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Microbes exert influence across the microbiome-gut-brain axis through neurotransmitter production, induction of host immunomodulators, or the release or induction of other microbial or host molecules. Here, we used mass spectrometry imaging (MSI), a label-free imaging tool, to map molecular changes in the gut and brain in germ-free, antibiotic-treated and control mice. We determined spatial distribution and relative quantification of neurotransmitters and their precursors in response to the microbiome. Using untargeted MSI, we detected a significant change in the levels of four identified small molecules in the brains of germ-free animals compared to controls. However, antibiotic treatment induced no significant changes in these same metabolites in the brain after 1 week of treatment. This work exemplifies the utility of MSI as a tool for the study of known and discovery of novel, mediators of microbiome-gut-brain axis communication.

Supplemental Figure S5. Effects of DMH1 on NK cells IFN-y production and killing capacity upon target cell engagement.

Natural killer (NK) cells are critical for innate tumor immunity due to their specialized ability to recognize and kill neoplastically transformed cells. However, NK cells require a specific set of cytokine-mediated signals to achieve optimal effector function. Th1-associated cytokines promote effector functions that are inhibited by the prototypic Th2 cytokine IL4 and the TGFβ superfamily members TGFβ1 and activin-A. Interestingly, the largest subgroup of the TGFβ superfamily are the bone morphogenetic proteins (BMP), but the effects of BMP signaling on NK cell effector functions have not been evaluated. Here, we demonstrate that blood-circulating NK cells express type I and II BMP receptors, BMP-2 and BMP-6 ligands, and phosphorylated isoforms of Smad-1/-5/-8, which mediate BMP family member signaling. In opposition to the inhibitory effects of TGFβ1 or activin-A, autocrine BMP signaling was supportive to NK cell function. Mechanistic investigations in cytokine and TLR-L–activated NK cells revealed that BMP signaling optimized IFNγ and global cytokine and chemokine production, phenotypic activation and proliferation, and autologous dendritic cell activation and target cytotoxicity. Collectively, our findings identify a novel auto-activatory pathway that is essential for optimal NK cell effector function, one that might be therapeutically manipulated to help eradicate tumors. Cancer Res; 74(18); 5019–31. ©2014 AACR.

The recent revolution in tissue-resident macrophage biology has resulted largely from murine studies performed in C57BL/6 mice. Here, using both C57BL/6 and BALB/c mice, we analyze immune cells in the pleural cavity. Unlike C57BL/6 mice, naive tissue-resident large-cavity macrophages (LCMs) of BALB/c mice failed to fully implement the tissue-residency program. Following infection with a pleural-dwelling nematode, these pre-existing differences were accentuated with LCM expansion occurring in C57BL/6, but not in BALB/c mice. While infection drove monocyte recruitment in both strains, only in C57BL/6 mice were monocytes able to efficiently integrate into the resident pool. Monocyte-to-macrophage conversion required both T cells and interleukin-4 receptor alpha (IL-4Rα) signaling. The transition to tissue residency altered macrophage function, and GATA6+ tissue-resident macrophages were required for host resistance to nematode infection. Therefore, during tissue nematode infection, T helper 2 (Th2) cells control the differentiation pathway of resident macrophages, which determines infection outcome.

Inflammatory conditions, including allergic asthma and conditions in which chronic low-grade inflammation is a risk factor, such as stress-related psychiatric disorders, are prevalent and are a significant cause of disability worldwide. Novel approaches for the prevention and treatment of these disorders are needed. One approach is the use of immunoregulatory microorganisms, such as Mycobacterium vaccae NCTC 11659, which have anti-inflammatory, immunoregulatory, and stress-resilience properties. However, little is known about how M. vaccae NCTC 11659 affects specific immune cell targets, including monocytes, which can traffic to peripheral organs and the central nervous system and differentiate into monocyte-derived macrophages that, in turn, can drive inflammation and neuroinflammation. In this study, we investigated the effects of M. vaccae NCTC 11659 and subsequent lipopolysaccharide (LPS) challenge on gene expression in human monocyte-derived macrophages. THP-1 monocytes were differentiated into macrophages, exposed to M. vaccae NCTC 11659 (0, 10, 30, 100, 300 µg/mL), then, 24 h later, challenged with LPS (0, 0.5, 2.5, 250 ng/mL), and assessed for gene expression 24 h following challenge with LPS. Exposure to M. vaccae NCTC 11659 prior to challenge with higher concentrations of LPS (250 ng/mL) polarized human monocyte-derived macrophages with decreased IL12A, IL12B, and IL23A expression relative to IL10 and TGFB1 mRNA expression. These data identify human monocyte-derived macrophages as a direct target of M. vaccae NCTC 11659 and support the development of M. vaccae NCTC 11659 as a potential intervention to prevent stress-induced inflammation and neuroinflammation implicated in the etiology and pathophysiology of inflammatory conditions and stress-related psychiatric disorders.

