Invasion of Dendritic Cells, Macrophages and Neutrophils by the Bordetella Adenylate Cyclase Toxin: A Subversive Move to Fool Host Immunity

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Giorgio Fedele

2017-09-01

Full Text Available Adenylate cyclase toxin (CyaA is released in the course of B. pertussis infection in the host’s respiratory tract in order to suppress its early innate and subsequent adaptive immune defense. CD11b-expressing dendritic cells (DC, macrophages and neutrophils are professional phagocytes and key players of the innate immune system that provide a first line of defense against invading pathogens. Recent findings revealed the capacity of B. pertussis CyaA to intoxicate DC with high concentrations of 3′,5′-cyclic adenosine monophosphate (cAMP, which ultimately skews the host immune response towards the expansion of Th17 cells and regulatory T cells. CyaA-induced cAMP signaling swiftly incapacitates opsonophagocytosis, oxidative burst and NO-mediated killing of bacteria by neutrophils and macrophages. The subversion of host immune responses by CyaA after delivery into DC, macrophages and neutrophils is the subject of this review.

Mast cell activators as novel immune regulators.

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Johnson-Weaver, Brandi; Choi, Hae Woong; Abraham, Soman N; Staats, Herman F

2018-05-26

Mast cells are an important cell type of the innate immune system that when activated, play a crucial role in generating protective innate host responses after bacterial and viral infection. Additionally, activated mast cells influence lymph node composition to regulate the induction of adaptive immune responses. The recognition that mast cells play a beneficial role in host responses to microbial infection and induction of adaptive immunity has provided the rationale to evaluate mast cell activators for use as antimicrobials or vaccine adjuvants. This review summarizes the role of mast cell activators in antimicrobial responses while also discussing the use of different classes of mast cell activators as potent vaccine adjuvants that enhance the induction of protective immune responses. Copyright © 2018 Elsevier Ltd. All rights reserved.

Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells

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Pachathundikandi, Suneesh Kumar; Tegtmeyer, Nicole; Backert, Steffen

2013-01-01

Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin α5β1 receptor. Other targeted membrane-based receptors include the integrins αvβ3, αvβ5, and β2 (CD18), RPTP-α/β, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed. PMID:24280762

Evasion of host immune defenses by human papillomavirus.

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Westrich, Joseph A; Warren, Cody J; Pyeon, Dohun

2017-03-02

A majority of human papillomavirus (HPV) infections are asymptomatic and self-resolving in the absence of medical interventions. Various innate and adaptive immune responses, as well as physical barriers, have been implicated in controlling early HPV infections. However, if HPV overcomes these host immune defenses and establishes persistence in basal keratinocytes, it becomes very difficult for the host to eliminate the infection. The HPV oncoproteins E5, E6, and E7 are important in regulating host immune responses. These oncoproteins dysregulate gene expression, protein-protein interactions, posttranslational modifications, and cellular trafficking of critical host immune modulators. In addition to the HPV oncoproteins, sequence variation and dinucleotide depletion in papillomavirus genomes has been suggested as an alternative strategy for evasion of host immune defenses. Since anti-HPV host immune responses are also considered to be important for antitumor immunity, immune dysregulation by HPV during virus persistence may contribute to immune suppression essential for HPV-associated cancer progression. Here, we discuss cellular pathways dysregulated by HPV that allow the virus to evade various host immune defenses. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Trichomonas vaginalis α-Actinin 2 Modulates Host Immune Responses by Inducing Tolerogenic Dendritic Cells via IL-10 Production from Regulatory T Cells.

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Lee, Hye-Yeon; Kim, Juri; Ryu, Jae-Sook; Park, Soon-Jung

2017-08-01

Trichomonas vaginalis is a pathogen that triggers severe immune responses in hosts. T. vaginalis α-actinin 2, Tvα-actinin 2, has been used to diagnose trichomoniasis. This study was undertaken to examine the role of Tvα-actinin 2 as an antigenic molecule to induce immune responses from humans. Western blot analysis using anti-Tvα-actinin 2 antibodies indicated its presence in the secreted proteins of T. vaginalis. ELISA was employed to measure cytokine production by vaginal epithelial cells, prostate cells, mouse dendritic cells (DCs), or T cells stimulated with T. vaginalis or Tvα-actinin 2 protein. Both T. vaginalis and rTvα-actinin 2 induced cytokine production from epithelial cell lines, including IL-10. Moreover, CD4+CD25- regulatory T cells (Treg cells) incubated with rTvα-actinin 2-treated DCs produced high levels of IL-10. These data indicate that Tvα-actinin 2 modulates immune responses via IL-10 production by Treg cells.

DNA Tumor Virus Regulation of Host DNA Methylation and Its Implications for Immune Evasion and Oncogenesis.

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Kuss-Duerkop, Sharon K; Westrich, Joseph A; Pyeon, Dohun

2018-02-13

Viruses have evolved various mechanisms to evade host immunity and ensure efficient viral replication and persistence. Several DNA tumor viruses modulate host DNA methyltransferases for epigenetic dysregulation of immune-related gene expression in host cells. The host immune responses suppressed by virus-induced aberrant DNA methylation are also frequently involved in antitumor immune responses. Here, we describe viral mechanisms and virus-host interactions by which DNA tumor viruses regulate host DNA methylation to evade antiviral immunity, which may contribute to the generation of an immunosuppressive microenvironment during cancer development. Recent trials of immunotherapies have shown promising results to treat multiple cancers; however, a significant number of non-responders necessitate identifying additional targets for cancer immunotherapies. Thus, understanding immune evasion mechanisms of cancer-causing viruses may provide great insights for reversing immune suppression to prevent and treat associated cancers.

DNA Tumor Virus Regulation of Host DNA Methylation and Its Implications for Immune Evasion and Oncogenesis

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Sharon K. Kuss-Duerkop

2018-02-01

Full Text Available Viruses have evolved various mechanisms to evade host immunity and ensure efficient viral replication and persistence. Several DNA tumor viruses modulate host DNA methyltransferases for epigenetic dysregulation of immune-related gene expression in host cells. The host immune responses suppressed by virus-induced aberrant DNA methylation are also frequently involved in antitumor immune responses. Here, we describe viral mechanisms and virus–host interactions by which DNA tumor viruses regulate host DNA methylation to evade antiviral immunity, which may contribute to the generation of an immunosuppressive microenvironment during cancer development. Recent trials of immunotherapies have shown promising results to treat multiple cancers; however, a significant number of non-responders necessitate identifying additional targets for cancer immunotherapies. Thus, understanding immune evasion mechanisms of cancer-causing viruses may provide great insights for reversing immune suppression to prevent and treat associated cancers.

CD19 CAR T Cells Expressing IL-12 Eradicate Lymphoma in Fully Lymphoreplete Mice through Induction of Host Immunity

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Gray Kueberuwa

2018-03-01

Full Text Available Chimeric antigen receptor (CAR T cell therapy represents a significant advancement in cancer therapy. Larger studies have shown ∼90% complete remission rates against chemoresistant and/or refractory CD19+ leukemia or lymphoma. Effective CAR T cell therapy is highly dependent on lymphodepleting preconditioning, which is achieved through chemotherapy or radiotherapy that carries with it significant toxicities. These can exclude patients of low performance status. In order to overcome the need for preconditioning, we constructed fully mouse first and second generation anti-murine CD19 CARs with or without interleukin-12 (IL-12 secretion. To test these CARs, we established a mouse model to reflect the human situation without preconditioning. Murine second generation CAR T cells expressing IL-12 were capable of eradicating established B cell lymphoma with a long-term survival rate of ∼25%. We believe this to be the first study in a truly lymphoreplete model. We provide evidence that IL-12-expressing CAR T cells not only directly kill target CD19+ cells, but also recruit host immune cells to an anti-cancer immune response. This finding is critical because lymphodepletion regimens required for the success of current CAR T cell technology eliminate host immune cells whose anti-cancer activity could otherwise be harnessed by strategies such as IL-12-secreting CAR T cells. Keywords: CD19 CAR T cells, IL-12, immunotherapy, chimeric antigen receptor, adoptive cellular therapy, lymphoma, B cell malignancies, TRUCKs, pre-conditioning

Tumor suppressor maspin as a modulator of host immune response to cancer

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Sijana H. Dzinic

2015-10-01

Full Text Available Despite the promising clinical outcome, the primary challenge of the curative cancer immunotherapy is to overcome the dichotomy of the immune response: tumor-evoked immunostimulatory versus tumor-induced immunosuppressive. The goal needs to be two-fold, to re-establish sustainable antitumor-cancer immunity and to eliminate immunosuppression. The successful elimination of cancer cells by immunosurveillance requires the antigenic presentation of the tumor cells or tumor-associated antigens and the expression of immunostimulatory cytokines and chemokines by cancer and immune cells. Tumors are heterogeneous and as such, some of the tumor cells are thought to have stem cell characteristics that enable them to suppress or desensitize the host immunity due to acquired epigenetic changes. A central mechanism underlying tumor epigenetic instability is the increased histone deacetylase (HDAC-mediated repression of HDAC-target genes regulating homeostasis and differentiation. It was noted that pharmacological HDAC inhibitors are not effective in eliminating tumor cells partly because they may induce immunosuppression. We have shown that epithelial-specific tumor suppressor maspin, an ovalbumin-like non-inhibitory serine protease inhibitor, reprograms tumor cells toward better differentiated phenotypes by inhibiting HDAC1. Recently, we uncovered a novel function of maspin in directing host immunity towards tumor elimination. In this review, we discuss the maspin and maspin/HDAC1 interplay in tumor biology and immunology. We propose that maspin based therapies may eradicate cancer.

