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. 2023 Nov 2;11(11):e006702. doi: 10.1136/jitc-2023-006702

Figure 1.

Figure 1

Intraperitoneal administration of MVA.scIL-12 induces a potent antitumor-specific immune response in the MC38 colon cancer model of peritoneal carcinomatosis. (A) C57BL/6 mice were challenged i.p. with 5×105 MC38 colon cancer cells. Seven days later, mice were treated i.p. with PBS (control) or 5×107 TCID50 of the indicated MVA constructs. Mice were followed to assess survival or some mice were sacrificed 1 week after vector inoculation, and splenocytes and peritoneal washing fluids were collected to assess antitumor immune response. (B) IFN-γ–producing cells measured by ELISpot in splenocytes stimulated with the p15E604-611 antigen, or with colon cancer cells. (C) Percentage of gp70 tetramer+ in the CD8+ T lymphocytes in the spleen and the peritoneal washing fluids. (D) Percentage of cells producing IFN-γ, TNF-α in CD8+ T lymphocytes in the spleen and the peritoneal washing fluids. (E) Kaplan-Meier survival curve and representative images of the peritoneal washing fluids on day 14 or of the peritoneum on day 23. (F) Mice that eliminated tumor cells were rechallenged with an intraperitoneal injection of 5×105 MC38 cells. The Kaplan-Meier survival curve is shown. (G) C57BL/6 mice were challenged i.p. with 5×105 MC38 colon cancer cells. Seven days later, mice were treated i.p. with PBS (control) or 5×107 TCID50 of MVA.scIL-12. The treated mice received an irrelevant antibody or an antibody to deplete CD8+ T, CD4+ T lymphocytes or NK cells on days −2, 0, 2, 6, 9, and 13 (additional doses on days 16, 20, and 24 for NK cells depletion), being 0 the day of the start of treatment. Kaplan-Meier survival curve is shown. Data are expressed as mean±SEM. The results are representative of two independent experiments. Two-way ANOVA was performed followed by Sidak’s post-test. **p<0.01; ***p<0.005. ANOVA, analysis of variance; ELISpot, enzyme-linked immunosorbent spot; IFN, interferon; i.p., intraperitoneal; MVA, modified vaccinia virus Ankara; MVA.scIL-12, MVA encoding scIL-12; NK, natural killer; PBS, phosphate-buffered saline; PCa, peritoneal carcinomatosis; scIL-12, single-chain interleukin 12; TCID50, 50% tissue culture infectious dose; TNF, tumor necrosis factor.