Publications
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Noble A, Durant L, Dilke SM, et al., 2022, Altered Mucosal Immune-Microbiota Interactions in Familial Adenomatous Polyposis, CLINICAL AND TRANSLATIONAL GASTROENTEROLOGY, Vol: 13
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Noble A, Pring ET, Durant L, et al., 2022, Altered immunity to microbiota, B cell activation and depleted gamma delta/resident memory T cells in colorectal cancer, CANCER IMMUNOLOGY IMMUNOTHERAPY, ISSN: 0340-7004
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Jones E, Stentz R, Telatin A, et al., 2021, The Origin of Plasma-Derived Bacterial Extracellular Vesicles in Healthy Individuals and Patients with Inflammatory Bowel Disease: A Pilot Study, GENES, Vol: 12
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- Citations: 6
Reddi D, Durant L, Bernardo D, et al., 2021, In vitro priming of human T cells by dendritic cells provides a screening tool for candidate vaccines for Burkholderia pseudomallei, Vaccines, Vol: 9, Pages: 1-10, ISSN: 2076-393X
Murine dendritic cells, when pulsed with heat-killed Burkholderia pseudomallei and used to immunise naïve mice, have previously been shown to induce protective immunity in vivo. We have now demonstrated the in vitro priming of naïve human T cells against heat-killed B. pseudomallei, by co-culture with syngeneic B. pseudomallei-pulsed dendritic cells. Additionally, we have enriched the DC fraction such that a study of the differential response induced by pulsed DCs of either myeloid or plasmacytoid lineage in syngeneic human T cells was achievable. Whilst both mDCs and pDCs were activated by pulsing, the mDCs contributed the major response to B. pseudomallei with the expression of the migration marker CCR7 and a significantly greater secretion of the proinflammatory TNFα and IL1β. When these DC factions were combined and used to prime syngeneic T cells, a significant proliferation was observed in the CD4+ fraction. Here, we have achieved human T cell priming in vitro with unadjuvanted B. pseudomallei, the causative organism of melioidosis, for which there is currently no approved vaccine. We propose that the approach we have taken could be used to screen for the human cellular response to candidate vaccines and formulations, in order to enhance the cell-mediated immunity required to protect against this intracellular pathogen and potentially more broadly against other, difficult-to-treat intracellular pathogens. To date, the polysaccharide capsule of B. pseudomallei, fused to a standard carrier protein, e.g., Crm, looks a likely vaccine candidate. Dendritic cells (DCs), providing, as they do, the first line of defence to infection, process and present microbial products to the immune system to direct downstream immune responses. Here, we have sought to use DCs ex vivo to identify immunogenic products from heat-killed B. pseudomallei. Using practical volumes of fresh human donor blood, we show that heat-killed B. pseudomallei activated and stimula
Panoskaltsis N, McCarthy NE, Stagg AJ, et al., 2021, Immune reconstitution and clinical recovery following anti-CD28 antibody (TGN1412)-induced cytokine storm, Cancer Immunology Immunotherapy, Vol: 70, Pages: 1127-1142, ISSN: 0340-7004
Cytokine storm can result from cancer immunotherapy or certain infections, including COVID-19. Though short-term immune-related adverse events are routinely described, longer-term immune consequences and sequential immune monitoring are not as well defined. In 2006, six healthy volunteers received TGN1412, a CD28 superagonist antibody, in a first-in-man clinical trial and suffered from cytokine storm. After the initial cytokine release, antibody effect-specific immune monitoring started on Day + 10 and consisted mainly of evaluation of dendritic cell and T-cell subsets and 15 serum cytokines at 21 time-points over 2 years. All patients developed problems with concentration and memory; three patients were diagnosed with mild-to-moderate depression. Mild neutropenia and autoantibody production was observed intermittently. One patient suffered from peripheral dry gangrene, required amputations, and had persistent Raynaud's phenomenon. Gastrointestinal irritability was noted in three patients and coincided with elevated γδT-cells. One had pruritus associated with elevated IgE levels, also found in three other asymptomatic patients. Dendritic cells, initially undetectable, rose to normal within a month. Naïve CD8+ T-cells were maintained at high levels, whereas naïve CD4+ and memory CD4+ and CD8+ T-cells started high but declined over 2 years. T-regulatory cells cycled circannually and were normal in number. Cytokine dysregulation was especially noted in one patient with systemic symptoms. Over a 2-year follow-up, cognitive deficits were observed in all patients following TGN1412 infusion. Some also had signs or symptoms of psychological, mucosal or immune dysregulation. These observations may discern immunopathology, treatment targets, and long-term monitoring strategies for other patients undergoing immunotherapy or with cytokine storm.