Bacteria modulate the CD8+ T cell epitope repertoire of host cytosol-exposed proteins to manipulate the host immune response.

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Yaakov Maman

2011-10-01

Full Text Available The main adaptive immune response to bacteria is mediated by B cells and CD4+ T-cells. However, some bacterial proteins reach the cytosol of host cells and are exposed to the host CD8+ T-cells response. Both gram-negative and gram-positive bacteria can translocate proteins to the cytosol through type III and IV secretion and ESX-1 systems, respectively. The translocated proteins are often essential for the bacterium survival. Once injected, these proteins can be degraded and presented on MHC-I molecules to CD8+ T-cells. The CD8+ T-cells, in turn, can induce cell death and destroy the bacteria's habitat. In viruses, escape mutations arise to avoid this detection. The accumulation of escape mutations in bacteria has never been systematically studied. We show for the first time that such mutations are systematically present in most bacteria tested. We combine multiple bioinformatic algorithms to compute CD8+ T-cell epitope libraries of bacteria with secretion systems that translocate proteins to the host cytosol. In all bacteria tested, proteins not translocated to the cytosol show no escape mutations in their CD8+ T-cell epitopes. However, proteins translocated to the cytosol show clear escape mutations and have low epitope densities for most tested HLA alleles. The low epitope densities suggest that bacteria, like viruses, are evolutionarily selected to ensure their survival in the presence of CD8+ T-cells. In contrast with most other translocated proteins examined, Pseudomonas aeruginosa's ExoU, which ultimately induces host cell death, was found to have high epitope density. This finding suggests a novel mechanism for the manipulation of CD8+ T-cells by pathogens. The ExoU effector may have evolved to maintain high epitope density enabling it to efficiently induce CD8+ T-cell mediated cell death. These results were tested using multiple epitope prediction algorithms, and were found to be consistent for most proteins tested.

The role of rare innate immune cells in Type 2 immune activation against parasitic helminths.

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Webb, Lauren M; Tait Wojno, Elia D

2017-09-01

The complexity of helminth macroparasites is reflected in the intricate network of host cell types that participate in the Type 2 immune response needed to battle these organisms. In this context, adaptive T helper 2 cells and the Type 2 cytokines interleukin (IL)-4, IL-5, IL-9 and IL-13 have been the focus of research for years, but recent work has demonstrated that the innate immune system plays an essential role. Some innate immune cells that promote Type 2 immunity are relatively abundant, such as macrophages and eosinophils. However, we now appreciate that more rare cell types including group 2 innate lymphoid cells, basophils, mast cells and dendritic cells make significant contributions to these responses. These cells are found at low frequency but they are specialized to their roles - located at sites such as the skin, lung and gut, where the host combats helminth parasites. These cells respond rapidly and robustly to worm antigens and worm-induced damage to produce essential cytokines, chemokines, eicosanoids and histamine to activate damaged epithelium and to recruit other effectors. Thus, a greater understanding of how these cells operate is essential to understand how the host protects itself during helminth infection.

Homologous recombination deficiency and host anti-tumor immunity in triple-negative breast cancer.

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Telli, M L; Stover, D G; Loi, S; Aparicio, S; Carey, L A; Domchek, S M; Newman, L; Sledge, G W; Winer, E P

2018-05-07

Triple-negative breast cancer (TNBC) is associated with worse outcomes relative to other breast cancer subtypes. Chemotherapy remains the standard-of-care systemic therapy for patients with localized or metastatic disease, with few biomarkers to guide benefit. We will discuss recent advances in our understanding of two key biological processes in TNBC, homologous recombination (HR) DNA repair deficiency and host anti-tumor immunity, and their intersection. Recent advances in our understanding of homologous recombination (HR) deficiency, including FDA approval of PARP inhibitor olaparib for BRCA1 or BRCA2 mutation carriers, and host anti-tumor immunity in TNBC offer potential for new and biomarker-driven approaches to treat TNBC. Assays interrogating HR DNA repair capacity may guide treatment with agents inducing or targeting DNA damage repair. Tumor infiltrating lymphocytes (TILs) are associated with improved prognosis in TNBC and recent efforts to characterize infiltrating immune cell subsets and activate host anti-tumor immunity offer promise, yet challenges remain particularly in tumors lacking pre-existing immune infiltrates. Advances in these fields provide potential biomarkers to stratify patients with TNBC and guide therapy: induction of DNA damage in HR-deficient tumors and activation of existing or recruitment of host anti-tumor immune cells. Importantly, these advances provide an opportunity to guide use of existing therapies and development of novel therapies for TNBC. Efforts to combine therapies that exploit HR deficiency to enhance the activity of immune-directed therapies offer promise. HR deficiency remains an important biomarker target and potentially effective adjunct to enhance immunogenicity of 'immune cold' TNBCs.

Bacterial immunostat: Mycobacterium tuberculosis lipids and their role in the host immune response

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Adriano Queiroz

Full Text Available Abstract: The lipid-rich cell wall of Mycobacterium tuberculosis is a dynamic structure that is involved in the regulation of the transport of nutrients, toxic host-cell effector molecules, and anti-tuberculosis drugs. It is therefore postulated to contribute to the long-term bacterial survival in an infected human host. Accumulating evidence suggests that M. tuberculosis remodels the lipid composition of the cell wall as an adaptive mechanism against host-imposed stress. Some of these lipid species (trehalose dimycolate, diacylated sulphoglycolipid, and mannan-based lipoglycans trigger an immunopathologic response, whereas others (phthiocerol dimycocerosate, mycolic acids, sulpholipid-1, and di-and polyacyltrehalose appear to dampen the immune responses. These lipids appear to be coordinately expressed in the cell wall of M. tuberculosis during different phases of infection, ultimately determining the clinical fate of the infection. This review summarizes the current state of knowledge on the metabolism, transport, and homeostatic or immunostatic regulation of the cell wall lipids, and their orchestrated interaction with host immune responses that results in bacterial clearance, persistence, or tuberculosis.

Immune modulation by dendritic-cell-based cancer vaccines

Indian Academy of Sciences (India)

The interplay between host immunity and tumour cells has opened the possibility of targeting tumour cells bymodulation of the human immune system. Cancer immunotherapy involves the treatment of a tumour by utilizing therecombinant human immune system components to target the pro-tumour microenvironment or by ...

Yersinia type III effectors perturb host innate immune responses

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Pha, Khavong; Navarro, Lorena

2016-01-01

The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of proinflammatory cytokines and reactive oxygen species, phagocytosis, and induced programmed cell death are processes initiated by innate immune cells in order to combat invading pathogens. However, pathogens have evolved various virulence mechanisms to subvert these responses. One strategy utilized by Gram-negative bacterial pathogens is the deployment of a complex machine termed the type III secretion system (T3SS). The T3SS is composed of a syringe-like needle structure and the effector proteins that are injected directly into a target host cell to disrupt a cellular response. The three human pathogenic Yersinia spp. (Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are Gram-negative bacteria that share in common a 70 kb virulence plasmid which encodes the T3SS. Translocation of the Yersinia effector proteins (YopE, YopH, YopT, YopM, YpkA/YopO, and YopP/J) into the target host cell results in disruption of the actin cytoskeleton to inhibit phagocytosis, downregulation of proinflammatory cytokine/chemokine production, and induction of cellular apoptosis of the target cell. Over the past 25 years, studies on the Yersinia effector proteins have unveiled tremendous knowledge of how the effectors enhance Yersinia virulence. Recently, the long awaited crystal structure of YpkA has been solved providing further insights into the activation of the YpkA kinase domain. Multisite autophosphorylation by YpkA to activate its kinase domain was also shown and postulated to serve as a mechanism to bypass regulation by host phosphatases. In addition, novel Yersinia effector protein targets, such as caspase-1, and signaling pathways including activation of the inflammasome were identified. In this review, we summarize the recent discoveries made on Yersinia

Cell-mediated immunity during syphilis. A review

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Pavia, Charles S.; Folds, James D.; Baseman, Joel B.

