Publications by authors named "Jennifer L Marshall"

28 Publications

  • Page 1 of 1

Notch signalling drives synovial fibroblast identity and arthritis pathology.

Nature 2020 06 22;582(7811):259-264. Epub 2020 Apr 22.

Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.

The synovium is a mesenchymal tissue composed mainly of fibroblasts, with a lining and sublining that surround the joints. In rheumatoid arthritis the synovial tissue undergoes marked hyperplasia, becomes inflamed and invasive, and destroys the joint. It has recently been shown that a subset of fibroblasts in the sublining undergoes a major expansion in rheumatoid arthritis that is linked to disease activity; however, the molecular mechanism by which these fibroblasts differentiate and expand is unknown. Here we identify a critical role for NOTCH3 signalling in the differentiation of perivascular and sublining fibroblasts that express CD90 (encoded by THY1). Using single-cell RNA sequencing and synovial tissue organoids, we found that NOTCH3 signalling drives both transcriptional and spatial gradients-emanating from vascular endothelial cells outwards-in fibroblasts. In active rheumatoid arthritis, NOTCH3 and Notch target genes are markedly upregulated in synovial fibroblasts. In mice, the genetic deletion of Notch3 or the blockade of NOTCH3 signalling attenuates inflammation and prevents joint damage in inflammatory arthritis. Our results indicate that synovial fibroblasts exhibit a positional identity that is regulated by endothelium-derived Notch signalling, and that this stromal crosstalk pathway underlies inflammation and pathology in inflammatory arthritis.
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http://dx.doi.org/10.1038/s41586-020-2222-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7841716PMC
June 2020

Outer membrane protein size and LPS O-antigen define protective antibody targeting to the Salmonella surface.

Nat Commun 2020 02 12;11(1):851. Epub 2020 Feb 12.

Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK.

Lipopolysaccharide (LPS) O-antigen (O-Ag) is known to limit antibody binding to surface antigens, although the relationship between antibody, O-Ag and other outer-membrane antigens is poorly understood. Here we report, immunization with the trimeric porin OmpD from Salmonella Typhimurium (STmOmpD) protects against infection. Atomistic molecular dynamics simulations indicate this is because OmpD trimers generate footprints within the O-Ag layer sufficiently sized for a single IgG Fab to access. While STmOmpD differs from its orthologue in S. Enteritidis (SEn) by a single amino-acid residue, immunization with STmOmpD confers minimal protection to SEn. This is due to the OmpD-O-Ag interplay restricting IgG binding, with the pairing of OmpD with its native O-Ag being essential for optimal protection after immunization. Thus, both the chemical and physical structure of O-Ag are key for the presentation of specific epitopes within proteinaceous surface-antigens. This enhances combinatorial antigenic diversity in Gram-negative bacteria, while reducing associated fitness costs.
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http://dx.doi.org/10.1038/s41467-020-14655-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7015928PMC
February 2020

Aryl Hydrocarbon Receptor Interacting Protein Maintains Germinal Center B Cells through Suppression of BCL6 Degradation.

Cell Rep 2019 04;27(5):1461-1471.e4

Center of Biochemical Pharmacology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK; Department of Biological Sciences, Westminster University, London W1W 6UW, UK. Electronic address:

B cell lymphoma-6 (BCL6) is highly expressed in germinal center B cells, but how its expression is maintained is still not completely clear. Aryl hydrocarbon receptor interacting protein (AIP) is a co-chaperone of heat shock protein 90. Deletion of Aip in B cells decreased BCL6 expression, reducing germinal center B cells and diminishing adaptive immune responses. AIP was required for optimal AKT signaling in response to B cell receptor stimulation, and AIP protected BCL6 from ubiquitin-mediated proteasomal degradation by the E3-ubiquitin ligase FBXO11 by binding to the deubiquitinase UCHL1, thus helping to maintain the expression of BCL6. AIP was highly expressed in primary diffuse large B cell lymphomas compared to healthy tissue and other tumors. Our findings describe AIP as a positive regulator of BCL6 expression with implications for the pathobiology of diffuse large B cell lymphoma.
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http://dx.doi.org/10.1016/j.celrep.2019.04.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6506688PMC
April 2019

Podoplanin regulates the migration of mesenchymal stromal cells and their interaction with platelets.

J Cell Sci 2019 02 25;132(5). Epub 2019 Feb 25.

Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK

Mesenchymal stromal cells (MSCs) upregulate podoplanin at sites of infection, chronic inflammation and cancer. Here, we investigated the functional consequences of podoplanin expression on the migratory potential of MSCs and their interactions with circulating platelets. Expression of podoplanin significantly enhanced the migration of MSCs compared to MSCs lacking podoplanin. Rac-1 inhibition altered the membrane localisation of podoplanin and in turn significantly reduced MSC migration. Blocking Rac-1 activity had no effect on the migration of MSCs lacking podoplanin, indicating that it was responsible for regulation of migration through podoplanin. When podoplanin-expressing MSCs were seeded on the basal surface of a porous filter, they were able to capture platelets perfused over the uncoated apical surface and induce platelet aggregation. Similar microthrombi were observed when endothelial cells (ECs) were co-cultured on the apical surface. Confocal imaging shows podoplanin-expressing MSCs extending processes into the EC layer, and these processes could interact with circulating platelets. In both models, platelet aggregation induced by podoplanin-expressing MSCs was inhibited by treatment with recombinant soluble C-type lectin-like receptor 2 (CLEC-2; encoded by the gene ). Thus, podoplanin may enhance the migratory capacity of tissue-resident MSCs and enable novel interactions with cells expressing CLEC-2.
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http://dx.doi.org/10.1242/jcs.222067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6432720PMC
February 2019

Targeting early changes in the synovial microenvironment: a new class of immunomodulatory therapy?