Panoskaltsis N, McCarthy NE, Knight SC, 2021, Myelopoiesis of acute inflammation: lessons from TGN1412-induced cytokine storm, Cancer Immunology Immunotherapy, Vol: 70, Pages: 1155-1160, ISSN: 0340-7004
TGN1412, a superagonist monoclonal antibody targeting CD28, caused cytokine storm in six healthy volunteers in a first-in-man study in 2006. Despite clinical improvement and termination of the cytokine release syndrome within days, anemia persisted in all patients with hemoglobin reaching baseline levels as much as 6 months later. Granulocytic dysplasia continued for 20 days in association with increased expression of CD69 and IL-4, but reduced IL-10; with resolution, this profile reversed to higher IL-10 expression and counter-balanced circannual cycling of IL-4 and IL-10 thereafter over 7 months. Along with immune cell subset and cytokine correlates monitored over 2 years, these observations offer unique insights into the expected changes in myelopoiesis and natural resolution in otherwise healthy young individuals in response to acute inflammation and cytokine storm in the absence of concomitant infection or comorbidity.
McCarthy NE, Stagg AJ, Price CL, et al., 2021, Patients with gastrointestinal irritability after TGN1412-induced cytokine storm displayed selective expansion of gut-homing αβ and γδT cells, Cancer Immunology Immunotherapy, Vol: 70, Pages: 1143-1153, ISSN: 0340-7004
Following infusion of the anti-CD28 superagonist monoclonal antibody TGN1412, three of six previously healthy, young male recipients developed gastrointestinal irritability associated with increased expression of 'gut-homing' integrin β7 on peripheral blood αβT cells. This subset of patients with intestinal symptoms also displayed a striking and persistent expansion of putative Vδ2+ γδT cells in the circulation which declined over a 2-year period following drug infusion, concordant with subsiding gut symptoms. These data demonstrate that TGN1412-induced gastrointestinal symptoms were associated with dysregulation of the 'gut-homing' pool of blood αβ and γδT cells, induced directly by the antibody and/or arising from the subsequent cytokine storm.
Dilke SM, Durant LR, Stentz R, et al., 2021, DIRECT MANIPULATION OF THE INTESTINAL MICROBIOME TO INFLUENCE POSTOPERATIVE OUTCOMES, Publisher: OXFORD UNIV PRESS, ISSN: 0007-1323
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Durant L, Stentz R, Noble A, et al., 2020, Bacteroides thetaiotaomicron-derived outer membrane vesicles promote regulatory dendritic cell responses in health but not in inflammatory bowel disease, Microbiome, Vol: 8, ISSN: 2049-2618
BackgroundBacteroides thetaiotaomicron (Bt) is a prominent member of the human intestinal microbiota that, like all Gram-negative bacteria, naturally generates nanosized outer membrane vesicles (OMVs) which bud off from the cell surface. Importantly, OMVs can cross the intestinal epithelial barrier to mediate microbe-host cell crosstalk involving both epithelial and immune cells to help maintain intestinal homeostasis. Here we have examined the interaction between Bt OMVs and blood or colonic mucosa-derived dendritic cells (DC) from healthy individuals and patients with Crohn’s disease (CD) or ulcerative colitis (UC). ResultsIn healthy individuals, Bt OMVs stimulated significant (p<0.05) IL-10 expression by colonic DC, whereas in peripheral blood-derived DC they also stimulated significant (p<0.001 and p<0.01, respectively) expression of IL-6 and the activation marker CD80. Conversely, in UC Bt OMVs were unable to elicit IL-10 expression by colonic DC. There were also reduced numbers of CD103+ DC in the colon of both UC and CD patients compared to controls, supporting a loss of regulatory DC in both diseases. Furthermore, in CD and UC, Bt OMVs elicited a significantly lower proportion of DC which expressed IL-10 (p<0.01 and p<0.001, respectively) in blood compared to controls. These alterations in DC responses to Bt OMVs were seen in patients with inactive disease, and thus are indicative of intrinsic defects in immune responses to this commensal in inflammatory bowel disease (IBD). ConclusionsOverall, our findings suggest a key role for OMVs generated by the commensal gut bacterium Bt in directing a balanced immune response to constituents of the microbiota locally and systemically during health which is altered in IBD patients.