1978-01-01

Evidence is presented which reinforces the complexity of the host-parasite interaction during the course of syphilis. Infection with Treponema pallidum evokes a complicated antibody response and an assortment of cell-mediated immune reactions in the host. It appears that humoral immunity plays a minor role towards the complete elimination of syphilitic infection while the cellular limb of the immune response may be an important host defence mechanism. Information now available indicates that a state of anergy, or immunosuppression, exists in the early stages of human and experimental rabbit syphilis based upon negative skin reactions to T. pallidum antigen(s), the abnormal histological appearance of lymphoid organs, and impaired in vitro lymphocyte reactivity. It is also evident that in the later stages of the disease cellular immunity becomes activated as delayed type skin reactions can normally be elicited in tertiary syphilitics and lymphocyte behaviour in cell culture appears normal. Several mechanisms have been invoked to explain the delay in an effective immune response against syphilitic infection and the duration of the disease: (1) a capsule-like substance on the outer surface of virulant T. pallidum may act as a barrier against treponemicidal antibody; (2) this material and other biological properties of virulent treponemes could enable spirochaetes to escape being engulfed by macrophages and other phagocytic cells; (3) antigenic competition among different treponemal antigens causing partial tolerance; (4) T. pallidum infection may bring about the elaboration of immunosuppressive substances of host or treponemal origin which inhibit the proper function of lymphocytes, macrophages, and other cell types. PMID:350348

Immunobiotics for the Bovine Host: Their Interaction with Intestinal Epithelial Cells and Their Effect on Antiviral Immunity

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Julio Villena

2018-03-01

Full Text Available The scientific community has reported several cases of microbes that exhibit elevated rates of antibiotic resistance in different regions of the planet. Due to this emergence of antimicrobial resistant microorganisms, the use of antibiotics as promoters of livestock animals’ growth is being banned in most countries around the world. One of the challenges of agricultural immunology therefore is to find alternatives by modulating the immune system of animals in drug-independent safe food production systems. In this regard, in an effort to supplant antibiotics from bovine feeds, several alternatives were proposed including the use of immunomodulatory probiotics (immunobiotics. The purpose of this review is to provide an update of the status of the modulation of intestinal antiviral innate immunity of the bovine host by immunobiotics, and the beneficial impact of immunobiotics on viral infections, focused on intestinal epithelial cells (IECs. The results of our group, which demonstrate the capacity of immunobiotic strains to beneficially modulate Toll-like receptor 3-triggered immune responses in bovine IECs and improve the resistance to viral infections, are highlighted. This review provides comprehensive information on the innate immune response of bovine IECs against virus, which can be further investigated for the development of strategies aimed to improve defenses in the bovine host.

Comparative Proteomics Identifies Host Immune System Proteins Affected by Infection with Mycobacterium bovis.

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Vladimir López

2016-03-01

Full Text Available Mycobacteria of the Mycobacterium tuberculosis complex (MTBC greatly impact human and animal health worldwide. The mycobacterial life cycle is complex, and the mechanisms resulting in pathogen infection and survival in host cells are not fully understood. Eurasian wild boar (Sus scrofa are natural reservoir hosts for MTBC and a model for mycobacterial infection and tuberculosis (TB. In the wild boar TB model, mycobacterial infection affects the expression of innate and adaptive immune response genes in mandibular lymph nodes and oropharyngeal tonsils, and biomarkers have been proposed as correlates with resistance to natural infection. However, the mechanisms used by mycobacteria to manipulate host immune response are not fully characterized. Our hypothesis is that the immune system proteins under-represented in infected animals, when compared to uninfected controls, are used by mycobacteria to guarantee pathogen infection and transmission. To address this hypothesis, a comparative proteomics approach was used to compare host response between uninfected (TB- and M. bovis-infected young (TB+ and adult animals with different infection status [TB lesions localized in the head (TB+ or affecting multiple organs (TB++]. The results identified host immune system proteins that play an important role in host response to mycobacteria. Calcium binding protein A9, Heme peroxidase, Lactotransferrin, Cathelicidin and Peptidoglycan-recognition protein were under-represented in TB+ animals when compared to uninfected TB- controls, but protein levels were higher as infection progressed in TB++ animals when compared to TB- and/or TB+ adult wild boar. MHCI was the only protein over-represented in TB+ adult wild boar when compared to uninfected TB- controls. The results reported here suggest that M. bovis manipulates host immune response by reducing the production of immune system proteins. However, as infection progresses, wild boar immune response recovers to

Comparative Proteomics Identifies Host Immune System Proteins Affected by Infection with Mycobacterium bovis.

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López, Vladimir; Villar, Margarita; Queirós, João; Vicente, Joaquín; Mateos-Hernández, Lourdes; Díez-Delgado, Iratxe; Contreras, Marinela; Alves, Paulo C; Alberdi, Pilar; Gortázar, Christian; de la Fuente, José

2016-03-01

Mycobacteria of the Mycobacterium tuberculosis complex (MTBC) greatly impact human and animal health worldwide. The mycobacterial life cycle is complex, and the mechanisms resulting in pathogen infection and survival in host cells are not fully understood. Eurasian wild boar (Sus scrofa) are natural reservoir hosts for MTBC and a model for mycobacterial infection and tuberculosis (TB). In the wild boar TB model, mycobacterial infection affects the expression of innate and adaptive immune response genes in mandibular lymph nodes and oropharyngeal tonsils, and biomarkers have been proposed as correlates with resistance to natural infection. However, the mechanisms used by mycobacteria to manipulate host immune response are not fully characterized. Our hypothesis is that the immune system proteins under-represented in infected animals, when compared to uninfected controls, are used by mycobacteria to guarantee pathogen infection and transmission. To address this hypothesis, a comparative proteomics approach was used to compare host response between uninfected (TB-) and M. bovis-infected young (TB+) and adult animals with different infection status [TB lesions localized in the head (TB+) or affecting multiple organs (TB++)]. The results identified host immune system proteins that play an important role in host response to mycobacteria. Calcium binding protein A9, Heme peroxidase, Lactotransferrin, Cathelicidin and Peptidoglycan-recognition protein were under-represented in TB+ animals when compared to uninfected TB- controls, but protein levels were higher as infection progressed in TB++ animals when compared to TB- and/or TB+ adult wild boar. MHCI was the only protein over-represented in TB+ adult wild boar when compared to uninfected TB- controls. The results reported here suggest that M. bovis manipulates host immune response by reducing the production of immune system proteins. However, as infection progresses, wild boar immune response recovers to limit pathogen

Molecular basis of Trypanosoma cruzi and Leishmania interaction with their host(s): exploitation of immune and defense mechanisms by the parasite leading to persistence and chronicity, features reminiscent of immune system evasion strategies in cancer diseases.

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Ouaissi, Ali; Ouaissi, Mehdi

2005-01-01

A number of features occurring during host-parasite interactions in Chagas disease caused by the protozoan parasite, Trypanosoma cruzi, and Leishmaniasis, caused by a group of kinetoplastid protozoan parasites are reminiscent of those observed in cancer diseases. In fact,although the cancer is not a single disease, and that T.cruzi and Leishmania are sophisticated eukaryotic parasites presenting a high level of genotypic variability the growth of the parasites in their host and that of cancer cells share at least one common feature, that is their mutual capacity for rapid cell division. Surprisingly, the parasitic diseases and cancers share some immune evasion strategies. Consideration of these immunological alterations must be added to the evaluation of the pathogenic processes. The molecular and functional characterization of virulence factors and the study of their effect on the arms of the immune system have greatly improved understanding of the regulation of immune effectors functions. The purpose of this review is to analyze some of the current data related to the regulatory components or processes originating from the parasite that control or interfere with host cell physiology. Attempts are also made to delineate some similarities between the immune evasion strategies that parasites and tumors employ. The elucidation of the mode of action of parasite virulence factors toward the host cell allow not only provide us with a more comprehensive view of the host-parasite relationships but may also represent a step forward in efforts aimed to identify new target molecules for therapeutic intervention.

Host defense, dendritic cells and the human lung

NARCIS (Netherlands)

J.M.W. van Haarst (Jan Maarten)

1995-01-01

textabstractHost defense mechanisms protect the body against microorganisms and other foreign structures. These mechanisms can be divided in nonspecific, or innate, and specific, or acquired, immunity. In both branches of immunity the several types of leukocytes (white blood cells) play a dominant

The apolipoprotein L family of programmed cell death and immunity genes rapidly evolved in primates at discrete sites of host-pathogen interactions.

