1. Fig. 7. mRIPO therapy restricts tumor growth and produces antigen-specific antitumor immunity.
mRIPO therapy restricts tumor growth and produces antigen-specific antitumor immunity. (A) Cytopathogenicity profile of mRIPO in B16-F10.9-OVA-CD155 cells. (B and C) Subcutaneous B16-F10.9-OVA-CD155 tumors were injected with either control (DMEM) or mRIPO (20 μl) when they reached a volume of ~50 to 100 mm3. Tumor volume was measured (n = 11 per group) on the days indicated (B); mice were euthanized when tumors reached 1000 mm3 (C). Data are from two pooled assays. Tumor growth curves were compared using multiple t tests with Holm-Sidak multiple comparison posttest; P ≤ starting on day 6. Comparison of survival curves between the two groups was performed using the log-rank test (Mantel-Cox test), P < Median survival day: control, 14; mRIPO, 24. (D) Tumor-draining inguinal lymph nodes were harvested from mice (n = 4) 7 days after treatment with DMEM or mRIPO and restimulated with antigen-expressing cells for 5 days. Restimulated cells were tested for lytic activity against B16-F10.9-OVA cells or EL4 cells electroporated with RNA encoding GFP (control), TRP-2 (melanoma antigen), or OVA. (E) Supernatant from the CTL assay (D) was tested for markers of T cell activation and lytic activity by ELISA. (F) Tumor-bearing mice were treated with DMEM or mRIPO, and spleens were harvested 14 days after treatment (n = 4). Splenocytes from individual mice were cocultured with B16-F10.9-OVA-CD155 cells (5:1 ratio; 48 hours); supernatant was tested as in (E). (G) Tumor-draining inguinal lymph nodes were harvested after treatment with DMEM or mRIPO and individually restimulated in vitro. After 5 days, restimulated cells were analyzed for CD4 and CD8 T cells by flow cytometry. TRP-2–specific response was assessed using an H-2Kb TRP-2 tetramer (right panel). TRP-2–specific responses were compared using Student’s t test, with P < 0.05 considered significant. Figure S8D shows representative flow cytometry analyses of T cells and TRP-2–specific T cells (out of the four tested per group).
Michael C. Brown et al., Sci Transl Med 2017;9:eaan4220
Published by AAAS