Figure 4.

Elimination of NO by C-PTIO potentiates the antitumor activity of CTLs. (A) B16 melanoma cells (1 × 10⁶) were implanted intradermally in C57BL/6 mice. Mice were divided into four groups: untreated, Carboxy-PTIO-treated, CTL-treated or CTL and C-PTIO-treated (5–7 mice per group). Nine days later (designated as day 0), tumor-bearing mice received 1 × 10⁷ CTLs. From day 1 to day 10, C-PTIO (2 mg/200 μl PBS) was injected twice daily i.p. Tumor growth was measured every other day. (B) Mice (n = 3 per group) were killed on day 3 and NO expression in CD11b⁺Gr1⁺ MDSCs was compared between CTL-treated mice and CTL+C-PTIO-treated mice.