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Smith, Eric E; Malik, Harmit S

2009-05-01

Apolipoprotein L1 (APOL1) is a human protein that confers immunity to Trypanosoma brucei infections but can be countered by a trypanosome-encoded antagonist SRA. APOL1 belongs to a family of programmed cell death genes whose proteins can initiate host apoptosis or autophagic death. We report here that all six members of the APOL gene family (APOL1-6) present in humans have rapidly evolved in simian primates. APOL6, furthermore, shows evidence of an adaptive sweep during recent human evolution. In each APOL gene tested, we found rapidly evolving codons in or adjacent to the SRA-interacting protein domain (SID), which is the domain of APOL1 that interacts with SRA. In APOL6, we also found a rapidly changing 13-amino-acid cluster in the membrane-addressing domain (MAD), which putatively functions as a pH sensor and regulator of cell death. We predict that APOL genes are antagonized by pathogens by at least two distinct mechanisms: SID antagonists, which include SRA, that interact with the SID of various APOL proteins, and MAD antagonists that interact with the MAD hinge base of APOL6. These antagonists either block or prematurely cause APOL-mediated programmed cell death of host cells to benefit the infecting pathogen. These putative interactions must occur inside host cells, in contrast to secreted APOL1 that trafficks to the trypanosome lysosome. Hence, the dynamic APOL gene family appears to be an important link between programmed cell death of host cells and immunity to pathogens.

A bacterial E3 ubiquitin ligase targets a host protein kinase to disrupt plant immunity.

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Rosebrock, Tracy R; Zeng, Lirong; Brady, Jennifer J; Abramovitch, Robert B; Xiao, Fangming; Martin, Gregory B

2007-07-19

Many bacterial pathogens of plants and animals use a type III secretion system to deliver diverse virulence-associated 'effector' proteins into the host cell. The mechanisms by which these effectors act are mostly unknown; however, they often promote disease by suppressing host immunity. One type III effector, AvrPtoB, expressed by the plant pathogen Pseudomonas syringae pv. tomato, has a carboxy-terminal domain that is an E3 ubiquitin ligase. Deletion of this domain allows an amino-terminal region of AvrPtoB (AvrPtoB(1-387)) to be detected by certain tomato varieties leading to immunity-associated programmed cell death. Here we show that a host kinase, Fen, physically interacts with AvrPtoB(1-387 )and is responsible for activating the plant immune response. The AvrPtoB E3 ligase specifically ubiquitinates Fen and promotes its degradation in a proteasome-dependent manner. This degradation leads to disease susceptibility in Fen-expressing tomato lines. Various wild species of tomato were found to exhibit immunity in response to AvrPtoB(1-387 )and not to full-length AvrPtoB. Thus, by acquiring an E3 ligase domain, AvrPtoB has thwarted a highly conserved host resistance mechanism.

Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection.

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Zhang, Jie; Liu, Huan; Wei, Bin

Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1.

Hydrogel elasticity and microarchitecture regulate dental-derived mesenchymal stem cell-host immune system cross-talk.

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Ansari, Sahar; Chen, Chider; Hasani-Sadrabadi, Mohammad Mahdi; Yu, Bo; Zadeh, Homayoun H; Wu, Benjamin M; Moshaverinia, Alireza

2017-09-15

The host immune system (T-lymphocytes and their pro-inflammatory cytokines) has been shown to compromise bone regeneration ability of mesenchymal stem cells (MSCs). We have recently shown that hydrogel, used as an encapsulating biomaterial affects the cross-talk among host immune cells and MSCs. However, the role of hydrogel elasticity and porosity in regulation of cross-talk between dental-derived MSCs and immune cells is unclear. In this study, we demonstrate that the modulus of elasticity and porosity of the scaffold influence T-lymphocyte-dental MSC interplay by regulating the penetration of inflammatory T cells and their cytokines. Moreover, we demonstrated that alginate hydrogels with different elasticity and microporous structure can regulate the viability and determine the fate of the encapsulated MSCs through modulation of NF-kB pathway. Our in vivo data show that alginate hydrogels with smaller pores and higher elasticity could prevent pro-inflammatory cytokine-induced MSC apoptosis by down-regulating the Caspase-3- and 8- associated proapoptotic cascades, leading to higher amounts of ectopic bone regeneration. Additionally, dental-derived MSCs encapsulated in hydrogel with higher elasticity exhibited lower expression levels of NF-kB p65 and Cox-2 in vivo. Taken together, our findings demonstrate that the mechanical characteristics and microarchitecture of the microenvironment encapsulating MSCs, in addition to presence of T-lymphocytes and their pro-inflammatory cytokines, affect the fate of encapsulated dental-derived MSCs. In this study, we demonstrate that alginate hydrogel regulates the viability and the fate of the encapsulated dental-derived MSCs through modulation of NF-kB pathway. Alginate hydrogels with smaller pores and higher elasticity prevent pro-inflammatory cytokine-induced MSC apoptosis by down-regulating the Caspase-3- and 8- associated proapoptotic cascade, leading to higher amounts of ectopic bone regeneration. MSCs encapsulated in

Staphylococcal Immune Evasion Proteins: Structure, Function, and Host Adaptation.

Science.gov (United States)

Koymans, Kirsten J; Vrieling, Manouk; Gorham, Ronald D; van Strijp, Jos A G

2017-01-01

Staphylococcus aureus is a successful human and animal pathogen. Its pathogenicity is linked to its ability to secrete a large amount of virulence factors. These secreted proteins interfere with many critical components of the immune system, both innate and adaptive, and hamper proper immune functioning. In recent years, numerous studies have been conducted in order to understand the molecular mechanism underlying the interaction of evasion molecules with the host immune system. Structural studies have fundamentally contributed to our understanding of the mechanisms of action of the individual factors. Furthermore, such studies revealed one of the most striking characteristics of the secreted immune evasion molecules: their conserved structure. Despite high-sequence variability, most immune evasion molecules belong to a small number of structural categories. Another remarkable characteristic is that S. aureus carries most of these virulence factors on mobile genetic elements (MGE) or ex-MGE in its accessory genome. Coevolution of pathogen and host has resulted in immune evasion molecules with a highly host-specific function and prevalence. In this review, we explore how these shared structures and genomic locations relate to function and host specificity. This is discussed in the context of therapeutic options for these immune evasion molecules in infectious as well as in inflammatory diseases.

Atomic evidence that modification of H-bonds established with amino acids critical for host-cell binding induces sterile immunity against malaria

Energy Technology Data Exchange (ETDEWEB)

Patarroyo, Manuel E., E-mail: mepatarr@mail.com [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Universidad Nacional de Colombia, Bogota (Colombia); Cifuentes, Gladys [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Universidad del Rosario, Bogota (Colombia); Pirajan, Camilo; Moreno-Vranich, Armando [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Vanegas, Magnolia [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Universidad Nacional de Colombia, Bogota (Colombia); Universidad del Rosario, Bogota (Colombia)

2010-04-09

Based on the 3D X-ray crystallographic structures of relevant proteins of the malaria parasite involved in invasion to host cells and 3D NMR structures of High Activity Binding Peptides (HABPs) and their respective analogues, it was found that HABPs are rendered into highly immunogenic and sterile immunity inducers in the Aotus experimental model by modifying those amino acids that establish H-bonds with other HABPs or binding to host's cells. This finding adds striking and novel physicochemical principles, at the atomic level, for a logical and rational vaccine development methodology against infectious disease, among them malaria.

Atomic evidence that modification of H-bonds established with amino acids critical for host-cell binding induces sterile immunity against malaria

International Nuclear Information System (INIS)

Patarroyo, Manuel E.; Cifuentes, Gladys; Pirajan, Camilo; Moreno-Vranich, Armando; Vanegas, Magnolia

2010-01-01

Based on the 3D X-ray crystallographic structures of relevant proteins of the malaria parasite involved in invasion to host cells and 3D NMR structures of High Activity Binding Peptides (HABPs) and their respective analogues, it was found that HABPs are rendered into highly immunogenic and sterile immunity inducers in the Aotus experimental model by modifying those amino acids that establish H-bonds with other HABPs or binding to host's cells. This finding adds striking and novel physicochemical principles, at the atomic level, for a logical and rational vaccine development methodology against infectious disease, among them malaria.

Serratia marcescens Suppresses Host Cellular Immunity via the Production of an Adhesion-inhibitory Factor against Immunosurveillance Cells*

Science.gov (United States)

Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2014-01-01

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis. PMID:24398686

Serratia marcescens suppresses host cellular immunity via the production of an adhesion-inhibitory factor against immunosurveillance cells.

Science.gov (United States)

Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2014-02-28

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis.

Enforcing host cell polarity: an apicomplexan parasite strategy towards dissemination.

Science.gov (United States)

Baumgartner, Martin

2011-08-01

The propagation of apicomplexan parasites through transmitting vectors is dependent on effective dissemination of parasites inside the mammalian host. Intracellular Toxoplasma and Theileria parasites face the challenge that their spread inside the host depends in part on the motile capacities of their host cells. In response, these parasites influence the efficiency of dissemination by altering adhesive and/or motile properties of their host cells. Theileria parasites do so by targeting signalling pathways that control host cell actin dynamics. The resulting enforced polar host cell morphology facilitates motility and invasiveness, by establishing focal adhesion and invasion structures at the leading edge of the infected cell. This parasite strategy highlights mechanisms of motility regulation that are also likely relevant for immune or cancer cell motility. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mycobacterium tuberculosis controls microRNA-99b (miR-99b) expression in infected murine dendritic cells to modulate host immunity.