Noble A, Durant L, Hoyles L, et al., 2020, Deficient Resident Memory T Cell and CD8 T Cell Response to Commensals in Inflammatory Bowel Disease., J Crohns Colitis, Vol: 14, Pages: 525-537
BACKGROUND AND AIMS: The intestinal microbiota is closely associated with resident memory lymphocytes in mucosal tissue. We sought to understand how acquired cellular and humoral immunity to the microbiota differ in health versus inflammatory bowel disease [IBD]. METHODS: Resident memory T cells [Trm] in colonic biopsies and local antibody responses to intraepithelial microbes were analysed. Systemic antigen-specific immune T and B cell memory to a panel of commensal microbes was assessed. RESULTS: Systemically, healthy blood showed CD4 and occasional CD8 memory T cell responses to selected intestinal bacteria, but few memory B cell responses. In IBD, CD8 memory T cell responses decreased although B cell responses and circulating plasmablasts increased. Possibly secondary to loss of systemic CD8 T cell responses in IBD, dramatically reduced numbers of mucosal CD8+ Trm and γδ T cells were observed. IgA responses to intraepithelial bacteria were increased. Colonic Trm expressed CD39 and CD73 ectonucleotidases, characteristic of regulatory T cells. Cytokines/factors required for Trm differentiation were identified, and in vitro-generated Trm expressed regulatory T cell function via CD39. Cognate interaction between T cells and dendritic cells induced T-bet expression in dendritic cells, a key mechanism in regulating cell-mediated mucosal responses. CONCLUSIONS: A previously unrecognised imbalance exists between cellular and humoral immunity to the microbiota in IBD, with loss of mucosal T cell-mediated barrier immunity and uncontrolled antibody responses. Regulatory function of Trm may explain their association with intestinal health. Promoting Trm and their interaction with dendritic cells, rather than immunosuppression, may reinforce tissue immunity, improve barrier function, and prevent B cell dysfunction in microbiota-associated disease and IBD aetiology.
Al-Hassi HO, Lee GH, Murugananthan A, et al., 2017, DIFFERENTIAL IMMUNE RESPONSES BETWEEN PROXIMAL AND DISTAL COLORECTAL CANCER, Annual General Meeting of the British-Society-of-Gastroenterology (BSG), Publisher: BMJ PUBLISHING GROUP, Pages: A128-A128, ISSN: 0017-5749
Rahbour G, Warusavitarne J, Hart AL, et al., 2017, Pilot study of immunological factors in non-inflammatory bowel disease enterocutaneous fistulas, International Journal of Surgery, Vol: 41, Pages: 127-133, ISSN: 1743-9191
Background:Tumour necrosis factor alpha (TNF-α) is a cytokine elevated in inflammatory bowel disease enterocutaneous fistula (IBD ECF). Dendritic cells are antigen presenting cells that orchestrate the immune responses and regulate the production of cytokines by immune cells including T cells. No study to date has assessed the level of TNF-α or the presence of dendritic cells in non-IBD ECF. The aim of this study was to assess the inflammatory activity, with a particular emphasis on TNF-α in non-IBD ECF when compared with control small bowel tissue.Methods:Tissue biopsies were obtained from ECF at operation from non-IBD patients and from terminal ileum in normal colonoscopy control patients. After overnight culture, accumulation of intracellular TNF-α was measured by flow cytometry in cells treated with monensin to assess the on-going cytokine production. Data were acquired using FACS Canto II. Unpaired Student's t-test was used to compare variables between groups and p < 0.05 was regarded as significant.Results:The on-going production of TNF-α from dendritic cells (p = 0.0007), putative monocyte and B cell populations (p = 0.04) and CD3+ T cells (p = 0.04) was significantly higher in non-IBD ECF tissue than that from control tissue.Conclusions:This study reveals results which provide evidence for the potential use of anti-TNF-α agents in the treatment of non-IBD ECF. A pilot study to evaluate this treatment as an alternative option in an already surgically challenging group of patients is planned. Positive findings would be a major medical advance with a new use for anti-TNF-α agents.
