Figure 5.
Effect of ara operon-deleted S. typhimurium on tumor growth. BALB/c mice were inoculated subcutaneously with CT26 cells (1 × 106). When the tumor volume reached ∼120 mm3, mice were injected with PBS (n = 6), SL carrying pClyA (SL- pClyA, n = 6), or SLΔARA carrying pClyA (SLΔARA- pClyA, n = 7), but were not treated with L-arabinose (-). In separate groups (n = 8 per group), mice were injected with SL- pClyA or SLΔARA- pClyA, and then received a daily intraperitoneal injection of 120 mg L-arabinose (+), starting 3 d after they had received the bacteria. (A) Changes in tumor volume. * P = 0.04 (PBS vs. SL-pClyA (-) or SLΔARA- pClyA (-) at day 15, SL- pClyA (+) vs. SLΔARA- pClyA (+) at day 24), ** P = 0.03 (SL-pClyA (-) vs. SL-pClyA (+) at day 21, SLΔARA- pClyA (-) vs. SLΔARA- pClyA (+) at day 21, SL-pClyA (-) vs. SLΔARA- pClyA (+) at day 21) (B) Images of subcutaneous tumors in representative mice. (C) Western blot analysis of the 34 kDa ClyA protein from CT26 tumor tissues of mice injected with SL- pClyA or SLΔARA- pClyA, and with or without L-arabinose induction.