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Singh, Yogesh; Kaul, Vandana; Mehra, Alka; Chatterjee, Samit; Tousif, Sultan; Dwivedi, Ved Prakash; Suar, Mrutyunjay; Van Kaer, Luc; Bishai, William R; Das, Gobardhan

2013-02-15

Mycobacterium tuberculosis resides and replicates within host phagocytes by modulating host microbicidal responses. In addition, it suppresses the production of host protective cytokines to prevent activation of and antigen presentation by M. tuberculosis-infected cells, causing dysregulation of host protective adaptive immune responses. Many cytokines are regulated by microRNAs (miRNAs), a newly discovered class of small noncoding RNAs, which have been implicated in modulating host immune responses in many bacterial and viral diseases. Here, we show that miRNA-99b (miR-99b), an orphan miRNA, plays a key role in the pathogenesis of M. tuberculosis infection. We found that miR-99b expression was highly up-regulated in M. tuberculosis strain H37Rv-infected dendritic cells (DCs) and macrophages. Blockade of miR-99b expression by antagomirs resulted in significantly reduced bacterial growth in DCs. Interestingly, knockdown of miR-99b in DCs significantly up-regulated proinflammatory cytokines such as IL-6, IL-12, and IL-1β. Furthermore, mRNA and membrane-bound protein data indicated that inhibition of miR-99b augments TNF-α and TNFRSF-4 production. Thus, miR-99b targets TNF-α and TNFRSF-4 receptor genes. Treatment of anti-miR-99b-transfected DCs with anti-TNF-α antibody resulted in increased bacterial burden. Thus, our findings unveil a novel host evasion mechanism adopted by M. tuberculosis via miR-99b, which may open up new avenues for designing miRNA-based vaccines and therapies.

Mycobacterium tuberculosis Controls MicroRNA-99b (miR-99b) Expression in Infected Murine Dendritic Cells to Modulate Host Immunity*

Science.gov (United States)

Singh, Yogesh; Kaul, Vandana; Mehra, Alka; Chatterjee, Samit; Tousif, Sultan; Dwivedi, Ved Prakash; Suar, Mrutyunjay; Van Kaer, Luc; Bishai, William R.; Das, Gobardhan

2013-01-01

Mycobacterium tuberculosis resides and replicates within host phagocytes by modulating host microbicidal responses. In addition, it suppresses the production of host protective cytokines to prevent activation of and antigen presentation by M. tuberculosis-infected cells, causing dysregulation of host protective adaptive immune responses. Many cytokines are regulated by microRNAs (miRNAs), a newly discovered class of small noncoding RNAs, which have been implicated in modulating host immune responses in many bacterial and viral diseases. Here, we show that miRNA-99b (miR-99b), an orphan miRNA, plays a key role in the pathogenesis of M. tuberculosis infection. We found that miR-99b expression was highly up-regulated in M. tuberculosis strain H37Rv-infected dendritic cells (DCs) and macrophages. Blockade of miR-99b expression by antagomirs resulted in significantly reduced bacterial growth in DCs. Interestingly, knockdown of miR-99b in DCs significantly up-regulated proinflammatory cytokines such as IL-6, IL-12, and IL-1β. Furthermore, mRNA and membrane-bound protein data indicated that inhibition of miR-99b augments TNF-α and TNFRSF-4 production. Thus, miR-99b targets TNF-α and TNFRSF-4 receptor genes. Treatment of anti-miR-99b-transfected DCs with anti-TNF-α antibody resulted in increased bacterial burden. Thus, our findings unveil a novel host evasion mechanism adopted by M. tuberculosis via miR-99b, which may open up new avenues for designing miRNA-based vaccines and therapies. PMID:23233675

Epigenetic modulation of host: new insights into immune evasion by ...

Indian Academy of Sciences (India)

Viruses have evolved with their hosts, which include all living species. This has been partly responsible for the development of highly advanced immune systems in the hosts. However, viruses too have evolved ways to regulate and evade the host's immune defence. In addition to mutational mechanisms that viruses employ ...

Mycobacterium tuberculosis co-operonic PE32/PPE65 proteins alter host immune responses by hampering Th1 response

Directory of Open Access Journals (Sweden)

Mohd eKhubaib

2016-05-01

Full Text Available PE/PPE genes, present in cluster with ESAT-6 like genes, are suspected to have a role in antigenic variation and virulence of Mycobacterium tuberculosis. Their roles in immune evasion and immune modulation of host are also well documented. We present evidence that PE32/PPE65 present within the RD8 region are co-operonic, co-transcribed and co-translated, and play role in modulating host immune responses. Experiments with macrophage cell lines revealed that this protein complex suppresses pro-inflammatory cytokines such as TNF-α and IL-6 whereas also inducing high expression of anti-inflammatory IL-10. Immunization of mice with these recombinant proteins dampens an effective Th1 response as evident from reduced frequency of IFN-g and IL-2 producing CD4+ and CD8+ T cells. IgG sub-typing from serum of immunized mice revealed high levels of IgG1 when compared with IgG2a and IgG2b. Further IgG1/IgG2a ratio clearly demonstrated that the protein complex manipulates the host immune response favourable to the pathogen. Our results demonstrate that the co-transcribed and co-translated PE32 and PPE65 antigens are involved specifically in modulating anti-mycobacterial host immune response by hampering Th1 response.

Fluorescent dye labeled influenza virus mainly infects innate immune cells and activated lymphocytes and can be used in cell-mediated immune response assay

OpenAIRE

Xie, Dongxu

2009-01-01

Early results have recognized that influenza virus infects the innate and adaptive immune cells. The data presented in this paper demonstrated that influenza virus labeled with fluorescent dye not only retained the ability to infect and replicate in host cells, but also stimulated a similar human immune response as did unlabeled virus. Influenza virus largely infected the innate and activated adaptive immune cells. Influenza B type virus was different from that of A type virus. B type virus w...

EGFRvIII mCAR-modified T-cell therapy cures mice with established intracerebral glioma and generates host immunity against tumor-antigen loss.

Science.gov (United States)

Sampson, John H; Choi, Bryan D; Sanchez-Perez, Luis; Suryadevara, Carter M; Snyder, David J; Flores, Catherine T; Schmittling, Robert J; Nair, Smita K; Reap, Elizabeth A; Norberg, Pamela K; Herndon, James E; Kuan, Chien-Tsun; Morgan, Richard A; Rosenberg, Steven A; Johnson, Laura A

2014-02-15

Chimeric antigen receptor (CAR) transduced T cells represent a promising immune therapy that has been shown to successfully treat cancers in mice and humans. However, CARs targeting antigens expressed in both tumors and normal tissues have led to significant toxicity. Preclinical studies have been limited by the use of xenograft models that do not adequately recapitulate the immune system of a clinically relevant host. A constitutively activated mutant of the naturally occurring epidermal growth factor receptor (EGFRvIII) is antigenically identical in both human and mouse glioma, but is also completely absent from any normal tissues. We developed a third-generation, EGFRvIII-specific murine CAR (mCAR), and performed tests to determine its efficacy in a fully immunocompetent mouse model of malignant glioma. At elevated doses, infusion with EGFRvIII mCAR T cells led to cures in all mice with brain tumors. In addition, antitumor efficacy was found to be dependent on lymphodepletive host conditioning. Selective blockade with EGFRvIII soluble peptide significantly abrogated the activity of EGFRvIII mCAR T cells in vitro and in vivo, and may offer a novel strategy to enhance the safety profile for CAR-based therapy. Finally, mCAR-treated, cured mice were resistant to rechallenge with EGFRvIII(NEG) tumors, suggesting generation of host immunity against additional tumor antigens. All together, these data support that third-generation, EGFRvIII-specific mCARs are effective against gliomas in the brain and highlight the importance of syngeneic, immunocompetent models in the preclinical evaluation of tumor immunotherapies. ©2013 AACR

Innate Immunity Evasion by Enteroviruses: Insights into Virus-Host Interaction

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Xiaobo Lei

2016-01-01

Full Text Available Enterovirus genus includes multiple important human pathogens, such as poliovirus, coxsackievirus, enterovirus (EV A71, EV-D68 and rhinovirus. Infection with EVs can cause numerous clinical conditions including poliomyelitis, meningitis and encephalitis, hand-foot-and-mouth disease, acute flaccid paralysis, diarrhea, myocarditis and respiratory illness. EVs, which are positive-sense single-stranded RNA viruses, trigger activation of the host antiviral innate immune responses through pathogen recognition receptors such as retinoic acid-inducible gene (RIG-I-likeand Toll-like receptors. In turn, EVs have developed sophisticated strategies to evade host antiviral responses. In this review, we discuss the interplay between the host innate immune responses and EV infection, with a primary focus on host immune detection and protection against EV infection and viral strategies to evade these antiviral immune responses.