Ann Rheum Dis 2019 02 14;78(2):186-191. Epub 2018 Dec 14.

Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK

Objectives: Controlled immune responses rely on integrated crosstalk between cells and their microenvironment. We investigated whether targeting proinflammatory signals from the extracellular matrix that persist during pathological inflammation provides a viable strategy to treat rheumatoid arthritis (RA).

Methods: Monoclonal antibodies recognising the fibrinogen-like globe (FBG) of tenascin-C were generated by phage display. Clones that neutralised FBG activation of toll-like receptor 4 (TLR4), without impacting pathogenic TLR4 activation, were epitope mapped by crystallography. Antibodies stained synovial biopsies of patients at different stages of RA development. Antibody efficacy in preventing RA synovial cell cytokine release, and in modulating collagen-induced arthritis in rats, was assessed.

Results: Tenascin-C is expressed early in the development of RA, even before disease diagnosis, with higher levels in the joints of people with synovitis who eventually developed RA than in people whose synovitis spontaneously resolved. Anti-FBG antibodies inhibited cytokine release by RA synovial cells and prevented disease progression and tissue destruction during collagen-induced arthritis.

Conclusions: Early changes in the synovial microenvironment contribute to RA progression; blocking proinflammatory signals from the matrix can ameliorate experimental arthritis. These data highlight a new drug class that could offer early, disease-specific immune modulation in RA, without engendering global immune suppression.
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http://dx.doi.org/10.1136/annrheumdis-2018-214294DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6352652PMC
February 2019

Intestinal CD103CD11b cDC2 Conventional Dendritic Cells Are Required for Primary CD4 T and B Cell Responses to Soluble Flagellin.

Front Immunol 2018 17;9:2409. Epub 2018 Oct 17.

Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.

Systemic immunization with soluble flagellin (sFliC) from Typhimurium induces mucosal responses, offering potential as an adjuvant platform for vaccines. Moreover, this engagement of mucosal immunity is necessary for optimal systemic immunity, demonstrating an interaction between these two semi-autonomous immune systems. Although TLR5 and CD103CD11b cDC2 contribute to this process, the relationship between these is unclear in the early activation of CD4 T cells and the development of antigen-specific B cell responses. In this work, we use TLR5-deficient mice and mice (which have reduced numbers of cDC2, particularly intestinal CD103CD11b cDCs), to address these points by studying the responses concurrently in the spleen and the mesenteric lymph nodes (MLN). We show that CD103CD11b cDC2 respond rapidly and accumulate in the MLN after immunization with sFliC in a TLR5-dependent manner. Furthermore, we identify that whilst CD103CD11b cDC2 are essential for the induction of primary T and B cell responses in the mucosa, they do not play such a central role for the induction of these responses in the spleen. Additionally, we show the involvement of CD103CD11b cDC2 in the induction of Th2-associated responses. mice showed a reduced primary FliC-specific Th2-associated IgG1 responses, but enhanced Th1-associated IgG2c responses. These data expand our current understanding of the mucosal immune responses promoted by sFliC and highlights the potential of this adjuvant for vaccine usage by taking advantage of the functionality of mucosal CD103CD11b cDC2.
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http://dx.doi.org/10.3389/fimmu.2018.02409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6199373PMC
October 2019

Functionally distinct disease-associated fibroblast subsets in rheumatoid arthritis.

Nat Commun 2018 02 23;9(1):789. Epub 2018 Feb 23.

Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.

Fibroblasts regulate tissue homeostasis, coordinate inflammatory responses, and mediate tissue damage. In rheumatoid arthritis (RA), synovial fibroblasts maintain chronic inflammation which leads to joint destruction. Little is known about fibroblast heterogeneity or if aberrations in fibroblast subsets relate to pathology. Here, we show functional and transcriptional differences between fibroblast subsets from human synovial tissues using bulk transcriptomics of targeted subpopulations and single-cell transcriptomics. We identify seven fibroblast subsets with distinct surface protein phenotypes, and collapse them into three subsets by integrating transcriptomic data. One fibroblast subset, characterized by the expression of proteins podoplanin, THY1 membrane glycoprotein and cadherin-11, but lacking CD34, is threefold expanded in patients with RA relative to patients with osteoarthritis. These fibroblasts localize to the perivascular zone in inflamed synovium, secrete proinflammatory cytokines, are proliferative, and have an in vitro phenotype characteristic of invasive cells. Our strategy may be used as a template to identify pathogenic stromal cellular subsets in other complex diseases.
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http://dx.doi.org/10.1038/s41467-018-02892-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5824882PMC
February 2018

Stromal cell markers are differentially expressed in the synovial tissue of patients with early arthritis.

PLoS One 2017 9;12(8):e0182751. Epub 2017 Aug 9.

