Figure 7.

Ex Vivo Analyses of Additional MDA-MB-231.GFP-CaaX Tumor-Bearing Cohorts

(A) Experimental scheme. (B) Ex vivo analysis of radioactivity in harvested tissues from three different cohorts: animals that received T4NT CAR T cells intratumorally and were sacrificed either on the day after administration (red) or two weeks later (light red), and control animals that received untransduced T cells and were culled two weeks after administration. Shown are cumulative quantified by γ-counting data from all animals. Signal levels after 15 days were indistinguishable between animals that had received CAR T cells and untransduced T cells (p = 0.4425) while differences compared to day 1 were significant (p < 0.05 for both); error bars are SD. (C) Immunofluorescence histology demonstrating T4NT CAR T cell presence at injection sites on day 1 after administration (by anti-human CD3 staining. Tumor cells are visualized by GFP staining. Representative micrographs are shown. Data in (B) and (C) confirm observations from Figure 6. (D) Typical magnified micrograph of a MDA-MB-231.GFP-CaaX tumor on day 1 after T4NT CAR T cell administration. It shows that T4NT CAR T cells did not infiltrate into the adjacent tumor mass and a virtual boundary (white dashed line) was drawn indicating the two zones. Reduced GFP-CaaX signals in the area where T4NT CAR T cells were present indicated loss of tumor cells in this area. All scale bars in (C) and (D) are 100 μm.