Age-Dependent Differences in Systemic and Cell-Autonomous Immunity to L. monocytogenes

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Ashley M. Sherrid

2013-01-01

Full Text Available Host defense against infection can broadly be categorized into systemic immunity and cell-autonomous immunity. Systemic immunity is crucial for all multicellular organisms, increasing in importance with increasing cellular complexity of the host. The systemic immune response to Listeria monocytogenes has been studied extensively in murine models; however, the clinical applicability of these findings to the human newborn remains incompletely understood. Furthermore, the ability to control infection at the level of an individual cell, known as “cell-autonomous immunity,” appears most relevant following infection with L. monocytogenes; as the main target, the monocyte is centrally important to innate as well as adaptive systemic immunity to listeriosis. We thus suggest that the overall increased risk to suffer and die from L. monocytogenes infection in the newborn period is a direct consequence of age-dependent differences in cell-autonomous immunity of the monocyte to L. monocytogenes. We here review what is known about age-dependent differences in systemic innate and adaptive as well as cell-autonomous immunity to infection with Listeria monocytogenes.

Recent progress in host immunity to avian coccidiosis: IL-17 family cytokines as sentinels of the intestinal mucosa.

Science.gov (United States)

Min, Wongi; Kim, Woo H; Lillehoj, Erik P; Lillehoj, Hyun S

2013-11-01

The molecular and cellular mechanisms leading to immune protection against coccidiosis are complex and include multiple aspects of innate and adaptive immunities. Innate immunity is mediated by various subpopulations of immune cells that recognize pathogen associated molecular patterns (PAMPs) through their pattern recognition receptors (PRRs) leading to the secretion of soluble factors with diverse functions. Adaptive immunity, which is important in conferring protection against subsequent reinfections, involves subtypes of T and B lymphocytes that mediate antigen-specific immune responses. Recently, global gene expression microarray analysis has been used in an attempt to dissect this complex network of immune cells and molecules during avian coccidiosis. These new studies emphasized the uniqueness of the innate immune response to Eimeria infection, and directly led to the discovery of previously uncharacterized host genes and proteins whose expression levels were modulated following parasite infection. Among these is the IL-17 family of cytokines. This review highlights recent progress in IL-17 research in the context of host immunity to avian coccidiosis. Copyright © 2013. Published by Elsevier Ltd.

Humoral and cell-mediated immune responses in DNA immunized mink challenged with wild-type canine distemper virus.

Science.gov (United States)

Nielsen, Line; Søgaard, Mette; Karlskov-Mortensen, Peter; Jensen, Trine Hammer; Jensen, Tove Dannemann; Aasted, Bent; Blixenkrone-Møller, Merete

2009-07-30

The aim of the study was to investigate the different phases of the immune response after DNA immunization with the hemagglutinin and nucleoprotein genes from canine distemper virus (CDV). Although attenuated live CDV vaccines have effectively reduced the incidence of disease, canine distemper is still a problem worldwide. The broad host range of CDV creates a constant viral reservoir among wildlife animals. Our results demonstrated early humoral and cell-mediated immune responses (IFN-gamma) in DNA vaccinated mink compared to mock-vaccinated mink after challenge with a Danish wild-type CDV. The DNA vaccine-induced immunity protected the natural host against disease development.

Host control of malaria infections: constraints on immune and erythropoeitic response kinetics.

Directory of Open Access Journals (Sweden)

Philip G McQueen

2008-08-01

Full Text Available The two main agents of human malaria, Plasmodium vivax and Plasmodium falciparum, can induce severe anemia and provoke strong, complex immune reactions. Which dynamical behaviors of host immune and erythropoietic responses would foster control of infection, and which would lead to runaway parasitemia and/or severe anemia? To answer these questions, we developed differential equation models of interacting parasite and red blood cell (RBC populations modulated by host immune and erythropoietic responses. The model immune responses incorporate both a rapidly responding innate component and a slower-responding, long-term antibody component, with several parasite developmental stages considered as targets for each type of immune response. We found that simulated infections with the highest parasitemia tended to be those with ineffective innate immunity even if antibodies were present. We also compared infections with dyserythropoiesis (reduced RBC production during infection to those with compensatory erythropoiesis (boosted RBC production or a fixed basal RBC production rate. Dyserythropoiesis tended to reduce parasitemia slightly but at a cost to the host of aggravating anemia. On the other hand, compensatory erythropoiesis tended to reduce the severity of anemia but with enhanced parasitemia if the innate response was ineffective. For both parasite species, sharp transitions between the schizont and the merozoite stages of development (i.e., with standard deviation in intra-RBC development time immune response, though P. vivax attacks a much smaller subset of RBCs. Since most P. vivax infections are nonlethal (if debilitating clinically, this suggests that P

Rim Pathway-Mediated Alterations in the Fungal Cell Wall Influence Immune Recognition and Inflammation.

Science.gov (United States)

Ost, Kyla S; Esher, Shannon K; Leopold Wager, Chrissy M; Walker, Louise; Wagener, Jeanette; Munro, Carol; Wormley, Floyd L; Alspaugh, J Andrew

2017-01-31

Compared to other fungal pathogens, Cryptococcus neoformans is particularly adept at avoiding detection by innate immune cells. To explore fungal cellular features involved in immune avoidance, we characterized cell surface changes of the C. neoformans rim101Δ mutant, a strain that fails to organize and shield immunogenic epitopes from host detection. These cell surface changes are associated with an exaggerated, detrimental inflammatory response in mouse models of infection. We determined that the disorganized strain rim101Δ cell wall increases macrophage detection in a contact-dependent manner. Using biochemical and microscopy methods, we demonstrated that the rim101Δ strain shows a modest increase in the levels of both cell wall chitin and chitosan but that it shows a more dramatic increase in chito-oligomer exposure, as measured by wheat germ agglutinin staining. We also created a series of mutants with various levels of cell wall wheat germ agglutinin staining, and we demonstrated that the staining intensity correlates with the degree of macrophage activation in response to each strain. To explore the host receptors responsible for recognizing the rim101Δ mutant, we determined that both the MyD88 and CARD9 innate immune signaling proteins are involved. Finally, we characterized the immune response to the rim101Δ mutant in vivo, documenting a dramatic and sustained increase in Th1 and Th17 cytokine responses. These results suggest that the Rim101 transcription factor actively regulates the C. neoformans cell wall to prevent the exposure of immune stimulatory molecules within the host. These studies further explored the ways in which immune cells detect C. neoformans and other fungal pathogens by mechanisms that include sensing N-acetylglucosamine-containing structures, such as chitin and chitosan. Infectious microorganisms have developed many ways to avoid recognition by the host immune system. For example, pathogenic fungi alter their cell surfaces to

[NKT cells and graft-versus-host disease-review].

Science.gov (United States)

Zhao, Lei; Hao, Sha; Yuan, Wei-Ping; Cheng, Tao

2013-10-01

NKT cells (nature killer T cells), as a regulatory cellular compartment in the immune system, express cell surface markers of T cells and NK cells. It secretes a variety of cytokines that stimulate specific antigens. Through regulating the balance of Th1/Th2, the NKT cells play an important role in prevention and treatment of graft-versus-host disease (GVHD). Its antitumor and anti-infectious effects serve as a basis of its application in allogeneic hematopoietic stem cell transplantation. A better understanding of the biological and immunological features of NKT cell, as well as its specific immune regulatory mechanisms, will further justify the rationales of using NKT cells in the management of GVHD for patients. In this review, the biologic properties, classification, differentiation and development, immune activation of NKT cells as well as the NKT cells and GVHD including the related mechanisms of prevention and treatment of GVHD with NKT cells, NKT cells and tumors, NKT cells and infection, and NKT cells and clinical GVHD are summarized.

Characterization of host immune responses in Ebola virus infections.

Science.gov (United States)

Wong, Gary; Kobinger, Gary P; Qiu, Xiangguo

2014-06-01

Ebola causes highly lethal hemorrhagic fever in humans with no licensed countermeasures. Its virulence can be attributed to several immunoevasion mechanisms: an early inhibition of innate immunity started by the downregulation of type I interferon, epitope masking and subversion of the adaptive humoural immunity by secreting a truncated form of the viral glycoprotein. Deficiencies in specific and non-specific antiviral responses result in unrestricted viral replication and dissemination in the host, causing death typically within 10 days after the appearance of symptoms. This review summarizes the host immune response to Ebola infection, and highlights the short- and long-term immune responses crucial for protection, which holds implications for the design of future vaccines and therapeutics.

Regulatory T Cells and Host Anti-CML Responses

National Research Council Canada - National Science Library

Wong, Jr, K. K

2008-01-01

CD4+CD25+FoxP-3+ regulatory T-cells (Tregs) suppress immune responses to "self" antigens, but also have been shown to suppress host anti-tumor responses in several human malignancies, including breast, gastrointestinal, and ovarian cancer...