Rheumatology Research Group, Institute of Inflammation and Ageing, The University of Birmingham, United Kingdom.

Introduction: Previous studies have shown increased expression of stromal markers in synovial tissue (ST) of patients with established rheumatoid arthritis (RA). Here, ST expression of stromal markers in early arthritis in relationship to diagnosis and prognostic outcome was studied.

Methods: ST from 56 patients included in two different early arthritis cohorts and 7 non-inflammatory controls was analysed using immunofluorescence to detect stromal markers CD55, CD248, fibroblast activation protein (FAP) and podoplanin. Diagnostic classification (gout, psoriatic arthritis, unclassified arthritis (UA), parvovirus associated arthritis, reactive arthritis and RA), disease outcome (resolving vs persistent) and clinical variables were determined at baseline and after follow-up, and related to the expression of stromal markers.

Results: We observed expression of all stromal markers in ST of early arthritis patients, independent of diagnosis or prognostic outcome. Synovial expression of FAP was significantly higher in patients developing early RA compared to other diagnostic groups and non-inflammatory controls. In RA FAP protein was expressed in both lining and sublining layers. Podoplanin expression was higher in all early inflammatory arthritis patients than controls, but did not differentiate diagnostic outcomes. Stromal marker expression was not associated with prognostic outcomes of disease persistence or resolution. There was no association with clinical or sonographic variables.

Conclusions: Stromal cell markers CD55, CD248, FAP and podoplanin are expressed in ST in the earliest stage of arthritis. Baseline expression of FAP is higher in early synovitis patients who fulfil classification criteria for RA over time. These results suggest that significant fibroblast activation occurs in RA in the early window of disease.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182751PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5549962PMC
October 2017

A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host.

Nature 2017 06 5;546(7659):514-518. Epub 2017 Jun 5.

Winer Observatory, Sonoita, Arizona 85637, USA.

The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside, and is highly inflated-traits that have been linked to high insolation. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.
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http://dx.doi.org/10.1038/nature22392DOI Listing
June 2017

Pathologically expanded peripheral T helper cell subset drives B cells in rheumatoid arthritis.

Nature 2017 02;542(7639):110-114

Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.

CD4 T cells are central mediators of autoimmune pathology; however, defining their key effector functions in specific autoimmune diseases remains challenging. Pathogenic CD4 T cells within affected tissues may be identified by expression of markers of recent activation. Here we use mass cytometry to analyse activated T cells in joint tissue from patients with rheumatoid arthritis, a chronic immune-mediated arthritis that affects up to 1% of the population. This approach revealed a markedly expanded population of PD-1CXCR5CD4 T cells in synovium of patients with rheumatoid arthritis. However, these cells are not exhausted, despite high PD-1 expression. Rather, using multidimensional cytometry, transcriptomics, and functional assays, we define a population of PD-1CXCR5 'peripheral helper' T (T) cells that express factors enabling B-cell help, including IL-21, CXCL13, ICOS, and MAF. Like PD-1CXCR5 T follicular helper cells, T cells induce plasma cell differentiation in vitro through IL-21 secretion and SLAMF5 interaction (refs 3, 4). However, global transcriptomics highlight differences between T cells and T follicular helper cells, including altered expression of BCL6 and BLIMP1 and unique expression of chemokine receptors that direct migration to inflamed sites, such as CCR2, CX3CR1, and CCR5, in T cells. T cells appear to be uniquely poised to promote B-cell responses and antibody production within pathologically inflamed non-lymphoid tissues.
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http://dx.doi.org/10.1038/nature20810DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349321PMC
February 2017

Rheumatoid synovial fibroblasts differentiate into distinct subsets in the presence of cytokines and cartilage.

Arthritis Res Ther 2016 11 18;18(1):270. Epub 2016 Nov 18.

Rheumatology Research Group, Institute of Inflammation and Ageing, University of Birmingham Research Laboratories, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, B15 2WB, UK.

Background: We investigated two distinct synovial fibroblast populations that were located preferentially in the lining or sub-lining layers and defined by their expression of either podoplanin (PDPN) or CD248, and explored their ability to undergo self-assembly and transmigration in vivo.

Methods: Synovial fibroblasts (SF) were cultured in vitro and phenotypic changes following stimulation with interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β1 were examined. To examine the phenotype of SF in vivo, a severe combined immunodeficiency (SCID) human-mouse model of cartilage destruction was utilised.

Results: SF in the lining layer in rheumatoid arthritis (RA) expressed high levels of PDPN compared to the normal synovium, whereas CD248 expression was restricted to sub-lining layer cells. TNF-α or IL1 stimulation in vitro resulted in an increased expression of PDPN. In contrast, stimulation with TGF-β1 induced CD248 expression. In the SCID human-mouse model, rheumatoid SF recapitulated the expression of PDPN and CD248. Fibroblasts adjacent to cartilage expressed PDPN, and attached to, invaded, and degraded cartilage. PDPN CD248 SF preceded the appearance of PDPN CD248 cells in contralateral implants.

