Depleting tumor-specific Tregs at a single site eradicates disseminated tumors
Aurélien Marabelle, … , Victor Tse, Ronald Levy
Aurélien Marabelle, … , Victor Tse, Ronald Levy
Published May 24, 2013
Citation Information: J Clin Invest. 2013;123(6):2447-2463. https://doi.org/10.1172/JCI64859.
View: Text | PDF | Erratum
Research Article

Depleting tumor-specific Tregs at a single site eradicates disseminated tumors

Abstract

Activation of TLR9 by direct injection of unmethylated CpG nucleotides into a tumor can induce a therapeutic immune response; however, Tregs eventually inhibit the antitumor immune response and thereby limit the power of cancer immunotherapies. In tumor-bearing mice, we found that Tregs within the tumor preferentially express the cell surface markers CTLA-4 and OX40. We show that intratumoral coinjection of anti–CTLA-4 and anti-OX40 together with CpG depleted tumor-infiltrating Tregs. This in situ immunomodulation, which was performed with low doses of antibodies in a single tumor, generated a systemic antitumor immune response that eradicated disseminated disease in mice. Further, this treatment modality was effective against established CNS lymphoma with leptomeningeal metastases, sites that are usually considered to be tumor cell sanctuaries in the context of conventional systemic therapy. These results demonstrate that antitumor immune effectors elicited by local immunomodulation can eradicate tumor cells at distant sites. We propose that, rather than using mAbs to target cancer cells systemically, mAbs could be used to target the tumor infiltrative immune cells locally, thereby eliciting a systemic immune response.

Authors

Aurélien Marabelle, Holbrook Kohrt, Idit Sagiv-Barfi, Bahareh Ajami, Robert C. Axtell, Gang Zhou, Ranjani Rajapaksa, Michael R. Green, James Torchia, Joshua Brody, Richard Luong, Michael D. Rosenblum, Lawrence Steinman, Hyam I. Levitsky, Victor Tse, Ronald Levy

×

Figure 5

Depletion of tumor-specific Tregs at the injected site.

Options: View larger image (or click on image) Download as PowerPoint
Depletion of tumor-specific Tregs at the injected site. (A) OVA-specific...
(A) OVA-specific CD4+ T cells negatively selected from DO11.10 mice were stained with violet dye and injected into 7-day-old A20-OVA tumors of WT mice. Four days later, the tumors were treated or not with CpG plus low-dose αOX40/CTLA4. Tumor-infiltrating OVA-specific CD4+ T cells were analyzed 4 days after beginning therapy. Data are representative of cohorts of 3 mice. (B) Proportions of CD25+ and FOXP3+ cells within OVA-specific (KJ1-26+) CD4+ cells from untreated and treated A20-OVA tumors. Seven days after A20-OVA tumor challenge, 1 site was injected with 1.8 × 106 OVA-specific CD4 cells purified from DO11.10 mice. Four days later, 1 group of mice received 1 day of CpG and low-dose αOX40/CTLA4 in these tumors, followed by 2 days of i.t. CpG alone; the phenotype of OVA-specific CD4 cells was analyzed by FACS on day 4. Quadrants values are mean percentages (± SEM) obtained in each group (3 mice per group). (C) Activated OVA-specific CD4+ T cells infiltrating A20-OVA tumors at day 0 and 4 days later without therapy (no treatment) or after 4 days of i.t. low-dose immunomodulation (CpG plus αOX40/CTLA4). Results are presented as proportions of KJ1-26+CD25+ cells among total CD4+ T cells and absolute numbers of cells per 1,000 live cells (n = 3, *P < 0.05 at day 4). (D) DO11.10 mice (n = 5 per group) were challenged with 5 × 106 A20-OVA tumor cells s.c. Seven days later, one group received i.t. CpG plus αOX40/CTLA4 as described before. Infiltrating CD4+ T cells of A20-OVA tumors were analyzed by FACS for CD25 surface expression and FOXP3 intracellular expression. *P < 0.05. (E) Tumor-infiltrating CD4+FOXP3+ T cells within injected or uninjected A20-OVA tumors in WT mice on day 4 of therapy (n = 3 per group, *P < 0.05). (F) Effect of therapy on tumor-infiltrating tumor-specific Tregs (as defined by CD3+CD4+CD25+OX40+FOXP3+ cells) in injected A20 tumors of WT mice on day 4 of therapy (*P < 0.0001). The ratio of Teffs (CD3+CD4+CD25+OX40–FOXP3–) over tumor-specific Tregs (CD3+CD4+CD25+OX40+FOXP3+) is also displayed (†P = 0.01). Mean ± SEM.