Rapid host immune response and viral dynamics in herpes simplex virus-2 infection

Science.gov (United States)

Schiffer, Joshua T; Corey, Lawrence

2014-01-01

Herpes Simplex Virus-2 (HSV-2) is episodically shed throughout the human genital tract. While high viral load correlates with development of genital ulcers, shedding also commonly occurs even when ulcers are not present, allowing for silent transmission during coitus and contributing to high seroprevalence of HSV-2 worldwide. Frequent viral reactivation occurs despite diverse and complementary host and viral mechanisms within ganglionic tissue that predispose towards latency, suggesting that viral replication may be constantly occurring in a small minority of neurons within the ganglia. Within genital mucosa, the in vivo expansion and clearance rates of HSV-2 are extremely rapid. Resident dendritic cells and memory HSV-specific T cells persist at prior sites of genital tract reactivation, and in conjunction with prompt innate recognition of infected cells, lead to rapid containment of infected cells. Shedding episodes vary greatly in duration and severity within a single person over time: this heterogeneity appears best explained by variation in the densities of host immunity across the genital tract. The fact that immune responses usually control viral replication in genital skin prior to development of lesions provides optimism that enhancing such responses could lead to effective vaccines and immunotherapies. PMID:23467247

Regulatory T cells and immunity to pathogens.

Science.gov (United States)

Rouse, Barry T; Suvas, Susmit

2007-09-01

Immune responses to pathogens are modulated by one or more types of cells that perform a regulatory function. Some cells with this function, such as CD4+ Foxp3+ natural regulatory T cells (nTreg), pre-exist prior to infections whereas others may be induced as a consequence of infection (adaptive Treg). With pathogens that have a complex pathogenesis, multiple types of regulatory cells could influence the outcome. One major property of Treg is to help minimize collateral tissue damage that can occur during immune reactions to a chronic infection. The consequence is less damage to the host but in such situations the pathogen is likely to establish persistence. In some cases, a fine balance is established between Treg responses, effector components of immunity and the pathogen. Treg responses to pathogens may also act to hamper the efficacy of immune control. This review discusses these issues as well as the likely mechanisms by which various pathogens can signal the participation of Treg during infection.

Modulation of Host Immunity by Human Respiratory Syncytial Virus Virulence Factors: A Synergic Inhibition of Both Innate and Adaptive Immunity

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Gisela Canedo-Marroquín

2017-08-01

Full Text Available The Human Respiratory Syncytial Virus (hRSV is a major cause of acute lower respiratory tract infections (ARTIs and high rates of hospitalizations in children and in the elderly worldwide. Symptoms of hRSV infection include bronchiolitis and pneumonia. The lung pathology observed during hRSV infection is due in part to an exacerbated host immune response, characterized by immune cell infiltration to the lungs. HRSV is an enveloped virus, a member of the Pneumoviridae family, with a non-segmented genome and negative polarity-single RNA that contains 10 genes encoding for 11 proteins. These include the Fusion protein (F, the Glycoprotein (G, and the Small Hydrophobic (SH protein, which are located on the virus surface. In addition, the Nucleoprotein (N, Phosphoprotein (P large polymerase protein (L part of the RNA-dependent RNA polymerase complex, the M2-1 protein as a transcription elongation factor, the M2-2 protein as a regulator of viral transcription and (M protein all of which locate inside the virion. Apart from the structural proteins, the hRSV genome encodes for the non-structural 1 and 2 proteins (NS1 and NS2. HRSV has developed different strategies to evade the host immunity by means of the function of some of these proteins that work as virulence factors to improve the infection in the lung tissue. Also, hRSV NS-1 and NS-2 proteins have been shown to inhibit the activation of the type I interferon response. Furthermore, the hRSV nucleoprotein has been shown to inhibit the immunological synapsis between the dendritic cells and T cells during infection, resulting in an inefficient T cell activation. Here, we discuss the hRSV virulence factors and the host immunological features raised during infection with this virus.

Orchestration of pulmonary T cell immunity during Mycobacterium tuberculosis infection: immunity interruptus

Science.gov (United States)

Behar, Samuel M.; Carpenter, Stephen M.; Booty, Matthew G.; Barber, Daniel L.; Jayaraman, Pushpa

2014-01-01

Despite the introduction almost a century ago of Mycobacterium bovis BCG (BCG), an attenuated form of M. bovis that is used as a vaccine against Mycobacterium tuberculosis, tuberculosis remains a global health threat and kills more than 1.5 million people each year. This is mostly because BCG fails to prevent pulmonary disease – the contagious form of tuberculosis. Although there have been significant advances in understanding how the immune system responds to infection, the qualities that define protective immunity against M. tuberculosis remain poorly characterized. The ability to predict who will maintain control over the infection and who will succumb to clinical disease would revolutionize our approach to surveillance, control, and treatment. Here we review the current understanding of pulmonary T cell responses following M. tuberculosis infection. While infection elicits a strong immune response that contains infection, M. tuberculosis evades eradication. Traditionally, its intracellular lifestyle and alteration of macrophage function are viewed as the dominant mechanisms of evasion. Now we appreciate that chronic inflammation leads to T cell dysfunction. While this may arise as the host balances the goals of bacterial sterilization and avoidance of tissue damage, it is becoming clear that T cell dysfunction impairs host resistance. Defining the mechanisms that lead to T cell dysfunction is crucial as memory T cell responses are likely to be subject to the same subject to the same pressures. Thus, success of T cell based vaccines is predicated on memory T cells avoiding exhaustion while at the same time not promoting overt tissue damage. PMID:25311810

Innate Immune Responses of Bat and Human Cells to Filoviruses: Commonalities and Distinctions.

Science.gov (United States)

Kuzmin, Ivan V; Schwarz, Toni M; Ilinykh, Philipp A; Jordan, Ingo; Ksiazek, Thomas G; Sachidanandam, Ravi; Basler, Christopher F; Bukreyev, Alexander

2017-04-15

Marburg (MARV) and Ebola (EBOV) viruses are zoonotic pathogens that cause severe hemorrhagic fever in humans. The natural reservoir of MARV is the Egyptian rousette bat ( Rousettus aegyptiacus ); that of EBOV is unknown but believed to be another bat species. The Egyptian rousette develops subclinical productive infection with MARV but is refractory to EBOV. Interaction of filoviruses with hosts is greatly affected by the viral interferon (IFN)-inhibiting domains (IID). Our study was aimed at characterization of innate immune responses to filoviruses and the role of filovirus IID in bat and human cells. The study demonstrated that EBOV and MARV replicate to similar levels in all tested cell lines, indicating that permissiveness for EBOV at cell and organism levels do not necessarily correlate. Filoviruses, particularly MARV, induced a potent innate immune response in rousette cells, which was generally stronger than that in human cells. Both EBOV VP35 and VP24 IID were found to suppress the innate immune response in rousette cells, but only VP35 IID appeared to promote virus replication. Along with IFN-α and IFN-β, IFN-γ was demonstrated to control filovirus infection in bat cells but not in human cells, suggesting host species specificity of the antiviral effect. The antiviral effects of bat IFNs appeared not to correlate with induction of IFN-stimulated genes 54 and 56, which were detected in human cells ectopically expressing bat IFN-α and IFN-β. As bat IFN-γ induced the type I IFN pathway, its antiviral effect is likely to be partially induced via cross talk. IMPORTANCE Bats serve as reservoirs for multiple emerging viruses, including filoviruses, henipaviruses, lyssaviruses, and zoonotic coronaviruses. Although there is no evidence for symptomatic disease caused by either Marburg or Ebola viruses in bats, spillover of these viruses into human populations causes deadly outbreaks. The reason for the lack of symptomatic disease in bats infected with

Zinc Homeostasis at the Bacteria/Host Interface-From Coordination Chemistry to Nutritional Immunity.

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Wątły, Joanna; Potocki, Sławomir; Rowińska-Żyrek, Magdalena

2016-11-02

Zinc is one of the most important metal nutrients for species from all kingdoms, being a key structural or catalytic component of hundreds of enzymes, crucial for the survival of both pathogenic microorganisms and their hosts. This work is an overview of the homeostasis of zinc in bacteria and humans. It explains the importance of this metal nutrient for pathogens, describes the roles of zinc sensors, regulators, and transporters, and summarizes various uptake systems and different proteins involved in zinc homeostasis-both those used for storage, buffering, and signaling inside the cell and those excreted in order to obtain Zn II from the host. The human zinc-dependent immune system response is explained, with a special focus given to 'zinc nutritional immunity', a process that describes the competition between the bacteria or fungus and the host for this metal, during which both the pathogen and host make huge efforts to control zinc availability. This sophisticated tug of war over Zn II might be considered as a possible target for novel antibacterial therapies. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immune cells are required for cutaneous ulceration in a swine model of chancroid.