Conclusions: We have identified two distinct SF populations identified by expression of either PDPN or CD248 which are located within different anatomical compartments of the inflamed synovial membrane. These markers discriminate between SF subsets with distinct biological properties. As PDPN-expressing cells are associated with early fibroblast migration and cartilage erosion in vivo, we propose that PDPN-expressing cells may be an attractive therapeutic target in RA.
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http://dx.doi.org/10.1186/s13075-016-1156-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5116193PMC
November 2016

Soluble flagellin coimmunization attenuates Th1 priming to Salmonella and clearance by modulating dendritic cell activation and cytokine production.

Eur J Immunol 2015 Aug 24;45(8):2299-311. Epub 2015 Jun 24.

Division of Immunity and Infection, Institute of Biomedical Research, University of Birmingham, Birmingham, UK.

Soluble flagellin (sFliC) from Salmonella Typhimurium (STm) can induce a Th2 response to itself and coadministered antigens through ligation of TLR5. These properties suggest that sFliC could potentially modulate responses to Th1 antigens like live STm if both antigens are given concurrently. After coimmunization of mice with sFliC and STm there was a reduction in Th1 T cells (T-bet(+) IFN-γ(+) CD4 T cells) compared to STm alone and there was impaired clearance of STm. In contrast, there was no significant defect in the early extrafollicular B-cell response to STm. These effects are dependent upon TLR5 and flagellin expression by STm. The mechanism for these effects is not related to IL-4 induced to sFliC but rather to the effects of sFliC coimmunization on DCs. After coimmunization with STm and sFliC, splenic DCs had a lower expression of costimulatory molecules and profoundly altered kinetics of IL-12 and TNFα expression. Ex vivo experiments using in vivo conditioned DCs confirmed the effects of sFliC were due to altered DC function during a critical window in the coordinated interplay between DCs and naïve T cells. This has marked implications for understanding how limits in Th1 priming can be achieved during infection-induced, Th1-mediated inflammation.
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http://dx.doi.org/10.1002/eji.201545564DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4973836PMC
August 2015

Non-cleft causes of velopharyngeal dysfunction: implications for treatment.

Int J Pediatr Otorhinolaryngol 2015 Mar 5;79(3):286-95. Epub 2015 Jan 5.

Division of Speech-Language Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.

Although a history of cleft palate is the most common cause of velopharyngeal dysfunction (VPD), there are other disorders that can also cause hypernasality and/or nasal emission. These include other structural anomalies of the velopharyngeal valve (velopharyngeal insufficiency), neurophysiological disorders that result in inadequate velopharyngeal movement (velopharyngeal incompetence), and even faulty articulation placement in the pharynx (velopharyngeal mislearning). Unfortunately, individuals with non-cleft causes of hypernasality and/or nasal emission do not typically present at a cleft palate/craniofacial center where there are professionals who specialize in the evaluation and treatment of these disorders. As a result, they are often misdiagnosed and do not receive appropriate treatment. In this review, we present various conditions that can cause hypernasality and/or nasal emission during speech. We discuss appropriate treatment based on the underlying cause of the condition. It is important that pediatric otolaryngologists are able to recognize these disorders so that affected patients are referred to specialists in velopharyngeal dysfunction for treatment.
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http://dx.doi.org/10.1016/j.ijporl.2014.12.036DOI Listing
March 2015

Resolving Salmonella infection reveals dynamic and persisting changes in murine bone marrow progenitor cell phenotype and function.

Eur J Immunol 2014 Aug 11;44(8):2318-30. Epub 2014 Jun 11.

MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham, Edgbaston, Birmingham, UK.

The generation of immune cells from BM precursors is a carefully regulated process. This is essential to limit the potential for oncogenesis and autoimmunity yet protect against infection. How infection modulates this is unclear. Salmonella can colonize systemic sites including the BM and spleen. This resolving infection has multiple IFN-γ-mediated acute and chronic effects on BM progenitors, and during the first week of infection IFN-γ is produced by myeloid, NK, NKT, CD4(+) T cells, and some lineage-negative cells. After infection, the phenotype of BM progenitors rapidly but reversibly alters, with a peak ∼ 30-fold increase in Sca-1(hi) progenitors and a corresponding loss of Sca-1(lo/int) subsets. Most strikingly, the capacity of donor Sca-1(hi) cells to reconstitute an irradiated host is reduced; the longer donor mice are exposed to infection, and Sca-1(hi) c-kit(int) cells have an increased potential to generate B1a-like cells. Thus, Salmonella can have a prolonged influence on BM progenitor functionality not directly related to bacterial persistence. These results reflect changes observed in leucopoiesis during aging and suggest that BM functionality can be modulated by life-long, periodic exposure to infection. Better understanding of this process could offer novel therapeutic opportunities to modulate BM functionality and promote healthy aging.
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http://dx.doi.org/10.1002/eji.201344350DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4209805PMC
August 2014

The capsular polysaccharide Vi from Salmonella typhi is a B1b antigen.

J Immunol 2012 Dec 16;189(12):5527-32. Epub 2012 Nov 16.

Medical Research Council Centre for Immune Regulation, School of Immunity and Infection, Institute for Biomedical Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.