An important aspect of immunotherapy is the ability of dendritic cells (DCs) to prime T cell immunity, an approach that has yielded promising results in some early phase clinical trials. However, novel approaches are required to improve DC therapeutic efficacy by enhancing their uptake of, and activation by, disease relevant antigens. The carbon nano-material graphene oxide (GO) may provide a unique way to deliver antigen to innate immune cells and modify their ability to initiate effective adaptive immune responses. We have assessed whether GO of various lateral sizes affects DC activation and function in vitro and in vivo, including their ability to take up, process and present the well-defined model antigen ovalbumin (OVA). We have found that GO flakes are internalised by DCs, while having minimal effect on their viability, activation phenotype or cytokine production. Although adsorption of OVA protein to either small or large GO flakes promoted its uptake into DCs, large GO interfered with OVA processing. In terms of modulation of DC function, delivery of OVA via small GO flakes significantly enhanced DC ability to induce proliferation of OVA-specific CD4 T cells, promoting granzyme B secretion in vitro. On the other hand, delivery of OVA via large GO flakes augmented DC ability to induce proliferation of OVA-specific CD8 T cells, and their production of IFN-γ and granzyme B. Together, these data demonstrate the capacity of GO of different lateral dimensions to act as a promising delivery platform for DC modulation of distinct facets of the adaptive immune response, information that could be exploited for future development of targeted immunotherapies., his work was supported by the Engineering and Physical Sciences Research Council (EPSRC) under the 2D-Health Programme Grant [EP/P00119X/1]. The Nanomedicine Group at ICN2 is partially supported by the CERCA programme, Generalitat de Catalunya, and the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, grant no. SEV-2017-0706).

Background and Objectives: \ud Gastrectomy for gastric cancer is associated with significant infective postoperative complications. C-reactive protein (CRP) is a useful biomarker in the early detection of infective complications following major abdominal surgery. This single-centre retrospective study aimed to determine the relationship between postoperative CRP levels and development of postoperative infective complications after gastrectomy.\ud \ud Methods: \ud Daily postoperative CRP levels were analyzed to determine a CRP threshold associated with infective complications. ROC curve analysis was used to determine which postoperative day (POD) gave the optimal cutoff. Multivariate analysis was performed to determine significant factors associated with complications.\ud \ud Results: \ud One hundred and forty-four patients were included. A total of 61 patients (42%) had at least one infective complication. A CRP level of 220 mg/L was associated with the highest AUC (0.765) with a sensitivity of 70% and specificity of 76% (positive predictive value, 67%; negative predictive value, 78%). More patients with a CRP > 220 mg/L on POD 3 developed infective complications (67% vs. 21%, p

Plasmacytoid dendritic cells (pDCs) are potent producers of type I IFN (IFN-I) during viral infection and respond to IFN-I in a positive feedback loop that promotes their function. IFN-I shapes dendritic cell responses during helminth infection, impacting their ability to support Th2 responses. However, the role of pDCs in type 2 inflammation is unclear. Previous studies have shown that pDCs are dispensable for hepatic or splenic Th2 responses during the early stages of murine infection with the trematode Schistosoma mansoni at the onset of parasite egg laying. However, during S. mansoni infection, an ongoing Th2 response against mature parasite eggs is required to protect the liver and intestine from acute damage and how pDCs participate in immune responses to eggs and adult worms in various tissues beyond acute infection remains unclear. We now show that pDCs are required for optimal Th2 cytokine production in response to S. mansoni eggs in the intestinal-draining mesenteric lymph nodes throughout infection and for egg-specific IFN-γ at later time points of infection. Further, pDC depletion at chronic stages of infection led to increased hepatic and splenic pathology as well as abrogated Th2 cell cytokine production and activation in the liver. In vitro, mesenteric lymph node pDCs supported Th2 cell responses from infection-experienced CD4+ T cells, a process dependent on pDC IFN-I responsiveness, yet independent of Ag. Together, these data highlight a previously unappreciated role for pDCs and IFN-I in maintaining and reinforcing type 2 immunity in the lymph nodes and inflamed tissue during helminth infection.

The murine serous cavities contain a rare and enigmatic population of short-lived F4/80 loMHCII + macrophages but what regulates their development, survival, and fate is unclear. Here, we show that mature F4/80 loMHCII + peritoneal macrophages arise after birth, but that this occurs largely independently of colonization by microbiota. Rather, microbiota specifically regulate development of a subpopulation of CD11c + cells that express the immunoregulatory cytokine RELM-α, are reliant on the transcription factor EGR2, and develop independently of the growth factor CSF1. Furthermore, we demonstrate that intrinsic expression of RELM-α, a signature marker shared by CD11c + and CD11c – F4/80 loMHCII + cavity macrophages, regulates survival and differentiation of these cells in the peritoneal cavity in a sex-specific manner. Thus, we identify a previously unappreciated diversity in serous cavity F4/80 loMHCII + macrophages that is regulated by microbiota, and describe a novel sex and site-specific function for RELM-α in regulating macrophage endurance that reveals the unique survival challenge presented to monocyte-derived macrophages by the female peritoneal environment.