Noble A, Durant L, Hoyles L, et al., 2017, Dysregulation of cellular vs humoral immunity to the intestinal microbiota in inflammatory bowel disease, JOURNAL OF CROHNS & COLITIS, Vol: 11, Pages: S123-S124, ISSN: 1873-9946
Noble A, Durant L, Hoyles L, et al., 2017, P093 Dysregulation of cellular vs humoral immunity to the intestinal microbiota in inflammatory bowel disease., J Crohns Colitis, Vol: 11, Pages: S123-S124
Bhat P, Hendy P, Reddi D, et al., 2016, Altered tissue homing and cytokine production in dendritic cells and monocytes in Crohn's disease, Journal of Gastroenterology and Hepatology, Vol: 31, Pages: 121-121, ISSN: 1440-1746
Bhat P, Hendy P, Reddi D, et al., 2016, Vitamin D regulates dendritic cell activity and trafficking in Crohn's disease, Journal of Gastroenterology and Hepatology, Vol: 31, Pages: 121-122, ISSN: 1440-1746
Hendy PA, Reddi D, Barnardo D, et al., 2016, CIRCULATING DENDRITIC CELL SUBSETS IN CROHN'S DISEASE SHOW ALTERATIONS IN TISSUE HOMING AND CYTOKINE PRODUCTION, GUT, Vol: 65, Pages: A1-A2, ISSN: 0017-5749
Hendy PA, Reddi D, Barnardo D, et al., 2016, VITAMIN D ENHANCES THE ABILITY OF ANTI-TNF THERAPY TO SUPPRESS DENDRITIC CELL ACTIVITY IN CROHN'S DISEASE, GUT, Vol: 65, Pages: A148-A149, ISSN: 0017-5749
Condamine T, Dominguez GA, Youn JI, et al., 2016, Lectin-type oxidized LDL receptor 1 defines a population of polymorphonuclear myeloid-derived suppressor cells in cancer patients, Science Immunology, Vol: 1, ISSN: 2470-9468
Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) are important regulators of immune responses in cancer and have been directly implicated in the promotion of tumor progression. However, the heterogeneity of these cells and the lack of distinct markers hamper the progress in understanding the biology and clinical importance of these cells. Using partial enrichment of PMN-MDSC with gradient centrifugation, we determined that low-density PMN-MDSC and high-density neutrophils from the same cancer patients had a distinct gene profile. The most prominent changes were observed in the expression of genes associated with endoplasmic reticulum (ER) stress. Unexpectedly, low-density lipoprotein (LDL) was one of the most increased regulators, and its receptor oxidized LDL receptor 1 (OLR1) was one of the most overexpressed genes in PMN-MDSC. Lectin-type oxidized LDL receptor-1 (LOX-1) encoded by OLR1 was practically undetectable in neutrophils in peripheral blood of healthy donors, whereas 5 to 15% of total neutrophils in cancer patients and 15 to 50% of neutrophils in tumor tissues were LOX-1+. In contrast to their LOX-1− counterparts, LOX-1+ neutrophils had gene signature, potent immunosuppressive activity, up-regulation of ER stress, and other biochemical characteristics of PMN-MDSCs. Moreover, induction of ER stress in neutrophils from healthy donors up-regulated LOX-1 expression and converted these cells to suppressive PMN-MDSCs. Thus, we identified a specific marker of human PMN-MDSC associated with ER stress and lipid metabolism, which provides new insights into the biology and potential therapeutic targeting of these cells.