Vaccination with purified capsular polysaccharide Vi Ag from Salmonella typhi can protect against typhoid fever, although the mechanism for its efficacy is not clearly established. In this study, we have characterized the B cell response to this vaccine in wild-type and T cell-deficient mice. We show that immunization with typhoid Vi polysaccharide vaccine rapidly induces proliferation in B1b peritoneal cells, but not in B1a cells or marginal zone B cells. This induction of B1b proliferation is concomitant with the detection of splenic Vi-specific Ab-secreting cells and protective Ab in Rag1-deficient B1b cell chimeras generated by adoptive transfer-induced specific Ab after Vi immunization. Furthermore, Ab derived from peritoneal B cells is sufficient to confer protection against Salmonella that express Vi Ag. Expression of Vi by Salmonella during infection did not inhibit the development of early Ab responses to non-Vi Ags. Despite this, the protection conferred by immunization of mice with porin proteins from Salmonella, which induce Ab-mediated protection, was reduced postinfection with Vi-expressing Salmonella, although protection was not totally abrogated. This work therefore suggests that, in mice, B1b cells contribute to the protection induced by Vi Ag, and targeting non-Vi Ags as subunit vaccines may offer an attractive strategy to augment current Vi-based vaccine strategies.
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http://dx.doi.org/10.4049/jimmunol.1103166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3605773PMC
December 2012

Systemic flagellin immunization stimulates mucosal CD103+ dendritic cells and drives Foxp3+ regulatory T cell and IgA responses in the mesenteric lymph node.

J Immunol 2012 Dec 14;189(12):5745-54. Epub 2012 Nov 14.

Medical Research Council Centre for Immune Regulation, Division of Immunity and Infection, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, United Kingdom.

Mucosal immunity is poorly activated after systemic immunization with protein Ags. Nevertheless, induction of mucosal immunity in such a manner would be an attractive and simple way to overcome the intrinsic difficulties in delivering Ag to such sites. Flagellin from Salmonella enterica serovar Typhimurium (FliC) can impact markedly on host immunity, in part via its recognition by TLR5. In this study, we show that systemic immunization with soluble FliC (sFliC) drives distinct immune responses concurrently in the mesenteric lymph nodes (MLN) and the spleen after i.p. and s.c. immunization. In the MLN, but not the spleen, sFliC drives a TLR5-dependent recruitment of CD103(+) dendritic cells (DCs), which correlates with a diminution in CD103(+) DC numbers in the lamina propria. In the MLN, CD103(+) DCs carry Ag and are the major primers of endogenous and transgenic T cell priming. A key consequence of these interactions with CD103(+) DCs in the MLN is an increase in local regulatory T cell differentiation. In parallel, systemic sFliC immunization results in a pronounced switching of FliC-specific B cells to IgA in the MLN but not elsewhere. Loss of TLR5 has more impact on MLN than splenic Ab responses, reflected in an ablation of IgA, but not IgG, serum Ab titers. Therefore, systemic sFliC immunization targets CD103(+) DCs and drives distinct mucosal T and B cell responses. This offers a potential "Trojan horse" approach to modulate mucosal immunity by systemically immunizing with sFliC.
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http://dx.doi.org/10.4049/jimmunol.1202283DOI Listing
December 2012

Thymic function is maintained during Salmonella-induced atrophy and recovery.

J Immunol 2012 Nov 19;189(9):4266-74. Epub 2012 Sep 19.

Medical Research Council Centre for Immune Regulation, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.

Thymic atrophy is a frequent consequence of infection with bacteria, viruses, and parasites and is considered a common virulence trait between pathogens. Multiple reasons have been proposed to explain this atrophy, including premature egress of immature thymocytes, increased apoptosis, or thymic shutdown to prevent tolerance to the pathogen from developing. The severe loss in thymic cell number can reflect an equally dramatic reduction in thymic output, potentially reducing peripheral T cell numbers. In this study, we examine the relationship between systemic Salmonella infection and thymic function. During infection, naive T cell numbers in peripheral lymphoid organs increase. Nevertheless, this occurs despite a pronounced thymic atrophy caused by viable bacteria, with a peak 50-fold reduction in thymocyte numbers. Thymic atrophy is not dependent upon homeostatic feedback from peripheral T cells or on regulation of endogenous glucocorticoids, as demonstrated by infection of genetically altered mice. Once bacterial numbers fall, thymocyte numbers recover, and this is associated with increases in the proportion and proliferation of early thymic progenitors. During atrophy, thymic T cell maturation is maintained, and single-joint TCR rearrangement excision circle analysis reveals there is only a modest fall in recent CD4(+) thymic emigrants in secondary lymphoid tissues. Thus, thymic atrophy does not necessarily result in a matching dysfunctional T cell output, and thymic homeostasis can constantly adjust to systemic infection to ensure that naive T cell output is maintained.
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http://dx.doi.org/10.4049/jimmunol.1200070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3912538PMC
November 2012

CD248 expression on mesenchymal stromal cells is required for post-natal and infection-dependent thymus remodelling and regeneration.

FEBS Open Bio 2012 20;2:187-90. Epub 2012 Jul 20.

Rheumatology Research Group, Institute of Biomedical Research, University of Birmingham, UK ; MRC Centre for Immune Regulation, University of Birmingham, UK.

The role of mesenchymal stromal cells (MSCs) in regulating immune responses in the thymus is currently unclear. Here we report the existence and role of a MSC population in the thymus that expresses the pericyte and MSC marker CD248 (endosialin). We show using a CD248-deficient mouse model, that CD248 expression on these cells is required for full post-natal thymus development and regeneration post-Salmonella infection. In CD248(-/-) mice the thymus is hypocellular and regeneration is poorer, with significant loss of all thymocyte populations. This identifies the requirement of CD248 to maintain optimal thymic cellularity post-partum and infection.
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http://dx.doi.org/10.1016/j.fob.2012.07.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3642154PMC
May 2013

Early B blasts acquire a capacity for Ig class switch recombination that is lost as they become plasmablasts.