Introduction: Novel cancer immunotherapies are urgently needed due to a lack of definitive treatments, as well as toxicity and cost of current therapies. 2-dimensional carbon graphene oxide (GO) nanomaterials provide a large surface area, high protein loading efficiency and good biocompatibility, as well as being inexpensive. Given these properties, we investigated whether and how GO could be an effective antigen delivery system for targeted cancer immunotherapies. Methods: GO was non-covalently complexed with the model antigen ovalbumin peptide (OVA257-264) and the immunostimulant and toll-like receptor 3 agonist polyinosinic:polycytidylic acid (Poly (I:C)). We examined innate and adaptive immune responses after subcutaneous injection of GO complexes by histology and flow cytometry. Results: We found that GO without Poly (I:C) had a very limited immunogenic potential. In contrast, GO complexed with Poly (I:C) significantly increased immune cell recruitment to the injection site, and enhanced activation and migration of dendritic cell subsets (cDC1s and cDC2s) in skin-draining lymph nodes 24 hours after injection. Additionally, we found that GO complexed with Poly (I:C) dramatically enhanced OVA-specific CD8+ T cell expansion and cytotoxic potential in both spleen and skin-draining lymph nodes 7 days after subcutaneous complex administration to mice which had previously been injected intravenously with traceable, OVA-specific (OT-I) CD8+ T cells. Conclusion: Our results have revealed the immunomodulatory potential of GO when complexed with Poly (I:C) by attracting immune cells to the injection site and augmenting antigen-specific cytotoxic responses both locally and systemically. Ongoing work is determining the anti-tumor potential of this approach, and potential mechanisms by which GO complexes might limit tumor progression. Citation Format: Sorayut Chattrakarn, Grace Mallett, Helen Parker, Neus Lozano, Kostas Kostarelos, Andrew S. MacDonald. Assessment of the potential of graphene oxide as an antigen delivery platform for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB334.

The murine serous cavities contain a rare and enigmatic population of short-lived F4/80

Antigen (Ag)-presenting cells (APC) instruct CD4+ helper T (Th) cell responses, but it is unclear whether different APC subsets contribute uniquely in determining Th differentiation in pathogen-specific settings. Here, we use skin-relevant, fluorescently-labeled bacterial, helminth or fungal pathogens to track and characterize the APC populations that drive Th responses in vivo. All pathogens are taken up by a population of IRF4+ dermal migratory dendritic cells (migDC2) that similarly upregulate surface co-stimulatory molecules but express pathogen-specific cytokine and chemokine transcripts. Depletion of migDC2 reduces the amount of Ag in lymph node and the development of IFNγ, IL-4 and IL-17A responses without gain of other cytokine responses. Ag+ monocytes are an essential source of IL-12 for both innate and adaptive IFNγ production, and inhibit follicular Th cell development. Our results thus suggest that Th cell differentiation does not require specialized APC subsets, but is driven by inducible and pathogen-specific transcriptional programs in Ag+ migDC2 and monocytes., Antigen presenting cells induce CD4+ T helper (Th) differentiation upon pathogen encounters. Here the authors use fluorescently-labeled bacteria, helminth and fungi to track and describe the functions of IRF4+ migratory type 2 dendritic cells and monocytes in the specific induction of Th1, Th2 or Th17 responses following skin inoculation.

The OX40-OX40L pathway provides crucial co-stimulatory signals for CD4 T cell responses, however the precise cellular interactions critical for OX40L provision in vivo and when these occur, remains unclear. Here, we demonstrate that provision of OX40L by dendritic cells (DCs), but not T cells, B cells nor group 3 innate lymphoid cells (ILC3s), is critical specifically for the effector Th1 response to an acute systemic infection with Listeria monocytogenes (Lm). OX40L expression by DCs is regulated by cross-talk with NK cells, with IFNγ signalling to the DC to enhance OX40L in a mechanism conserved in both mouse and human DCs. Strikingly, DC expression of OX40L is redundant in a chronic intestinal Th1 response and expression by ILC3s is necessary. Collectively these data reveal tissue specific compartmentalisation of the cellular provision of OX40L and define a mechanism controlling DC expression of OX40L in vivo., The OX40-OX40L axis is a crucial component of the costimulatory requirement of CD4 T cell responses. Here, the authors show context and cell type specific expression of OX40L for driving Th1 cell generation during acute and chronic models of infection.

T-bet is the lineage-specifying transcription factor for CD4+ T helper type 1 (TH 1) cells. T-bet has also been found in other CD4+ T cell subsets, including TH 17 cells and Treg, where it modulates their functional characteristics. However, we lack information on when and where T-bet is expressed during T cell differentiation and how this impacts T cell differentiation and function. To address this, we traced the ontogeny of T-bet-expressing cells using a fluorescent fate-mapping mouse line. We demonstrate that T-bet is expressed in a subset of CD4+ T cells that have naïve cell surface markers and a naïve cell transcriptional profile and that this novel cell population is phenotypically and functionally distinct from previously described populations of naïve and memory CD4+ T cells. Naïve-like T-bet-experienced cells are polarised to the TH 1 lineage, predisposed to produce IFNγ upon cell activation, and resist repolarisation to other lineages in vitro and in vivo. These results demonstrate that lineage-specifying factors can polarise T cells in the absence of canonical markers of T cell activation and that this has an impact on the subsequent T helper response. This article is protected by copyright. All rights reserved.

