Immune Cell Depletion for Tumor Therapy

Cellular subsets and cytokines were depleted by intraperitoneally administering depleting antibodies (BioXCell) beginning 1 d before therapy as we previously reported (Moynihan et al., 2016 (link)): CD8 T cells with anti-CD8-α (clone 2.43, 400 μg every 3 days), CD4 T cells with anti-CD4 (clone GK1.5, 400 μg every 3 days), NK cells with anti-NK1.1 (clone PK136, 400 μg every 3 days), neutrophils with anti-Gr-1 (clone RB6–8C5, 400 μg every 2 days), macrophages with anti-F4/80 (clone CI:A3–1, 200 μg every day) (Lin et al., 2017 (link)), IFN-γ with anti- IFN-γ (clone XT3.11, 200 μg every 3 days), TNF-α with anti-TNF-α (clone XMG1.2, 500 μg every 2 days) and CXCL9 with anti-CXCL9 (clone MIG-2F5.5, 300 μg every 2 days). VEGFR2 was blocked by anti-VEGFR2 (clone DC101, 500 μg every 3 days). Apoptosis of intratumoral T cells were induced with anti-CD3ε F(ab’)2 (clone 145–2C11, 50 μg for intratumoral injection or 100 μg for systematic i.p. injection every day) (Besançon et al., 2017 (link)) to avoid toxicity associated with full anti-CD3 antibodies in treated mice (data not shown). Cellular depletions of CD3⁺ T cells, CD8⁺ T cells, CD4⁺ T cells, neutrophils, macrophages and NK cells were confirmed by flow cytometry of PBMCs (Figures S3A and S4A).