Eur J Immunol 2011 Dec 10;41(12):3506-12. Epub 2011 Nov 10.

MRC Centre for Immune Regulation, School of Immunity and Infection, University of Birmingham, Birmingham, UK.

Rapid production of neutralizing antibody can be critical for limiting the spread of infection. Such early antibody results when B-cell blasts mature directly to plasmablasts without forming germinal centers. These extrafollicular responses can involve Ig class switch recombination (CSR), producing antibody that can readily disseminate through infected tissues. The present study identifies the differentiation stage where CSR occurs in an extrafollicular response induced by 4-hydroxy-3-nitrophenyl acetyl (NP) conjugated to Ficoll (NP-Ficoll). To do this, we took advantage of the antigen dose dependency of CSR in this response. Thus, while both 30 and 1 μg NP-Ficoll induce plasmablasts, only the higher antigen dose induces CSR. Activation-induce cytidine deaminase (AID) is critical for CSR and in keeping with this a proportion of NP-specific B-cell blasts induced by 30 μg NP-Ficoll express AID. None of the B blasts responding to the non-CSR-inducing 1 μg dose of NP-Ficoll express AID. We confirmed that CSR occurs in B blasts by demonstrating the presence of rearranged heavy-chain transcripts in B blasts in the 30 μg response. CSR in this extrafollicular response is confined to B blasts, because NP-specific plasmablasts, identified by expressing CD138 and Blimp-1, no longer express AID and cannot undergo CSR.
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http://dx.doi.org/10.1002/eji.201141762DOI Listing
December 2011

CD31 is required on CD4+ T cells to promote T cell survival during Salmonella infection.

J Immunol 2011 Aug 6;187(4):1553-65. Epub 2011 Jul 6.

Medical Research Council Centre for Immune Regulation, School of Immunity and Infection, Institute for Biomedical Research, University of Birmingham, Birmingham B15 2TT, United Kingdom.

Hematopoietic cells constitutively express CD31/PECAM1, a signaling adhesion receptor associated with controlling responses to inflammatory stimuli. Although expressed on CD4(+) T cells, its function on these cells is unclear. To address this, we have used a model of systemic Salmonella infection that induces high levels of T cell activation and depends on CD4(+) T cells for resolution. Infection of CD31-deficient (CD31KO) mice demonstrates that these mice fail to control infection effectively. During infection, CD31KO mice have diminished numbers of total CD4(+) T cells and IFN-γ-secreting Th1 cells. This is despite a higher proportion of CD31KO CD4(+) T cells exhibiting an activated phenotype and an undiminished capacity to prime normally and polarize to Th1. Reduced numbers of T cells reflected the increased propensity of naive and activated CD31KO T cells to undergo apoptosis postinfection compared with wild-type T cells. Using adoptive transfer experiments, we show that loss of CD31 on CD4(+) T cells alone is sufficient to account for the defective CD31KO T cell accumulation. These data are consistent with CD31 helping to control T cell activation, because in its absence, T cells have a greater propensity to become activated, resulting in increased susceptibility to become apoptotic. The impact of CD31 loss on T cell homeostasis becomes most pronounced during severe, inflammatory, and immunological stresses such as those caused by systemic Salmonella infection. This identifies a novel role for CD31 in regulating CD4 T cell homeostasis.
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http://dx.doi.org/10.4049/jimmunol.1000502DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160468PMC
August 2011

B cell priming for extrafollicular antibody responses requires Bcl-6 expression by T cells.

J Exp Med 2011 Jul 27;208(7):1377-88. Epub 2011 Jun 27.

Department of Pathogens and Immunity, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia.

T follicular helper cells (Tfh cells) localize to follicles where they provide growth and selection signals to mutated germinal center (GC) B cells, thus promoting their differentiation into high affinity long-lived plasma cells and memory B cells. T-dependent B cell differentiation also occurs extrafollicularly, giving rise to unmutated plasma cells that are important for early protection against microbial infections. Bcl-6 expression in T cells has been shown to be essential for the formation of Tfh cells and GC B cells, but little is known about its requirement in physiological extrafollicular antibody responses. We use several mouse models in which extrafollicular plasma cells can be unequivocally distinguished from those of GC origin, combined with antigen-specific T and B cells, to show that the absence of T cell-expressed Bcl-6 significantly reduces T-dependent extrafollicular antibody responses. Bcl-6(+) T cells appear at the T-B border soon after T cell priming and before GC formation, and these cells express low amounts of PD-1. Their appearance precedes that of Bcl-6(+) PD-1(hi) T cells, which are found within the GC. IL-21 acts early to promote both follicular and extrafollicular antibody responses. In conclusion, Bcl-6(+) T cells are necessary at B cell priming to form extrafollicular antibody responses, and these pre-GC Tfh cells can be distinguished phenotypically from GC Tfh cells.
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http://dx.doi.org/10.1084/jem.20102065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135363PMC
July 2011

T-zone localized monocyte-derived dendritic cells promote Th1 priming to Salmonella.