The last decade has been somewhat of a renaissance period for the field of macrophage biology. This renewed interest, combined with the advent of new technologies and development of novel model systems to assess different facets of macrophage biology, has led to major advances in our understanding of the diverse roles macrophages play in health, inflammation, infection and repair, and the dominance of tissue environments in influencing all of these areas. Here, we discuss recent developments in our understanding of lung macrophage heterogeneity, ontogeny, metabolism and function in the context of health and disease, and highlight core conceptual advances and key unanswered questions that we believe should be focus of work in the coming years.

The recent revolution in tissue-resident macrophage biology has resulted largely from murine studies performed in the C57BL/6 strain. Here, we provide a comprehensive analysis of immune cells in the pleural cavity using both C57BL/6 and BALB/c mice. Unlike C57BL/6 mice, naïve tissue-resident Large Cavity Macrophages (LCM) of BALB/c mice failed to fully implement the tissue residency program. Following infection with a pleural-dwelling nematode these pre-existing differences were accentuated with LCM expansion occurring in C57BL/6 but not BALB/c mice. While infection drove monocyte recruitment in both strains, only in C57BL/6 mice were monocytes able to efficiently integrate into the resident pool. Monocyte to macrophage conversion required both T cells and IL-4Rα signalling. Host genetics are therefore a key influence on tissue resident macrophage biology, and during nematode infection Th2 cells control the differentiation pathway of tissue resident macrophages.Graphical Abstract

T-bet is the lineage-specifying transcription factor for CD4

Aim Effective, high-quality patient handovers between the surgical team are essential for safe transfer of responsibility for patient care whilst ensuring continued patient-safety and supporting good clinical governance. Weekend handovers provide a particular challenge, with error potential, when patients are cared for by multiple different healthcare professionals. This project aimed to improve the documentation of the weekend handover for the surgical inpatients of a busy UK teaching hospital. Method Quality Improvement project performed within a single General Surgical department between August and October 2020. An initial casenote audit on 3 consecutive Fridays compared available handover information against RCS guidance. A comprehensive surgical weekend handover sticker was designed and all members of the surgical team educated in its use. Following sticker introduction, handover quality was similarly re-audited. **=p Results 138 inpatient records were evaluated in cycle 1 and 135 in cycle 2, with the proportion containing a weekend handover increased post-intervention (96 vs. 82%,p=0.0004). Handover quality improved following sticker introduction with more frequent documentation of: diagnosis (96 vs. 21%**); need for imaging review (94 vs. 29%**); intravenous fluid plan (84 vs. 21%**); blood test requirements (94 vs. 24%**); mode of nutrition (90 vs. 24%**); antibiotics (90 vs. 30%**); drug monitoring (90 vs. 1%**); discharge planning (94 vs. 44%**) and escalation plan (87 vs. 0%**). Conclusion Introduction of a sticker has significantly improved the quality of documented handover available to the responsible on-call team. Future work will assess sticker impact on quality of care and clinical outcomes.

Aims Appendicectomy is one of the commonest emergency General Surgical operations performed. However, there exists minimal published literature exploring whether there are differences between males and females undergoing appendicectomy. This study aimed to investigate the demographics, pre-operative investigation, intra-operative findings and clinical outcomes between both genders having an emergency appendicectomy. Methods A multicentre retrospective cohort study of all patients who had an emergency appendicectomy within four UK hospitals between September 2019 and November 2020. Electronic records were interrogated and patients dichotomised by gender and the results compared. Results 559 emergency appendicectomies (315 (56.4%) male and 244 (43.6%) female patients) were included. Males undergoing appendicectomy were younger (median age: 33 vs 41 years, p Conclusions This study demonstrates that differences exist between males and females who have emergency appendicectomy in terms of age, use of pre-operative imaging and operative approach, however, clinical outcomes are similar.

Discovery of novel bacterial metabolites reveals an unprecedented role for the microbiome in gut-brain axis communication., Alterations to the gut microbiome are associated with various neurological diseases, yet evidence of causality and identity of microbiome-derived compounds that mediate gut-brain axis interaction remain elusive. Here, we identify two previously unknown bacterial metabolites 3-methyl-4-(trimethylammonio)butanoate and 4-(trimethylammonio)pentanoate, structural analogs of carnitine that are present in both gut and brain of specific pathogen–free mice but absent in germ-free mice. We demonstrate that these compounds are produced by anaerobic commensal bacteria from the family Lachnospiraceae (Clostridiales) family, colocalize with carnitine in brain white matter, and inhibit carnitine-mediated fatty acid oxidation in a murine cell culture model of central nervous system white matter. This is the first description of direct molecular inter-kingdom exchange between gut prokaryotes and mammalian brain cells, leading to inhibition of brain cell function.