Hendy PA, Reddi D, Barnardo D, et al., 2016, ANTI-TNF THERAPY ALTERS DENDRITIC CELL TRAFFICKING AND CYTOKINE PRODUCTION IN CROHN'S DISEASE, GUT, Vol: 65, Pages: A5-A5, ISSN: 0017-5749
Hendy PA, Reddi D, Bernardo D, et al., 2016, Aberrant Circulating Dendritic Cell Cytokine Production and Homing Profile in Crohn's Disease is Normalised by Anti-TNF-alpha Therapy, 57th Annual Meeting and Residents Fellow Conference of the Society-for-Surgery-of-the-Alimentary-Tract (SSAT) / 52nd Annual Meeting on Digestive Disease Week (DDW) / Meeting of the American-Gastroenterological-Association (AGA), Publisher: W B SAUNDERS CO-ELSEVIER INC, Pages: S817-S818, ISSN: 0016-5085
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Landy J, Ronde E, English N, et al., 2016, Tight junctions in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer, World Journal of Gastroenterology, Vol: 22, Pages: 3117-3126, ISSN: 1007-9327
Malietzis G, Lee GH, Al-Hassi HO, et al., 2016, Body composition of the host influences dendritic cell phenotype in patients treated for colorectal cancer, Tumor Biology, Vol: 37, Pages: 11359-11364, ISSN: 1423-0380
Dendritic cells (DCs) are antigen-presenting cells that can acquire tumour antigens and initiate cytotoxic T cell reactions. Obesity has been proposed as a cause for tumours escaping immune surveillance, but few studies investigate the impact of other body composition parameters. We examined the relationship of DC phenotype with computer tomography (CT)-defined parameters in patients with colorectal cancer (CRC). DCs were identified within peripheral blood mononuclear cells by flow cytometry as HLA-DR positive and negative for markers of other cell lineages in 21 patients. Analysis of CT scans was used to calculate lumbar skeletal muscle index (LSMI) and mean muscle attenuation (MA). Positive correlation between the LSMI and expression of CD40 in all DCs (r = 0.45; p = 0.04) was demonstrated. The MA was positively correlated with scavenger receptor CD36 [all DCs (r = 0.60; p = 0.01) and myeloid DCs (r = 0.63; p < 0.01)]. However, the MA was negatively correlated with CCR7 expression in all DCs (r = −0.46, p = 0.03.) and with CD83 [all DCs (r = −0.63; p = 0.01) and myeloid DCs (r = −0.75; p < 0.01)]. There were no relationships between the fat indexes and the DC phenotype. These results highlight a direct relationship between muscle depletion and changes in stimulatory, migratory and fatty acid-processing potential of DC in patients with CRC.
Knight SC, 2016, Dendritic cell-T cell circuitry in health and changes in inflammatory bowel disease and its treatment, Digestive Diseases, Vol: 34, Pages: 51-57, ISSN: 1421-9875
Abstract Background:Dendritic, antigen-presenting cells (DCs) determine not only whether lymphocytes produce different types of immune response but also tissue-homing profiles of lymphocytes they stimulate. For example, in health, mucosal DC stimulate T cells focused to home to the mucosa; DC/T-cell circuitry thus targets immune responses to specific tissue locations. Therapies being introduced for inflammatory bowel disease (IBD) include antibodies to gut-homing molecules such as α4β7 (Vedolizumab) used ostensibly to block gut-homing lymphocytes. However, such lymphocytes are dependent on the tissue specificity of DC that stimulated them. Key Messages:In health, blood DCs have the potential to home to multiple tissues including gut (α4β7+) and skin (CLA+). DCs have become gut-specific within the intestinal microenvironment stimulated partially by local retinoid to express α4β7 (mucosal homing marker) and/or CCR9 (ileal homing marker) in the absence of skin-specific indicators. They spread veiled extensions, sample their environment, acquire/process antigens, produce cytokines and initiate innate immunity. Myeloid DC also traffic to draining lymph nodes where compartmentalization of adaptive immune responses is determined by DCs from the site of antigen expo-sure which dictate the homing profiles of lymphocytes they stimulate. In