were injected s.c. with 2 × 10⁶ EL4 tumor cells or with the OVA-expressing variant EG7 expressing mCFP or mYFP, respectively. On day 5, mice were adoptively transferred with 5 × 10⁶ OT-I CD8⁺ T cells that were activated in vitro for 48 hours. A second group of recipient mice were adoptively transferred with 5 × 10⁶ naive OT-I CD8⁺ T cells. Naive OT-I CD8⁺ T cells were transferred on day 3 to allow additional time for in vivo activation. (A) Tumor growth was followed over time. In vitro, but not in vivo, primed OT-I CD8⁺ T cells induced complete regression of EG7 tumors. (B) Confocal images of tumor frozen sections 5–7 days following adoptive transfer of naive or in vitro activated OT-I T cells. Most EG7-mYFP tumor cells were rapidly eliminated after transfer of activated OT-I CD8⁺ T cells but not after transfer of naive OT-I CD8⁺ T cells. Scale bars: 100 μm.