BackgroundImmune defects in chronic pulmonary aspergillosis (CPA) are poorly characterized. We compared peripheral blood cytokine profiles in patients with CPA versus healthy controls and explored the relationship with disease severity.MethodsInterferon-gamma (IFNγ), interleukin (IL)-17, tumor necrosis factor-α, IL-6, IL-12, and IL-10 were measured after in vitro stimulation of whole blood with lipopolysaccharide (LPS), phytohemagglutinin, β-glucan, zymosan (ZYM), IL-12 or IL-18, and combinations. Clinical parameters and mortality were correlated with cytokine production.ResultsCytokine profiles were evaluated in 133 patients (57.1% male, mean age 61 years). In comparison to controls, patients with CPA had significantly reduced production of IFNγ in response to stimulation with β-glucan + IL-12 (312 vs 988 pg/mL), LPS + IL-12 (252 vs 1033 pg/mL), ZYM + IL-12 (996 vs 2347 pg/mL), and IL-18 + IL-12 (7193 vs 12 330 pg/mL). Age >60 (hazard ratio [HR], 1.71; 95% confidence interval [CI], 1.00–2.91; P = .05) and chronic obstructive pulmonary disease (HR, 1.69; 95% CI, 1.03–2.78; P = .039) were associated with worse survival, whereas high IFNγ production in response to beta-glucan + IL-12 stimulation (HR, 0.48; 95% CI, .25–0.92; P = .026) was associated with reduced mortality.ConclusionsPatients with CPA show impaired IFNγ production in peripheral blood in response to stimuli. Defective IFNγ production ability correlates with worse outcomes. Immunotherapy with IFNγ could be beneficial for patients showing impaired IFNγ production in CPA.

The helminth Schistosoma mansoni (S. mansoni) induces a network of regulatory immune cells, including interleukin (IL)-10-producing regulatory B (Breg) cells. However, the signals required for the development and activation of Breg cells are not well characterized. Recent reports suggest that helminths induce type I interferons (IFN-I), and that IFN-I drives the development of Breg cells in humans. We therefore assessed the role of IFN-I in the induction of Breg cells by S. mansoni. Mice chronically infected with S.mansoni or intravenously injected with S.mansoni soluble egg antigen (SEA) developed a systemic IFN-I signature. Recombinant IFNα enhanced IL-10 production by Breg cells stimulated with S. mansoni soluble egg antigen (SEA) in vitro, while not activating Breg cells by itself. IFN-I signalling also supported ex vivo IL-10 production by SEA-primed Breg cells but was dispensable for activation of S. mansoni egg-induced Breg cells in vivo. These data indicate that while IFN-I can serve as a co-activator for Breg cell IL-10 production, they are unlikely to participate in the development of Breg cells in response to S. mansoni eggs. This article is protected by copyright. All rights reserved.

Fine control of macrophage activation is needed to prevent inflammatory disease, particularly at barrier sites such as the lungs.However, the dominant mechanisms that regulate the activation of pulmonary macrophages during inflammation are poorly understood. We found that alveolar macrophages (AlvMs) were much less able to respond to the canonical type 2 cytokine IL-4, which underpins allergic disease and parasitic worm infections, than macrophages from lung tissue or the peritoneal cavity. We found that the hyporesponsiveness of AlvMs to IL-4 depended upon the lung environment but was independent of the host microbiota or the lung extracellular matrix components surfactant protein D (SP-D) and mucin 5b (Muc5b). AlvMs showedseverely dysregulated metabolism relative to that of cavity macrophages. After removal from the lungs, AlvMs regained responsiveness to IL-4 in a glycolysis-dependent manner. Thus, impaired glycolysis in the pulmonary niche regulates AlvM responsiveness during type 2 inflammation.

Schistosome infection is a major cause of global morbidity, particularly in sub-Saharan Africa. However, there is no effective vaccine for this major neglected tropical disease, and re-infection routinely occurs after chemotherapeutic treatment. Following invasion through the skin, larval schistosomula enter the circulatory system and migrate through the lung before maturing to adulthood in the mesenteric or urogenital vasculature. Eggs released from adult worms can become trapped in various tissues, with resultant inflammatory responses leading to hepato-splenic, intestinal, or urogenital disease – processes that have been extensively studied in recent years. In contrast, although lung pathology can occur in both the acute and chronic phases of schistosomiasis, the mechanisms underlying pulmonary disease are particularly poorly understood. In chronic infection, egg-mediated fibrosis and vascular destruction can lead to the formation of portosystemic shunts through which eggs can embolise to the lungs, where they can trigger granulomatous disease. Acute schistosomiasis, or Katayama syndrome, which is primarily evident in non-endemic individuals, occurs during pulmonary larval migration, maturation, and initial egg-production, often involving fever and a cough with an accompanying immune cell infiltrate into the lung. Importantly, lung migrating larvae are not just a cause of inflammation and pathology but are a key target for future vaccine design. However, vaccine efforts are hindered by a limited understanding of what constitutes a protective immune response to larvae. In this review, we explore the current understanding of pulmonary immune responses and inflammatory pathology in schistosomiasis, highlighting important unanswered questions and areas for future research.

IL-13 plays a key role during protective type 2 immune responses at mucosal sites, such as during infection with nematodes. However, dysregulation of IL-13 can also contribute to the pathogenesis of atopic and fibrotic diseases such as allergic asthma. Matrix remodelling is an important component of repair processes in the lung but also a hallmark of chronic conditions involving fibrosis. Hence, understanding the role of IL-13 in tissue remodelling has important clinical implications. Since IL-13 shares receptors and signalling pathways with IL-4, disentangling the relative contributions of these type 2 cytokines has been challenging. Additionally, little is known about the singular role of IL-13 following acute tissue injury. In this study, we used Nippostrongylus brasiliensis infection as a model of acute lung tissue damage comparing responses between WT and IL-13-deficient mice, in which IL-4 signalling is intact. Importantly, we found that IL-13 played a critical role in limiting tissue injury and haemorrhaging in the lung following infection. Through proteomic and transcriptomic profiling, we identified IL-13-dependent changes in matrix and associated regulators. We further showed that IL-13 is required for the induction of epithelial-derived type 2 effector molecules such as RELM-α and surfactant protein D. Pathway analyses predicted that IL-13 was heavily involved in the induction of cellular stress responses and regulation of lung epithelial cell differentiation by suppression of Foxa2 pathways. Thus, we propose that IL-13 has tissue-protective functions during lung injury and regulates epithelial cell responses during type 2 immunity in this acute setting.

