Fig. 2.
Effect of LIGHT-expressing Salmonella on tumor growth. (A) BALB/c mice (n = 8) were injected s.c. with 1.25 × 105 D2F2 breast carcinoma cells. After 14 days, when tumors reached ≈50 mm3, mice were injected i.v. with PBS (♦), untransformed Salmonella (■), Salmonella containing empty vector (▴), or Salmonella with LIGHT-expression plasmid (○). Tumor volumes (mm3) were estimated by external calipers (mean ± SD). (B) Mice were injected s.c. with 2.5 × 105 CT-26 colon carcinoma cells and injected i.v. with untransformed Salmonella (■), Salmonella containing empty vector (▴), or Salmonella containing LIGHT expression plasmid (○) after 9, 14, and 19 days. External tumor volumes were measured (mean ± SD; n = 5). (C–E) Mice (n = 8) were injected i.v. with 5 × 104 D2F2 breast carcinoma cells and then injected i.v. with PBS, untransformed Salmonella (Sal), Salmonella containing empty vector (Sal + vector), or Salmonella containing LIGHT plasmid (Sal + LIGHT) after 6, 13, and 20 days. After 50 days, animals were killed, and lungs were weighed (mean ± SEM; normal lung weight ∼0.15 g) (C), photographed (representative lungs shown) (D), and scored for metastases (E), assessing the percentage of lung surface covered by metastases: 0 = 0%, 1 = <20%, 2 = 20–50%, 3 = >50%. *, P < 0.05.