IBD, changes in homing/activation of gut DCs stimulate T-cells, and also, greater gut specificity and activation of blood DC reflect site and activity of disease. Homing potential of DC can be modulated toward mucosa or skin by vitamins A and D, respectively. Infliximab or interleukin-6 can divert homing profiles toward skin, perhaps predisposing to skin involvement in IBD. Probiotic bacteria or their products can also change homing profiles of gut DC toward skin homing and away from gut. Conclusions:In conclusion, development of gut focused inflammation and its treatment relies on changes in DC tissue spec
Vora R, Bernardo D, Durant L, et al., 2016, Age-related alterations in blood and colonic dendritic cell properties, Oncotarget, Vol: 7, Pages: 11913-11922, ISSN: 1949-2553
Background Dendritic cells (DC) determine initiation, type and location of immuneresponses and, in adults, show decreased Toll-like receptors and some increasedcytokine levels on ageing. Few studies in children have characterised DC orexplored DC-related mechanisms producing age-related immune changes.Methods Blood and colonic DC phenotypes were determined in healthy adults andchildren by flow cytometry and correlated with aging. Blood DC were divided intoplasmacytoid (pDC) and myeloid (mDC) while only mDC were identified in colon.Serum cytokine levels were determined by multiplex cytokine assays and correlatedwith DC properties.Results The pDC marker BDCA2 (but not CD123) was absent in pre-pubertalchildren and numbers of pDC decreased with age. Blood and colonic DC were moremature and activated in adults. Decrease in pDC numbers correlated with reducedGM-CSF levels with aging, but increasing IL-4 and IL-8 levels correlated with a moreactivated DC profile in blood. CXCL16 levels decreased with age.Conclusions In children, lack of BDCA2, a receptor mediating antigen capture andinhibiting interferon induction, may be immunologically beneficial during immunedevelopment. Conversely, reduced pDC numbers, probably secondary todecreasing GM-CSF and increasing cytokine-induced maturation of DC are likely todetermine deteriorating immunity with ageing.
Hendy P, Reddi D, Bernardo D, et al., 2016, Anti-TNF-alpha therapy normalises aberrant cytokine production and homing profile of circulating dendritic cells in Crohn's disease, JOURNAL OF CROHNS & COLITIS, Vol: 10, Pages: S105-S105, ISSN: 1873-9946
Comino I, Bernardo D, Bancel E, et al., 2016, Identification and molecular characterization of oat peptides implicated on coeliac immune response, Food & Nutrition Research, Vol: 60, ISSN: 1654-6628
Background: Oats provide important nutritional and pharmacological properties,although their safety in coeliac patients remains controversial. Previous studies haveconfirmed that the reactivity of the anti-33-mer monoclonal antibody with different oatvarieties is proportional to the immune responses in terms of T-cell proliferation.Although the impact of these varieties on the adaptive response has been studied, therole of the dendritic cells is still poorly understood. The aim of this study is tocharacterize different oat fractions and to study their effect on dendritic cells fromcoeliac patients.Methods and results: Protein fractions were isolated from oat grains and analysed bySDS-PAGE. Several proteins were characterized in the prolamin fraction usingimmunological and proteomic tools, and by Nano-LC-MS/MS. These proteins,analogous to α- and γ-gliadin-like, showed reactive sequences to anti-33-mer antibodysuggesting their immunogenic potential. That was further confirmed as some of thenewly identified oat peptides had a differential stimulatory capacity on circulatingdendritic cells from coeliac patients compared with healthy controls.Conclusions : This is the first time, to our knowledge, where newly identified oatpeptides have been shown to elicit a differential stimulatory capacity on circulatingdendritic cells obtained from coeliac patients, potential identifying immunogenicproperties of these oat peptides.