The novel, highly contagious coronavirus SARS-CoV-2 spreads rapidly throughout the world, leading to a deadly pandemic of a predominantly respiratory illness called COVID-19. Safe and effective anti-SARS-CoV-2 vaccines are urgently needed. However, emerging immunological observations show hallmarks of significant immunopathological characteristics and dysfunctional immune responses in patients with COVID-19. Combined with existing knowledge about immune responses to other closely related and highly pathogenic coronaviruses, this could forebode significant challenges for vaccine development, including the risk of vaccine failure. Animal data from earlier coronavirus vaccine efforts indicate that elderly people, most at risk from severe COVID-19 disease, could be especially at risk from immunopathologic responses to novel coronavirus vaccines. Bacterial "new old friends" such as Bacille Calmette-Guérin (BCG) or Mycobacterium obuense have the ability to elevate basal systemic levels of type 1 cytokines and immune cells, correlating with increased protection against diverse and unrelated infectious agents, called "trained immunity." Here we describe dysfunctional immune responses induced by coronaviruses, representing potentially difficult to overcome obstacles to safe, effective vaccine development for COVID-19, and outline how trained immunity could help protect high risk populations through immunomodulation with BCG and other "new old friends."

Aims: Co-inhibitory receptors play a major role in controlling the Th1 response during blood-stage malaria. Whilst PD-1 is viewed as the dominant co-inhibitory receptor restricting T cell responses, the roles of other such receptors in coordinating Th1 cell activity during malaria are poorly understood.Methods and Results: Here we show that the co-inhibitory receptor Tim-3 is expressed on splenic antigen-specific T-bet+ (Th1) OT-II cells transiently during the early stage of infection with transgenic Plasmodium yoelii NL parasites expressing ovalbumin (P. yoelii NL-OVA). We reveal that co-blockade of Tim-3 and PD-L1 during the acute phase of P. yoelii NL infection did not improve the Th1 cell response but instead led to a specific reduction in the numbers of splenic Th1 OT-II cells. Combined blockade of Tim-3 and PD-L1 did elevate anti-parasite IgG antibody responses. Nevertheless, coblockade of Tim-3 and PD-L1 did not affect IFN- production by OT-II cells and did not influence parasite control during P. yoelii NL-OVA infection.Conclusion: Thus, our results show that Tim-3 plays an unexpected combinatorial role with PD-1 in promoting and / or sustaining a Th1 cell response during the early phase of blood-stage P. yoelii NL infection but combined blockade does not dramatically influence anti-parasite immunity.

BackgroundThe gut microbiota is known to influence virtually all facets of human health. Recent work has highlighted a potential role for the gut microbiota in neurological health through the microbiome-gut-brain axis. Microbes can influence the brain both directly and indirectly; through neurotransmitter production, induction of host immunomodulators, or through the release or induction of other microbial or host molecules.MethodsHere we used mass spectrometry imaging (MSI), a label-free imaging tool, to map the molecular changes that occur in the murine gut and brain in germ-free, antibiotic-treated and control mice.ResultsWe determined the spatial distribution and relative quantification of neurotransmitters and their precursors across brain and gut sections in response to the microbiome. Using untargeted MSI of small molecules, we detected a significant change in the levels of four identified metabolites in the brains of germ-free animals compared to controls; vitamin B5, 3-hydroxy-3-methylglutaric acid, 3-methyl-4-(trimethylammonio)butanoate and 4-(trimethylammonio)pentanoate. However, antibiotic treatment induced no significant changes in these metabolites in the brain after one week of treatment.ConclusionsThis work exemplifies the utility of MSI as a tool in determining the spatial distribution and quantification of bacterial and host metabolites in the gut and brain whilst also offering the potential for discovery of novel mediators of microbiome-gut-brain axis communication.

Methyl-CpG-binding domain-2 (Mbd2) acts as an epigenetic regulator of gene expression, by linking DNA methylation to repressive chromatin structure. Although Mbd2 is widely expressed in gastrointestinal immune cells and is implicated in regulating intestinal cancer, anti-helminth responses and response to colonic inflammation, the Mbd2-expressing cell types that control these responses are incompletely defined. Indeed, epigenetic control of gene expression in cells that regulate intestinal immunity is generally poorly understood, even though such mechanisms may explain the inability of standard genetic approaches to pinpoint the causes of conditions like inflammatory bowel disease. In this study we demonstrate a vital role for Mbd2 in regulating murine colonic inflammation. Mbd2-/- mice displayed dramatically worse pathology than wild type controls during dextran sulphate sodium (DSS) induced colitis, with increased inflammatory (IL-1β+) monocytes. Profiling of mRNA from innate immune and epithelial cell (EC) populations suggested that Mbd2 suppresses inflammation and pathology via control of innate-epithelial cell crosstalk and T cell recruitment. Consequently, restriction of Mbd2 deficiency to CD11c+ dendritic cells and macrophages, or to ECs, resulted in increased DSS colitis severity. Our identification of this dual role for Mbd2 in regulating the inflammatory capacity of both CD11c+ cells and ECs highlights how epigenetic control mechanisms may limit intestinal inflammatory responses.

