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Abstract As antigen-presenting cells (APC), B cells exert a variety of immune regulatory functions mainly by presenting antigens, triggering immune response, and producing antibodies for immune regulation. Regulatory B cells (Bregs) are special subpopulations of B cells with immune-regulating or immune-suppressing properties and play a role in peripheral tolerance. Bregs suppress immune response through inhibiting the differentiation of dendritic cells (DCs), suppressing the proliferation of helper T1(TH1) cells and helper T17 (TH17) cells, inducing the differentiation of fork head transcription factor p3 positive regulatory T cells (FoxP3+ Tregs). Different subsets of Bregs have distinct phenotypes and markers. Different subsets of Bregs participate in immune modulation by different ways. The absence or loss of Bregs exacerbates the severity of many disease such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and graft-versus-host-disease (GVHD). Bregs are also involved in tumor immunosuppressive effect and inhibit the antitumor immune process. In this article, we review the research advances of Bregs in autoimmune diseases, GVHD and tumor. Highlights • Previous studies have shown that regulatory B cells play important roles in inflammatory diseases and tumor. • There is no systematic review of the role of regulatory B cells in inflammatory diseases and tumor. • In this paper, the role of regulatory B cells in inflammatory diseases and tumors is systematically reviewed. • This article provides researchers with the latest systematic research of regulatory B cells. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) 'pulsed' with an appropriate antigen may elicit an antitumour immune response in mouse models. However, while attempting to develop a DC immunotherapy protocol for the treatment of breast cancer based on the tumour-associated MUC1 glycoforms, we found that unpulsed DCs can affect tumour growth. Protection from RMA-MUC1 tumour challenge was achieved in C57Bl/6 MUC1 transgenic mice by immunising with syngeneic DCs pulsed with a MUC1 peptide. However, unpulsed DCs gave a similar level of protection, making it impossible to evaluate the effect of immunisation of mice with DCs pulsed with the specific peptide. Balb/C mice could also be protected from tumour challenge by immunisation with unpulsed DCs prior to challenge with murine mammary tumour cells (410.4) or these cells transfected with MUC1 (E3). Protection was achieved with as few as three injections of 50,000 naïve DCs per mouse per week, was not dependent on injection route, and was not specific to cell lines expressing human MUC1. However, the use of Rag2-knockout mice demonstrated that the adaptive immune response was required for tumour rejection. Injection of unpulsed DCs into mice bearing the E3 tumour slowed tumour growth. In vitro, production of IFN-gamma and IL-4 was increased in splenic cells isolated from mice immunised with DCs. Depleting CD4 T cells in vitro partially decreased cytokine production by splenocytes, but CD8 depletion had no effect. This paper shows that naïve syngeneic DCs may induce an antitumour immune response and has implications for DC immunotherapy preclinical and clinical trials. [ABSTRACT FROM AUTHOR]

Various forms of immunotherapy, such as checkpoint blockade immunotherapy, are proving to be effective at restoring T cell-mediated immune responses that can lead to marked and sustained clinical responses, but only in some patients and cancer types.sup.1-4. Patients and tumours may respond unpredictably to immunotherapy partly owing to heterogeneity of the immune composition and phenotypic profiles of tumour-infiltrating lymphocytes (TILs) within individual tumours and between patients.sup.5,6. Although there is evidence that tumour-mutation-derived neoantigen-specific T cells play a role in tumour control.sup.2,4,7-10, in most cases the antigen specificities of phenotypically diverse tumour-infiltrating T cells are largely unknown. Here we show that human lung and colorectal cancer CD8.sup.+ TILs can not only be specific for tumour antigens (for example, neoantigens), but also recognize a wide range of epitopes unrelated to cancer (such as those from Epstein-Barr virus, human cytomegalovirus or influenza virus). We found that these bystander CD8.sup.+ TILs have diverse phenotypes that overlap with tumour-specific cells, but lack CD39 expression. In colorectal and lung tumours, the absence of CD39 in CD8.sup.+ TILs defines populations that lack hallmarks of chronic antigen stimulation at the tumour site, supporting their classification as bystanders. Expression of CD39 varied markedly between patients, with some patients having predominantly CD39.sup.- CD8.sup.+ TILs. Furthermore, frequencies of CD39 expression among CD8.sup.+ TILs correlated with several important clinical parameters, such as the mutation status of lung tumour epidermal growth factor receptors. Our results demonstrate that not all tumour-infiltrating T cells are specific for tumour antigens, and suggest that measuring CD39 expression could be a straightforward way to quantify or isolate bystander T cells.Human lung and colorectal tumours contain a population of tumour-infiltrating lymphocytes that are specific for tumour-unrelated antigens and, unlike tumour-antigen-specific tumour-infiltrating lymphocytes, do not express CD39., Author(s): Yannick Simoni [sup.1] , Etienne Becht [sup.1] , Michael Fehlings [sup.1] [sup.2] , Chiew Yee Loh [sup.1] , Si-Lin Koo [sup.3] , Karen Wei Weng Teng [sup.1] , Joe [...]

In this issue of the JCI, Panigrahy et al. demonstrate that preoperative administration of the antiinflammatory drug ketorolac or specialized proresolving mediators (SPM) called resolvins increases disease-free survival rates and prevents metastasis after surgery and chemotherapy in mouse models of cancer. The antitumor response was partially mediated by tumor- specific T cell immunity and immunological memory., When treatment also promotes disease A century after Virchow hypothesized the association between inflammation and cancer, it is becoming evident that inflammatory mediators lead to cancer progression and metastasis (1). [...]