Malietzis G, Johns N, Al-Hassi HO, et al., 2016, Low Muscularity and Myosteatosis Is Related to the Host Systemic Inflammatory Response in Patients Undergoing Surgery for Colorectal Cancer, ANNALS OF SURGERY, Vol: 263, Pages: 320-325, ISSN: 0003-4932
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Thompson I, 2015, Manipulation of antigen presenting cells to enhance host immune responses to bacterial infection
Vaccine development for intracellular pathogens, where a protective and long lasting T cell response is desirable, has proved to be a significant challenge. Dendritic cell (DC) vaccination has been used to both elucidate mechanisms important in providing protection against a range of pathogens and more recently as a vaccine strategy in its own right. Additionally, targeting of vaccine antigens via monoclonal antibodies specific to DCs has developed as a more clinically appropriate alternative. This thesis investigates whether DC manipulation can enhance survival and reduce bacterial load in murine models of anthrax and melioidosis. Prophylactic DC vaccination for B. anthracis required CpG ODN 1826 for the maturation of antigen-stimulated DCs in vitro. Following their adoptive transfer, DCs failed to induce an antigen-specific response. However, when combined with the rPA and alum anthrax vaccine, DC vaccination enhanced antigen-specific T cell responses. This approach increased murine survival and significantly reduced bacterial load. DC vaccination as a therapeutic strategy for B. pseudomallei again required CpG ODN 1826 for DC maturation and activation. Antigen stimulated DCs migrated to lymph nodes within 48 hours of adoptive transfer where they induced an antigen-specific T cell response with a mixed Th1/Th17 profile. DC vaccination failed to affect survival with increased splenic weight and bacterial load in two out of three murine efficacy studies. Targeting of the protective B. pseudomallei antigen LolC, conjugated to a monoclonal antibody specific for DEC205, an endocytic DC receptor, failed to induce either a specific immune response or impact survival or bacterial load. Overall, DC vaccination reduced B. anthracis bacterial load when used prophylactically in combination with rPA and alum. As a therapeutic strategy the results are suggestive of DC vaccination enhancing B. pseudomallei infection. Future studies should examine the potential for antigen
Bernardo D, Mann ER, Montalvillo E, et al., 2015, CCR2 mediates dendritic cell recruitment to the human colon but is not responsible for differences observed in dendritic cell subsets, phenotype and function between the proximal and distal colon, Cellular and Molecular Gastroenterology and Hepatology, Vol: 2, Pages: 22-39.e5, ISSN: 2352-345X
Background & aimsMost knowledge about gastrointestinal (GI)-tract dendritic cells (DC) relies on murine studies where CD103+ DC specialize in generating immune tolerance with the functionality of CD11b+/- subsets being unclear. Information about human GI-DC is scarce, especially regarding regional specifications. Here, we characterized human DC properties throughout the human colon.MethodsPaired proximal (right/ascending) and distal (left/descending) human colonic biopsies from 95 healthy subjects were taken; DC were assessed by flow cytometry and microbiota composition assessed by 16S rRNA gene sequencing.ResultsColonic DC identified were myeloid (mDC, CD11c+CD123-) and further divided based on CD103 and SIRPα (human analog of murine CD11b) expression. CD103-SIRPα+ DC were the major population and with CD103+SIRPα+ DC were CD1c+ILT3+CCR2+ (although CCR2 was not expressed on all CD103+SIRPα+ DC). CD103+SIRPα- DC constituted a minor subset that were CD141+ILT3-CCR2-. Proximal colon samples had higher total DC counts and fewer CD103+SIRPα+ cells. Proximal colon DC were more mature than distal DC with higher stimulatory capacity for CD4+CD45RA+ T-cells. However, DC and DC-invoked T-cell expression of mucosal homing markers (β7, CCR9) was lower for proximal DC. CCR2 was expressed on circulating CD1c+, but not CD141+ mDC, and mediated DC recruitment by colonic culture supernatants in transwell assays. Proximal colon DC produced higher levels of cytokines. Mucosal microbiota profiling showed a lower microbiota load in the proximal colon, but with no differences in microbiota composition between compartments.ConclusionsProximal colonic DC subsets differ from those in distal colon being more mature. Targeted immunotherapy using DC in T-cell mediated GI-tract inflammation may therefore need to reflect this immune compartmentalization.
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