We present a method for tyrosine-selective and reversible bioconjugation; tyrosines are enzymatically converted into catechols and in situ "clicked" onto boronic acids. Importantly, our process selectively produces catechols and avoids quinones, thereby improving the control over the chemical identity of the products. We have conjugated boronic acid-containing hyaluronic acid (HyA) to peptides bearing tyrosines in variable number and position; the use of tagging peptides for the provision of well exposed tyrosine residues-in our case the hemagglutinin-derived HA-tag-makes our approach applicable to virtually any protein; we have demonstrated this concept by conjugating HA-tagged ovalbumin to HyA, thereby also showing the feasibility of producing chimeric proteoglycans. A caveat of this appproach is that, although the formation of boronic esters does not affect the biological recognition of substrates (ovalbumin and HyA), the introduction of catechols may alter some of their biological properties: for example, only after tyrosinase treatment ovalbumin directly induced dendritic cell maturation, either alone or as a HyA conjugate.

Aims: Resident and peripherally derived glioma associated microglia/macrophages (GAMM) play a key role in driving tumour progression, angiogenesis, invasion and attenuating host immune responses. Differentiating these cells’ origins is challenging and current preclinical models such as irradiation-based adoptive transfer, parabiosis and transgenic mice have limitations. We aimed to develop a novel nonmyeloablative transplan- tation (NMT) mouse model that permits high levels of peripheral chimerism without blood-brain barrier (BBB) damage or brain infiltration prior to tumour implantation. Methods: NMT dosing was determined in C57BL/6J or Pep3/CD45.1 mice conditioned with concentrations of busulfan ranging from 25 mg/kg to 125 mg/kg. Donor haematopoietic cells labelled with eGFP or CD45.2 were injected via tail vein. Donor chimerism was measured in peripheral blood, bone marrow and spleen using flow cytometry. BBB integrity was assessed with anti-IgG and anti-fibrinogen antibodies. Immuno-competent chimerised animals were orthotopically implanted with murine glioma GL-261 cells. Central and peripheral cell contributions were assessed using mimmunohistochemistry and flow cytometry. GAMM subpopulation analysis of peripheral cells was performed using Ly6C/MHCII/MerTK/CD64. Results: NMT achieves >80% haematopoietic chimerism by 12 weekswithout BBB damage and normal life span. Bone marrow derived cells (BMDC) and peripheral macrophages accounted for approximately 45% of the GAMM population in GL-261 implanted tumours. Existing markers such as CD45 high/low proved inaccurate to determine central and peripheral populations while Ly6C/MHCII/MerTK/CD64 reliably differentiated GAMM subpopulations in chimerised and unchimerised mice. Conclusion: NMT is a powerful method for dissecting tumour microglia and macrophage subpopulations and can guide further investigation of BMDC subsets in glioma and neuro-inflammatory diseases.

Background:\ud \ud The present study investigated factors associated with pre-neoadjuvant chemotherapy (NAC), and pre-operative anaemia, and examined their impact on outcomes in patients with oesophago-gastric cancer treated with curative intent.\ud \ud Methods:\ud \ud Patients diagnosed with oesophago-gastric cancer (January 2010 to December 2015) and treated with curative intent by NAC then surgery at a tertiary centre were included. Patients were grouped by the presence of anaemia (haemoglobin 100 fL) subgroups. Categorical data were analysed by chi-squared test and overall survival by univariate and multivariate Cox regression.\ud \ud Results:\ud \ud 99/295 (34%) patients who received NAC were diagnosed with pre-NAC anaemia, and 157/268 (59%) of patients who subsequently underwent surgery were diagnosed with pre-operative anaemia. Normocytic anaemia was the most common, with 76 (26%) in pre-NAC and 107 (40%) in pre-operative groups. Pre-NAC anaemia was associated with increasing clinical N stage (p = 0.022), higher modified Glasgow Prognostic Score (mGPS) (p = 0.006), and a higher rate of intra-operative transfusion (p = 0.030). Pre-operative anaemia was associated with pre-NAC anaemia (p = 0.004), increasing age (p = 0.026), higher pre-operative mGPS (p = 0.021), and a higher rate of intra-operative transfusion (p = 0.021). Anaemia before NAC and surgery was associated with poorer overall survival in patient following R0 resection, independent of stage (HR 1.26, 95% CI 1.02–1.54, p = 0.030).\ud \ud Conclusion:\ud \ud Anaemia was associated with poorer overall survival and greater requirement for intra-operative blood transfusion in oesophago-gastric cancer patients undergoing treatment with curative intent.

