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. 2021 Jun 2;9(6):e002181. doi: 10.1136/jitc-2020-002181

Figure 3.

Figure 3

Immune checkpoint inhibitor (ICI) treatment of SB28 subcutaneous tumors can elicit systemic memory and requires similar immune subsets to those involved in natural immune surveillance. (A) Schematic illustration of dosing schedule for SB28 intracerebral tumor rechallenge. (B) Mice previously cured of SB28 subcutaneous tumors (pink line) were rechallenged with SB28 intracerebral tumors. Survival was compared to naive mice (gray line) challenged with SB28 intracerebral tumors and illustrated in a Kaplan-Meier curve. No treatments were administered. (C) Volcano plot comparing abundance of immune subpopulations in dissociated subcutaneous SB28 tumors on day 12 after ICI treatment (orange) versus isotype control treatment (black), using the mouse immune cell panel. Statistically significant clusters in volcano plots are highlighted in opaque color and indicated with a cell type label. (D) Volcano plot as in (C) comparing abundance of immune subpopulations in dissociated subcutaneous SB28 tumors on day 27–29 (brown) versus day 12 (black). (E) Tumor volume measurements of SB28 subcutaneous tumors treated with control IgG (gray) or ICI in the context of either CD4 T cell depletion (light green), CD8 T cell depletion (blue), CD40L blockade (orange), or NK cell depletion (dark green). Depleting or blocking antibodies were administered starting on day −3 or day 0, as described in online supplemental table S6. ICI was administered on days 7, 9, 12, 14, 16 as indicated (arrows). Statistical test: repeated measures two-way analysis of variance (ANOVA; ***p≤0.001; *p≤0.05; n.s.: p>0.05). Error bars: SEM. TAM, tumor-associated macrophage; TIME, tumor immune microenvironment.