CAR-T cell-mediated depletion of immunosuppressive tumor-associated macrophages promotes endogenous antitumor immunity and augments adoptive immunotherapy

Alba Rodriguez-Garcia, Rachel C. Lynn, Mathilde Poussin, Monika A. Eiva, Lauren C. Shaw, Roddy S. O’Connor, Nicholas G. Minutolo, Victoria Casado-Medrano, Gonzalo Lopez, Takami Matsuyama, Daniel J. Powell

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

The immunosuppressive tumor microenvironment (TME) represents a major barrier for effective immunotherapy. Tumor-associated macrophages (TAMs) are highly heterogeneous and plastic cell components of the TME which can either promote tumor progression (M2-like) or boost antitumor immunity (M1-like). Here, we demonstrate that a subset of TAMs that express folate receptor β (FRβ) possess an immunosuppressive M2-like profile. In syngeneic tumor mouse models, chimeric antigen receptor (CAR)-T cell-mediated selective elimination of FRβ+ TAMs in the TME results in an enrichment of pro-inflammatory monocytes, an influx of endogenous tumor-specific CD8+ T cells, delayed tumor progression, and prolonged survival. Preconditioning of the TME with FRβ-specific CAR-T cells also improves the effectiveness of tumor-directed anti-mesothelin CAR-T cells, while simultaneous co-administration of both CAR products does not. These results highlight the pro-tumor role of FRβ+ TAMs in the TME and the therapeutic implications of TAM-depleting agents as preparative adjuncts to conventional immunotherapies that directly target tumor antigens.

Original languageEnglish
Article number877
JournalNature Communications
Volume12
Issue number1
DOIs
StatePublished - 1 Dec 2021

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