Type 2 inflammation is a defining feature of infection with parasitic worms(helminths), as well as being responsible for widespread suffering in allergies.However, the precise mechanisms involved in T helper (Th) 2 polarization bydendritic cells (DCs) are currently unclear. We have identified a previouslyunrecognized role for type I IFN (IFN-I) in enabling this process. An IFN-Isignature was evident in DCs responding to the helminth Schistosomamansoni or the allergen house dust mite (HDM). Further, IFN-I signaling wasrequired for optimal DC phenotypic activation in response to helminth antigen(Ag), and efficient migration to, and localization with, T cells in the draininglymph node (dLN). Importantly, DCs generated from Ifnar1-/- mice wereincapable of initiating Th2 responses in vivo. These data demonstrate for thefirst time that the influence of IFN-I is not limited to antiviral or bacterialsettings but also has a central role to play in DC initiation of Th2 responses.

Purpose: To investigate the inflammatory response of the ocular surface with different soft contact lens (CL) replacement frequencies and materials. Methods: Twenty soft CL wearers were required to wear 3 lens types: reusable Acuvue 2 (A2), reusable Acuvue Oasys (AO), and daily disposable Acuvue Oasys (AODD), for 1 week in random sequence in 1 eye with the nonlens-wearing eye acting as a control. Three methods were used to assess the subclinical response: tear cytokine evaluation, in vivo confocal microscopy (IVCM), and impression cytology. Results: Of 13 cytokines investigated, differences were observed only for IL-12p70, which was present in greater concentrations for A2 (interocular difference 8.8 pg/mL, 95% confidence interval 5.5–12.1) and AO (8.9 [5.7–12.1]) compared with AODD (3.7 [0.6–6.8]). For IVCM, corneal presumed dendritic cell density was lower for AODD (interocular difference 1.9 [20.1 to 3.9] cells/mm 2) than for both A2 (9.3 [7.2–11.4]) and AO (10.6 [8.6–12.6]). This trend was the same for the other 5 IVCM measures evaluated. The proportion of CD45 + cells in the bulbar conjunctiva was lower for AODD (0.6 [20.3 to 1.5]%) compared with A2 (4.6 [3.7–5.6]) and AO (4.8 [3.9–5.8]). Similar findings were observed for cells in the upper lid margin. Conclusions: This work has demonstrated for the first time that daily disposable CL wear produces a minimal subclinical inflammatory response compared with no lens wear over 1 week. By contrast, this inflammatory response is upregulated with reusable lenses but appears to be similar between hydrogel and silicone hydrogel materials over this short time frame.

Methyl-CpG-binding domain-2 (Mbd2) acts as an epigenetic regulator of gene expression, by linking DNA methylation to repressive chromatin structure. Although Mbd2 is widely expressed in gastrointestinal immune cells and is implicated in regulating intestinal cancer, anti-helminth responses and colonic inflammation, the Mbd2-expressing cell types that control these responses are incompletely defined. Indeed, epigenetic control of gene expression in cells that regulate intestinal immunity is generally poorly understood, even though such mechanisms may explain the inability of standard genetic approaches to pinpoint the causes of conditions like inflammatory bowel disease. In this study we demonstrate a vital role for Mbd2 in regulating murine colonic inflammation. Mbd2−/− mice displayed dramatically worse pathology than wild type controls during dextran sulfate sodium (DSS) induced colitis, with increased inflammatory (IL-1β+) monocytes. Profiling of mRNA from innate immune and epithelial cell (EC) populations suggested that Mbd2 suppresses inflammation and pathology via control of innate-epithelial cell crosstalk and T cell recruitment. Consequently, restriction of Mbd2 deficiency to CD11c+ dendritic cells and macrophages, or to ECs, resulted in increased DSS colitis severity. Our identification of this dual role for Mbd2 in regulating the inflammatory capacity of both CD11c+ cells and ECs highlights how epigenetic control mechanisms may limit intestinal inflammatory responses.

Background: There is uncertainty over optimal management of locally advanced non-metastatic oesophageal and gastric (OG) adenocarcinomas which are deemed irresectable at time of diagnosis due to local tumour or nodal burden. Current practice in our regional centre is to administer chemotherapy in a “downstaging” strategy in the hope of achieving tumour shrinkage to allow radical treatment. Patients without sufficient response to downstaging are treated palliatively. The aim of this study was to review our single unit outcomes of this treatment strategy. Methods: Data was collected retrospectively from electronic patient records on all cases discussed at regional MDT over a 32-month period (January 2015–August 2017). Results: A total of 44 patients [70.5% male, median age 70 years, 13 (29.5%) oesophageal, 12 (27.3%) junctional and 19 (43.2%) gastric] were included in the study. Thirty-six (81.8%) of patients received the full number of planned cycles of chemotherapy; toxicity and disease progression (both 6.8% of cases) were the most common reasons for early cessation of treatment. Seventeen (38.6%) patients underwent resection and an R0 resection was achieved in 13 (76.5%) of these patients. After median follow up of 16.8 months, the median overall survival (OS) in the resection vs. palliative cohorts was 42.6 vs. 16.4 months (P Conclusions: Our data show that a downstaging approach can be successfully implemented (R0 resection achieved) in up to a third of patients with good survival results. Further prospective data identifying patient and pathological characteristics predicting response to treatment are needed to optimise selection into a downstaging programme.