Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade

Abstract Emerging evidence suggests a role for radiation in eliciting anti‐tumour immunity. We aimed to investigate the role of macrophages in modulating the immune response to radiation. Irradiation to murine tumours generated from colorectal (MC38) and pancreatic (KPC) cell lines induced colony‐st...

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Main Authors: Keaton I Jones, Jiske Tiersma, Arseniy E Yuzhalin, Alex N Gordon‐Weeks, Jon Buzzelli, Jae Hong Im, Ruth J Muschel
Format: Article
Language:English
Published: Springer Nature 2018-11-01
Series:EMBO Molecular Medicine
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Online Access:https://doi.org/10.15252/emmm.201809342
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author Keaton I Jones
Jiske Tiersma
Arseniy E Yuzhalin
Alex N Gordon‐Weeks
Jon Buzzelli
Jae Hong Im
Ruth J Muschel
author_facet Keaton I Jones
Jiske Tiersma
Arseniy E Yuzhalin
Alex N Gordon‐Weeks
Jon Buzzelli
Jae Hong Im
Ruth J Muschel
author_sort Keaton I Jones
collection DOAJ
description Abstract Emerging evidence suggests a role for radiation in eliciting anti‐tumour immunity. We aimed to investigate the role of macrophages in modulating the immune response to radiation. Irradiation to murine tumours generated from colorectal (MC38) and pancreatic (KPC) cell lines induced colony‐stimulating factor 1 (CSF‐1). Coincident with the elevation in CSF‐1, macrophages increased in tumours, peaking 5 days following irradiation. These tumour‐associated macrophages (TAMs) were skewed towards an immunosuppressive phenotype. Macrophage depletion via anti‐CSF (aCSF) reduced macrophage numbers, yet only achieved tumour growth delay when combined with radiation. The tumour growth delay from aCSF after radiation was abrogated by depletion of CD8 T cells. There was enhanced recognition of tumour cell antigens by T cells isolated from irradiated tumours, consistent with increased antigen priming. The addition of anti‐PD‐L1 (aPD‐L1) resulted in improved tumour suppression and even regression in some tumours. In summary, we show that adaptive immunity induced by radiation is limited by the recruitment of highly immunosuppressive macrophages. Macrophage depletion partly reduced immunosuppression, but additional treatment with anti‐PD‐L1 was required to achieve tumour regression.
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spelling doaj-art-be307394213f42598b2d3a0581459ea32025-08-20T03:06:00ZengSpringer NatureEMBO Molecular Medicine1757-46761757-46842018-11-01101211610.15252/emmm.201809342Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockadeKeaton I Jones0Jiske Tiersma1Arseniy E Yuzhalin2Alex N Gordon‐Weeks3Jon Buzzelli4Jae Hong Im5Ruth J Muschel6Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Churchill Hospital, University of OxfordDepartment of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Churchill Hospital, University of OxfordDepartment of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Churchill Hospital, University of OxfordNuffield Department of Surgical Sciences, John Radcliffe Hospital, University of OxfordDepartment of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Churchill Hospital, University of OxfordDepartment of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Churchill Hospital, University of OxfordDepartment of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, Churchill Hospital, University of OxfordAbstract Emerging evidence suggests a role for radiation in eliciting anti‐tumour immunity. We aimed to investigate the role of macrophages in modulating the immune response to radiation. Irradiation to murine tumours generated from colorectal (MC38) and pancreatic (KPC) cell lines induced colony‐stimulating factor 1 (CSF‐1). Coincident with the elevation in CSF‐1, macrophages increased in tumours, peaking 5 days following irradiation. These tumour‐associated macrophages (TAMs) were skewed towards an immunosuppressive phenotype. Macrophage depletion via anti‐CSF (aCSF) reduced macrophage numbers, yet only achieved tumour growth delay when combined with radiation. The tumour growth delay from aCSF after radiation was abrogated by depletion of CD8 T cells. There was enhanced recognition of tumour cell antigens by T cells isolated from irradiated tumours, consistent with increased antigen priming. The addition of anti‐PD‐L1 (aPD‐L1) resulted in improved tumour suppression and even regression in some tumours. In summary, we show that adaptive immunity induced by radiation is limited by the recruitment of highly immunosuppressive macrophages. Macrophage depletion partly reduced immunosuppression, but additional treatment with anti‐PD‐L1 was required to achieve tumour regression.https://doi.org/10.15252/emmm.201809342immunosuppressionimmunotherapymacrophageradiation
spellingShingle Keaton I Jones
Jiske Tiersma
Arseniy E Yuzhalin
Alex N Gordon‐Weeks
Jon Buzzelli
Jae Hong Im
Ruth J Muschel
Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
EMBO Molecular Medicine
immunosuppression
immunotherapy
macrophage
radiation
title Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
title_full Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
title_fullStr Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
title_full_unstemmed Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
title_short Radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
title_sort radiation combined with macrophage depletion promotes adaptive immunity and potentiates checkpoint blockade
topic immunosuppression
immunotherapy
macrophage
radiation
url https://doi.org/10.15252/emmm.201809342
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AT arseniyeyuzhalin radiationcombinedwithmacrophagedepletionpromotesadaptiveimmunityandpotentiatescheckpointblockade
AT alexngordonweeks radiationcombinedwithmacrophagedepletionpromotesadaptiveimmunityandpotentiatescheckpointblockade
AT jonbuzzelli radiationcombinedwithmacrophagedepletionpromotesadaptiveimmunityandpotentiatescheckpointblockade
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