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Enriched circulating and tumor-resident TGF-β+ regulatory B cells in patients with melanoma promote FOXP3+ Tregs

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Article number2104426
Pages (from-to)2104426
Issue number1
Accepted/In press18 Jul 2022
Published28 Jul 2022

Bibliographical note

Funding Information: The authors acknowledge support by the Cancer Research UK King’s Health Partners Centre at King’s College London (C604/A25135); the Guy’s and St Thomas’ Foundation Trust Charity, Melanoma Special Fund (SPF573); CR UK//NIHR in England/DoH for Scotland, Wales and Northern Ireland Experimental Cancer Medicine Centre (C10355/A15587); Cancer Research UK (C30122/A11527; C30122/A15774); the Medical Research Council (MR/L023091/1). This research was supported by the National Institute for Health and Care Research (NIHR) Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London and the NIHR Clinical Research Facility (NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London. IS-BRC-1215-20006). The authors are solely responsible for study design, data collection, analysis, decision to publish, and preparation of the manuscript. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care. We thank Dr Sara Lombardi (Oncology Haematology Clinical Trials, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom) in collecting and making available samples used in the generation of this publication. We also acknowledge the Biomedical Research Centre Immune Monitoring Core Facility team at Guy’s and St Thomas’ NHS Foundation Trust for assistance. Publisher Copyright: © 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.


King's Authors


B cells are emerging as key players of anti-tumor adaptive immune responses. We investigated regulatory and pro-inflammatory cytokine-expressing B cells in patients with melanoma by flow cytometric intracellular cytokine, CyTOF, transcriptomic, immunofluorescence, single-cell RNA-seq, and B:T cell co-culture analyses. We found enhanced circulating regulatory (TGF-β + and PD-L1 +) and reduced pro-inflammatory TNF-α + B cell populations in patients compared with healthy volunteers (HVs), including lower IFN-γ +:IL-4 + and higher TGF-β +:TNF-α + B cell ratios in patients. TGF-β-expressing B cells in the melanoma tumor microenvironment assembled in clusters and interacted with T cells via lymphoid recruitment (SELL, CXCL13, CCL4, CD74) signals and with Tregs via CD47:SIRP-γ, and FOXP3-promoting Galectin-9:CD44. While reduced in tumors compared to blood, TNF-α-expressing B cells engaged in crosstalk with Tregs via TNF-α signaling and the ICOS/ICOSL axis. Patient-derived B cells promoted FOXP3 + Treg differentiation in a TGF-β-dependent manner, while sustaining expression of IFN-γ and TNF-α by autologous T-helper cells and promoting T-helper cell proliferation ex vivo, an effect further enhanced with anti-PD-1 checkpoint blockade. Our findings reveal cytokine-expressing B cell compartments skewed toward regulatory phenotypes in patient circulation and melanoma lesions, intratumor spatial localization, and bidirectional crosstalk between B and T cell subsets with immunosuppressive attributes.

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