Figure 3.

Bone toxicity and cachexia in mice treated with FAP5-CAR T cells. Irradiated mice were treated with 2 × 10⁷ UnTd or FAP5-CAR Td T cells, and 7 d later subjected to a comprehensive necropsy. H&E-stained cross section of the femurs from mice treated with UnTd (A) or FAP5-CAR Td (B) T cells. Bars, 400 µm. Femurs and tibias of irradiated and nonirradiated mice that did not undergo adoptive cell transfer (No Tx) or that underwent adoptive transfer with UnTd or FAP5-CAR Td T cells were harvested at day 7 (2 mice pooled per group), and BM (C) and OS (D) cells were isolated and live cells quantitated. Mean ± SD. Data are the average number of cells isolated from the femurs and tibiae of one mouse, and are representative of at least two independent experiments. *, P < 0.01 compared with UnTd and No Tx in their respective group, by two tailed Student’s t test. Average weights of irradiated (E) or nonirradiated (F) mice treated with 2 × 10⁷ UnTd or FAP5-CAR Td T cells (5 mice per group). Results are representative at least three independent experiments. Rag1-deficient mice bearing the human pancreatic cancer xenograft HPAC were sacrificed between days 18–21 and tumors were harvested and assessed for FAP expression by IHC using biotinylated-FAP5 (G). Bar, 400 µm. Representative of at least two independent experiments. Rag1-deficient mice bearing established HPAC tumors (50–70 mm²) were treated with 10⁷ UnTd or FAP5-CAR Td mouse T cells. Shown are weights on day 0 and day 7 (H). Mean ± SEM. Each group initially contained five mice. Similar results were seen in mice treated with 5 × 10⁶ FAP5-CAR Td T cells in three independent experiments.