Eur J Immunol 2011 Sep 4;41(9):2654-65. Epub 2011 Aug 4.

Medical Research Council Centre for Immune Regulation, School of Immunity and Infection, Institute of Biomedical Research, University of Birmingham, Birmingham, UK.

Control of intracellular Salmonella infection requires Th1 priming and IFN-γ production. Here, we show that efficient Th1 priming after Salmonella infection requires CD11c(+) CD11b(hi) F4/80(+) monocyte-derived dendritic cells (moDCs). In non-infected spleens, moDCs are absent from T-cell zones (T zones) of secondary lymphoid tissues, but by 24 h post-infection moDCs are readily discernible in these sites. The accumulation of moDCs is more dependent upon bacterial viability than bacterial virulence. Kinetic studies showed that moDCs were necessary to prime but not sustain Th1 responses, while ex vivo studies showed that antigen-experienced moDCs were sufficient to induce T-cell proliferation and IFN-γ production via a TNF-α-dependent mechanism. Importantly, moDCs and cDCs when co-cultured induced superior Th1 differentiation than either subset alone, and this activity was independent of TNF-α. Thus, optimal Th1 development to Salmonella requires the rapid accumulation of moDCs within T zones and their collaboration with cDCs.
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http://dx.doi.org/10.1002/eji.201141440DOI Listing
September 2011

Soluble flagellin, FliC, induces an Ag-specific Th2 response, yet promotes T-bet-regulated Th1 clearance of Salmonella typhimurium infection.

Eur J Immunol 2011 Jun 10;41(6):1606-18. Epub 2011 May 10.

MRC Centre for Immune Regulation, University of Birmingham, Birmingham, UK.

Clearance of disseminated Salmonella infection requires bacterial-specific Th1 cells and IFN-γ production, and Th1-promoting vaccines are likely to help control these infections. Consequently, vaccine design has focused on developing Th1-polarizing adjuvants or Ag that naturally induce Th1 responses. In this study, we show that, in mice, immunization with soluble, recombinant FliC protein flagellin (sFliC) induces Th2 responses as evidenced by Ag-specific GATA-3, IL-4 mRNA, and protein induction in CD62L(lo) CD4(+) T cells without associated IFN-γ production. Despite these Th2 features, sFliC immunization can enhance the development of protective Th1 immunity during subsequent Salmonella infection in an Ab-independent, T-cell-dependent manner. Salmonella infection in sFliC-immunized mice resulted in augmented Th1 responses, with greater bacterial clearance and increased numbers of IFN-γ-producing CD4(+) T cells, despite the early induction of Th2 features to sFliC. The augmented Th1 immunity after sFliC immunization was regulated by T-bet although T-bet is dispensable for primary responses to sFliC. These findings show that there can be flexibility in T-cell responses to some subunit vaccines. These vaccines may induce Th2-type immunity during primary immunization yet promote Th1-dependent responses during later infection. This suggests that designing Th1-inducing subunit vaccines may not always be necessary since this can occur naturally during subsequent infection.
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http://dx.doi.org/10.1002/eji.201041089DOI Listing
June 2011

Absent bactericidal activity of mouse serum against invasive African nontyphoidal Salmonella results from impaired complement function but not a lack of antibody.

J Immunol 2011 Feb 7;186(4):2365-71. Epub 2011 Jan 7.

Medical Research Council Centre for Immune Regulation and Clinical Immunology Service, Institute of Biomedical Research, School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.

Nontyphoidal strains of Salmonella are a major cause of fatal bacteremia in Africa. Developing a vaccine requires an improved understanding of the relevant mechanisms of protective immunity, and the mouse model of Salmonella infection is useful for studying immunity to Salmonella in vivo. It is important to appreciate the similarities and differences between immunity to Salmonella in mice and men. Ab is important for protection against nontyphoidal Salmonella in both species, and we have previously found an important role for Ab in cell-free complement-mediated bactericidal activity against Salmonella in Africans. It is unclear whether this modality of immunity is relevant in the mouse model. C57BL/6, BALB/c, and C3H mice immunized with heat-killed Salmonella Typhimurium strains D23580 (African invasive strain) and SL1344 and live-attenuated strain SL3261 produced a Salmonella-specific Ab response. Sera from these mice deposited reduced levels of C3 on Salmonella compared with human sera and were unable to kill both wild-type and galE(-) rough mutant of D23580, indicating absent cell-free killing via classical and alternative complement pathways. Supplementing immune mouse sera with human complement enabled killing of Salmonella, whereas addition of human anti-Salmonella Ab to immune mouse sera had no effect. These findings indicate that mouse serum cannot effect [corrected] cell-free complement-dependent killing of Salmonella, because of the reduced mouse complement ability to kill these bacteria compared with human complement. This difference in Ab-dependent immunity to Salmonella in mice and men must be considered when applying findings from the mouse model of Salmonella disease and vaccination response to man.
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http://dx.doi.org/10.4049/jimmunol.1000284DOI Listing
February 2011

Dysregulated humoral immunity to nontyphoidal Salmonella in HIV-infected African adults.

