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PD-1 Expression by Tumour-Associated Macrophages Inhibits Phagocytosis and Tumour Immunity

Sydney R Gordon, Roy L Maute, Ben W Dulken, Gregor Hutter, Benson M George, Melissa N McCracken, Rohit Gupta, Jonathan M Tsai, Rahul Sinha, Daniel Corey, Aaron M Ring, Andrew J Connolly, Irving L Weissman

Nature. 2017 May 25;545(7655):495-499.

PMID: 28514441

Abstract:

Programmed cell death protein 1 (PD-1) is an immune checkpoint receptor that is upregulated on activated T cells for the induction of immune tolerance. Tumour cells frequently overexpress the ligand for PD-1, programmed cell death ligand 1 (PD-L1), facilitating their escape from the immune system. Monoclonal antibodies that block the interaction between PD-1 and PD-L1, by binding to either the ligand or receptor, have shown notable clinical efficacy in patients with a variety of cancers, including melanoma, colorectal cancer, non-small-cell lung cancer and Hodgkin's lymphoma. Although it is well established that PD-1-PD-L1 blockade activates T cells, little is known about the role that this pathway may have in tumour-associated macrophages (TAMs). Here we show that both mouse and human TAMs express PD-1. TAM PD-1 expression increases over time in mouse models of cancer and with increasing disease stage in primary human cancers. TAM PD-1 expression correlates negatively with phagocytic potency against tumour cells, and blockade of PD-1-PD-L1 in vivo increases macrophage phagocytosis, reduces tumour growth and lengthens the survival of mice in mouse models of cancer in a macrophage-dependent fashion. This suggests that PD-1-PD-L1 therapies may also function through a direct effect on macrophages, with substantial implications for the treatment of cancer with these agents.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
IAR4248418 CD274 human CD274 human Price
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