Graphical Abstract Highlights d CD19 + EVs through CD39 and CD73 hydrolyze ATP from tumor cells into adenosine d CD19 + EVs blunt post-chemotherapeutic CD8 T cell responses via adenosine d Tumor B cells produce more EVs by enhancing HIF-1a-mediated Rab27a transcription d IEBVs-Rab27a siRNA is a potential tool for improving chemotherapeutic effect SUMMARY Systemic immunosuppression greatly affects the chemotherapeutic antitumor effect. Here, we showed that CD19 + extracellular vesicles (EVs) from B cells through CD39 and CD73 vesicle-incorporated proteins hydrolyzed ATP from chemotherapy-treated tumor cells into adenosine, thus impairing CD8 + T cell responses. Serum CD19 + EVs were increased in tumor-bearing mice and patients. Patients with fewer serum CD19 + EVs had a better prognosis after chemotherapy. Upregulated hypoxia-inducible factor-1a (HIF-1a) promoted B cells to release CD19 + EVs by inducing Rab27a mRNA transcription. Rab27a or HIF-1a deficiency in B cells inhibited CD19 + EV production and improved the chemotherapeutic antitumor effect. Silencing of Rab27a in B cells by inactivated Epstein-Barr viruses carrying Rab27a siRNA greatly improved chemotherapeutic efficacy in humanized immunocompromised NOD Prkdc scid Il2rg À/À mice. Thus, decreasing CD19 + EVs holds high potential to improve the chemotherapeutic antitumor effect.

Exosomes derived from heat-stressed tumour cells (HS-TEXs), which contain abundant heat shock protein (HSP) 70, strongly induce antitumour immune responses. HSP70-induced interleukin (IL)-6 promotes IL-17 expression and causes rejection of established prostate tumours. However, it remains unclear whether HS-TEXs exhibit antitumour effects by converting regulatory T cells (T ) into T helper type 17 (Th17) cells. In this study, we found that compared with TEXs, HS-TEXs were more potent in stimulating secretion of IL-6 from dendritic cells. In vitro, IL-6 blocked tumour cell-derived transforming growth factor beta 1-induced T differentiation and promoted Th17 cell differentiation. HS-TEXs exerted strong antitumour effects, converting T into Th17 cells with high efficiency, a process that was entirely dependent upon IL-6. Neutralization of IL-17 completely abolished the antitumour effect of TEXs, but only partially inhibited that of HS-TEXs. In addition, we found higher levels of IL-6 and IL-17 in serum from tumour patients treated with hyperthermia, and an increase in Th17 cells and a decrease in T was detected in peripheral blood mononuclear cells isolated from these patients after hyperthermia. Therefore, our results demonstrate that HS-TEXs possess a powerful capacity to convert immunosuppressive T into Th17 cells via IL-6, which contributes to their potent antitumour effect.

We have previously demonstrated that exosomes from dendritic cells (DCs) secreting TGF-β1 (sTGF-β1-EXOs) delay the development of murine inflammatory bowel disease (IBD). In this study, we isolated exosomes from DCs expressing membrane-associated TGF-β1 (mTGF-β1-EXOs) and found mTGF-β1-EXOs had more potent immunosuppressive activity than sTGF-β1-EXOs in vitro. Treatment of mice with mTGF-β1-EXOs inhibited the development and progression of myelin oligodendrocyte glycoprotein (MOG)peptide-induced EAE even after disease onset. Treatment of mice with mTGF-β1-EXOs also impaired Ag-specific Th1 and IL-17 responses, but promoted IL-10 responses ex vivo. Treatment with mTGF-β1-EXOs decreased the frequency of Th17 cells in EAE mice, which might be associated with the down-regulation of the p38, ERK, Stat3, and NF-κB activation and IL-6 expression in DCs. Treatment with mTGF-β1-EXOs maintained the regulatory capacity of Treg cells, and adoptive transfer of CD4 + Foxp3 + Treg cells from mTGF-β1-EXO-treated EAE mice dramatically prevented the development of EAE in the recipients. Moreover, treatment with mTGF-β1-EXOs from C57BL/6 mice effectively prevented and inhibited proteolipid protein (PLP) peptide-induced EAE in BALB/c mice. These results indicate that mTGF-β1-EXOs possess powerful immunosuppressive ability and can effectively inhibit the development and progression of EAE in different strains of mice.Keywords: Autoimmune diseases r Exosomes r TGF-β1 r Th17 r Treg cells IntroductionDCs are unique professional APCs and important for the initiation and regulation of immune response [1,2]. Immature DCs have lower levels of co-stimulatory molecules and usually Correspondence: Dr. Zhijian Cai e-mail: caizj@zju.edu.cn; jlwang@zju.edu.cn induce Ag-specific T-cell anergy [3]. TGF-β1 is a negative regulator of pro-inflammatory immune responses. We previously found that systemic administration of TGF-β1 gene-modified immature DCs delayed the development of dextran sulfate sodiuminduced murine inflammatory bowel disease (IBD) [4]. Therefore, * These authors contributed equally to this work. * * These authors share senior co-authorship.C 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.eji-journal.eu 2462 Lei Yu et al. Eur. J. Immunol. 2013. 43: 2461-2472 TGF-β1 may modify DC development toward a regulatory phenotype, inhibiting inflammation. Exosomes, released by almost all types of cells, are small lipid bilayer vesicles with a size of 50-100 nm. They are formed by membrane budding into the lumen of an endocytic compartment, leading to the formation of multivesicular bodies. Fusion of multivesicular bodies to plasma membrane leads to the extracellular release of exosomes [5,6]. Exosomes from DCs transfected with vIL-10, FasL, or IL-4 gene inhibit delayed-type hypersensitivity and collagen-induced murine arthritis [7,8]. These results indicate that exosomes can be effective vehicles to carry immunoregulatory molecules for the treatment of autoimmune diseases.Ag-specific Th1 and Th17 cells are crucial for the development of...

Our study indicated that heat stress increased the quantity of doxorubicin-containing exosomes from tumour cells, and enhanced the anti-tumour effect of exosomes from the doxorubicin-treated tumour cells. Our findings may aid in designing new strategies for cancer therapy by combination of chemotherapy and hyperthermia.

AMR, especially that involving multidrug-resistant organisms (MDROs), is recognized as a global threat to human health; AMR renders infections increasingly difficult to treat, constituting an enormous economic burden and producing tremendous negative impacts on patient morbidity and mortality rates. There are many surveillance programs in the world to address AMR profiles and MDRO prevalence in humans.