Science 2010 Apr;328(5977):508-12

Medical Research Council Centre for Immune Regulation and Clinical Immunology Service, Institute of Biomedical Research, School of Immunity and Infection, University of Birmingham, Birmingham, UK.

Nontyphoidal Salmonellae are a major cause of life-threatening bacteremia among HIV-infected individuals. Although cell-mediated immunity controls intracellular infection, antibodies protect against Salmonella bacteremia. We report that high-titer antibodies specific for Salmonella lipopolysaccharide (LPS) are associated with a lack of Salmonella-killing in HIV-infected African adults. Killing was restored by genetically shortening LPS from the target Salmonella or removing LPS-specific antibodies from serum. Complement-mediated killing of Salmonella by healthy serum is shown to be induced specifically by antibodies against outer membrane proteins. This killing is lost when excess antibody against Salmonella LPS is added. Thus, our study indicates that impaired immunity against nontyphoidal Salmonella bacteremia in HIV infection results from excess inhibitory antibodies against Salmonella LPS, whereas serum killing of Salmonella is induced by antibodies against outer membrane proteins.
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http://dx.doi.org/10.1126/science.1180346DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3772309PMC
April 2010

The porin OmpD from nontyphoidal Salmonella is a key target for a protective B1b cell antibody response.

Proc Natl Acad Sci U S A 2009 Jun 1;106(24):9803-8. Epub 2009 Jun 1.

School of Immunity and Infection and Medical Research Council Centre for Immune Regulation, University of Birmingham, Birmingham B15 2TT, United Kingdom.

Invasive nontyphoidal Salmonella (NTS), including Salmonella typhimurium (STm), are major yet poorly-recognized killers of infants in sub-Saharan Africa. Death in these children is usually associated with bacteremia, commonly in the absence of gastrointestinal symptoms. Evidence from humans and animal studies suggest that severe infection and bacteremia occur when specific Ab is lacking. Understanding how Ab responses to Salmonella are regulated will help develop vaccines against these devastating infections. STm induces atypical Ab responses characterized by prominent, accelerated, extrafollicular T-independent (TI) Ab against a range of surface antigens. These responses develop without concomitant germinal centers, which only appear as infection resolves. Here, we show STm rapidly induces a population of TI B220(+)CD5(-) B1b cells during infection and TI Ab from B1b cells targets the outer membrane protein (Omp) porins OmpC, OmpD and OmpF but not flagellin. When porins are used as immunogens they can ablate bacteremia and provide equivalent protection against STm as killed bacterial vaccine and this is wholly B cell-dependent. Furthermore Ab from porin-immunized chimeras, that have B1b cells, is sufficient to impair infection. Infecting with porin-deficient bacteria identifies OmpD, a protein absent from Salmonella Typhi, as a key target of Ab in these infections. This work broadens the recognized repertoire of TI protein antigens and highlights the importance of Ab from different B cell subsets in controlling STm infection. OmpD is a strong candidate vaccine target and may, in part, explain the lack of cross-protection between Salmonella Typhi and STm infections.
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http://dx.doi.org/10.1073/pnas.0812431106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2701014PMC
June 2009

Locus of control and academic achievement in high school students.

Psychol Rep 2006 Apr;98(2):318-22

Morehead State University,

This study investigated the hypothesized relationship between internal locus of control and academic achievement among a sample of 187 students in Grades 8 through 12 using the Nowicki-Strickland Locus of Control Scale for Children. Analysis indicated that students in the higher GPA group reported higher scores on internal locus of control.
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http://dx.doi.org/10.2466/pr0.98.2.318-322DOI Listing
April 2006

BCL6b mediates the enhanced magnitude of the secondary response of memory CD8+ T lymphocytes.

Proc Natl Acad Sci U S A 2005 May 15;102(21):7418-25. Epub 2005 Apr 15.

Wellcome Trust Immunology Unit, Department of Medicine, University of Cambridge, Medical Research Council Centre, Cambridge CB2 2QH, UK.

A characteristic of the secondary response of CD8(+) T cells that distinguishes it from the primary response is the generation of greater numbers of effector cells. Because effector CD8(+) T cells are derived from a pool of less differentiated, replicating cells in secondary lymphoid organs, and because IL-2 mediates effector differentiation, the enhanced secondary response may reflect the enlargement of this generative pool by the transient repression of IL-2-mediated differentiation. We have examined for this function the transcriptional repressor BCL6b, a homologue of BCL6 that represses IL-2-induced B cell differentiation. BCL6b is expressed in a small subset of antigen-experienced CD8(+) T cells. Ectopic expression of BCL6b in CD8(+) T cells diminishes their growth in response to IL-2 in vitro. Female mice in which the BCL6b gene has been interrupted have normal primary responses of CD8(+) T cells to infection with vaccinia expressing the H-Y epitope, Uty, but Uty-specific, BCL6b(-/-), memory CD8(+) T cells have diminished recall proliferative responses to this epitope in vitro. BCL6b(-/-) mice also have normal primary CD8(+) T cell responses to influenza infection, but nucleoprotein peptide-specific, BCL6b(-/-), memory CD8(+) T cells have a cell autonomous defect in the number of effector cells generated in response to reinfection. Therefore, BCL6b is required for the enhanced magnitude of the secondary response of memory CD8(+) T cells.
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http://dx.doi.org/10.1073/pnas.0501585102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140431PMC
May 2005