Figure 2

Intratumoral immunotherapy is ineffective in the setting advanced tumor burden, and but produces functionally enhanced CD8 T-cells. (A) C57BL/6 mice bearing locally advanced TC1 tumors (~750mm³) were randomized to treatment with AdV-tk/GCV, Ad.IFNα or Ad.LacZ/GCV (control) and tumor volume was recorded. No difference tumor growth was appreciated. (B) Mice (n = 5) bearing TC1 tumors of varying sizes (200mm³, 400mm³, 600 mm³ and 800mm³) were treated with AdV-tk/GCV. Mice (n = 5) bearing tumors measuring 200mm³ were treated with Ad.LacZ/GCV as a control. As can be seen, AdV-tk/GCV loses effectiveness as tumor burden increases as exemplified by tumor volume at Day 22. (C) Mice bearing LKR tumors, a spontaneously metastatic NSCLC line, were treated with AdV-tk/GCV, Ad.IFNα or Ad.LacZ/GCV (control) at a time point in which lung metastases are known to be present. Lungs were harvest at Day 42 and analyzed for tumor burden. Lung surface area involved with tumor burden was compared, and no difference was appreciated among groups. (D) in vivo tumor neutralization assay —Fresh TC1 tumor cells were mixed with (i) CD8 T-cells from mice receiving Ad.LacZ/GCV, (ii) CD8 T-cells form mice receiving AdV-tk/GCV and (iii) CD8 T-cells from tumor naïve mice and mixed into mice (n = 5). TC1 tumor cells were injected alone to confirm tumor cell viability. Trends toward enhanced CD8 T-cell function with intratumoral previous exposure were appreciated. * Represents a p < 0.05, ** represents a p < 0.01.