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San Mateo, L R; Toffer, K L; Orndorff, P E; Kawula, T H

1999-09-01

Cutaneous lesions of the human sexually transmitted genital ulcer disease chancroid are characterized by the presence of intraepidermal pustules, keratinocyte cytopathology, and epidermal and dermal erosion. These lesions are replete with neutrophils, macrophages, and CD4(+) T cells and contain very low numbers of cells of Haemophilus ducreyi, the bacterial agent of chancroid. We examined lesion formation by H. ducreyi in a pig model by using cyclophosphamide (CPA)-induced immune cell deficiency to distinguish between host and bacterial contributions to chancroid ulcer formation. Histologic presentation of H. ducreyi-induced lesions in CPA-treated pigs differed from ulcers that developed in immune-competent animals in that pustules did not form and surface epithelia remained intact. However, these lesions had significant suprabasal keratinocyte cytotoxicity. These results demonstrate that the host immune response was required for chancroid ulceration, while bacterial products were at least partially responsible for the keratinocyte cytopathology associated with chancroid lesions in the pig. The low numbers of H. ducreyi present in lesions in humans and immune-competent pigs have prevented localization of these organisms within skin. However, H. ducreyi organisms were readily visualized in lesion biopsies from infected CPA-treated pigs by immunoelectron microscopy. These bacteria were extracellular and associated with necrotic host cells in the epidermis and dermis. The relative abundance of H. ducreyi in inoculated CPA-treated pig skin suggests control of bacterial replication by host immune cells during natural human infection.

Insecticidal activity of the metalloprotease AprA occurs through suppression of host cellular and humoral immunity.

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Lee, Seung Ah; Jang, Seong Han; Kim, Byung Hyun; Shibata, Toshio; Yoo, Jinwook; Jung, Yunjin; Kawabata, Shun-Ichiro; Lee, Bok Luel

2018-04-01

The biochemical characterization of virulence factors from entomopathogenic bacteria is important to understand entomopathogen-insect molecular interactions. Pseudomonas entomophila is a typical entomopathogenic bacterium that harbors virulence factors against several insects. However, the molecular actions of these factors against host innate immune responses are not clearly elucidated. In this study, we observed that bean bugs (Riptortus pedestris) that were injected with P. entomophila were highly susceptible to this bacterium. To determine how P. entomophila counteracts the host innate immunity to survive within the insect, we purified a highly enriched protein with potential host insect-killing activity from the culture supernatant of P. entomophila. Then, a 45-kDa protein was purified to homogeneity and identified as AprA which is an alkaline zinc metalloprotease of the genus Pseudomonas by liquid chromatography mass spectrometry (LC-MS). Purified AprA showed a pronounced killing effect against host insects and suppressed both host cellular and humoral innate immunity. Furthermore, to show that AprA is an important insecticidal protein of P. entomophila, we used an aprA-deficient P. entomophila mutant strain (ΔaprA). When ΔaprA mutant cells were injected to host insects, this mutant exhibited extremely attenuated virulence. In addition, the cytotoxicity against host hemocytes and the antimicrobial peptide-degrading ability of the ΔaprA mutant were greatly decreased. These findings suggest that AprA functions as an important insecticidal protein of P. entomophila via suppression of host cellular and humoral innate immune responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Salmonella Typhi Colonization Provokes Extensive Transcriptional Changes Aimed at Evading Host Mucosal Immune Defense During Early Infection of Human Intestinal Tissue

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K.P. Nickerson

2018-05-01

Full Text Available Commensal microorganisms influence a variety of host functions in the gut, including immune response, glucose homeostasis, metabolic pathways and oxidative stress, among others. This study describes how Salmonella Typhi, the pathogen responsible for typhoid fever, uses similar strategies to escape immune defense responses and survive within its human host. To elucidate the early mechanisms of typhoid fever, we performed studies using healthy human intestinal tissue samples and “mini-guts,” organoids grown from intestinal tissue taken from biopsy specimens. We analyzed gene expression changes in human intestinal specimens and bacterial cells both separately and after colonization. Our results showed mechanistic strategies that S. Typhi uses to rearrange the cellular machinery of the host cytoskeleton to successfully invade the intestinal epithelium, promote polarized cytokine release and evade immune system activation by downregulating genes involved in antigen sampling and presentation during infection. This work adds novel information regarding S. Typhi infection pathogenesis in humans, by replicating work shown in traditional cell models, and providing new data that can be applied to future vaccine development strategies. Keywords: Typhoid fever, Salmonella, Snapwell™ system, Human tissue, Terminal ileum, Immune system, Innate immunity, Immune evasion, Host-pathogen interaction, Vaccine development, Intestinal organoids, Organoid monolayer

Epithelial Cell Inflammasomes in Intestinal Immunity and Inflammation

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Andrea C. Lei-Leston

2017-09-01

Full Text Available Pattern recognition receptors (PRR, such as NOD-like receptors (NLRs, sense conserved microbial signatures, and host danger signals leading to the coordination of appropriate immune responses. Upon activation, a subset of NLR initiate the assembly of a multimeric protein complex known as the inflammasome, which processes pro-inflammatory cytokines and mediates a specialized form of cell death known as pyroptosis. The identification of inflammasome-associated genes as inflammatory bowel disease susceptibility genes implicates a role for the inflammasome in intestinal inflammation. Despite the fact that the functional importance of inflammasomes within immune cells has been well established, the contribution of inflammasome expression in non-hematopoietic cells remains comparatively understudied. Given that intestinal epithelial cells (IEC act as a barrier between the host and the intestinal microbiota, inflammasome expression by these cells is likely important for intestinal immune homeostasis. Accumulating evidence suggests that the inflammasome plays a key role in shaping epithelial responses at the host–lumen interface with many inflammasome components highly expressed by IEC. Recent studies have exposed functional roles of IEC inflammasomes in mucosal immune defense, inflammation, and tumorigenesis. In this review, we present the main features of the predominant inflammasomes and their effector mechanisms contributing to intestinal homeostasis and inflammation. We also discuss existing controversies in the field and open questions related to their implications in disease. A comprehensive understanding of the molecular basis of intestinal inflammasome signaling could hold therapeutic potential for clinical translation.

NKT cell networks in the regulation of tumor immunity.

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Robertson, Faith C; Berzofsky, Jay A; Terabe, Masaki

2014-01-01

CD1d-restricted natural killer T (NKT) cells lie at the interface between the innate and adaptive immune systems and are important mediators of immune responses and tumor immunosurveillance. These NKT cells uniquely recognize lipid antigens, and their rapid yet specific reactions influence both innate and adaptive immunity. In tumor immunity, two NKT subsets (type I and type II) have contrasting roles in which they not only cross-regulate one another, but also impact innate immune cell populations, including natural killer, dendritic, and myeloid lineage cells, as well as adaptive populations, especially CD8(+) and CD4(+) T cells. The extent to which NKT cells promote or suppress surrounding cells affects the host's ability to prevent neoplasia and is consequently of great interest for therapeutic development. Data have shown the potential for therapeutic use of NKT cell agonists and synergy with immune response modifiers in both pre-clinical studies and preliminary clinical studies. However, there is room to improve treatment efficacy by further elucidating the biological mechanisms underlying NKT cell networks. Here, we discuss the progress made in understanding NKT cell networks, their consequent role in the regulation of tumor immunity, and the potential to exploit that knowledge in a clinical setting.

Balancing immune protection and immune pathology by CD8+ T cell responses to influenza infection

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Susu eDuan

2016-02-01

Full Text Available Influenza A virus (IAV is a significant human pathogen causing annual epidemics and periodic pandemics. CD8+ cytotoxic T lymphocyte (CTL-mediated immunity contributes to clearance of virus-infected cells; CTL immunity targeting the conserved internal proteins of IAVs is a key protection mechanism when neutralizing antibodies are absent during heterosubtypic IAV infection. However, CTL infiltration into the airways, their cytotoxicity, and the effects of produced pro-inflammatory cytokines can cause severe lung tissue injury, thereby contributing to immunopathology. Studies have discovered complicated and exquisite stimulatory and inhibitory mechanisms that regulate CTL magnitude and effector activities during IAV infection. Here, we review the state of knowledge on the roles of IAV-specific CTLs in immune protection and immunopathology during IAV infection in animal models, highlighting the key findings of various requirements and constraints regulating the balance of immune protection and pathology involved in CTL immunity. We also discuss the evidence of cross-reactive CTL immunity as a positive correlate of cross-subtype protection during secondary IAV infection in both animal and human studies. We argue that the effects of CTL immunity on protection and immunopathology depend on multiple layers of host and viral factors, including complex host mechanisms to regulate CTL magnitude and effector activity, the pathogenic nature of the IAV, the innate response milieu, and the host historical immune context of influenza infection. Future efforts are needed to further understand these key host and viral factors, especially to differentiate those that constrain optimally effective CTL anti-viral immunity from those necessary to restrain CTL-mediated nonspecific immunopathology in the various contexts of IAV infection, in order to develop better vaccination and therapeutic strategies for modifying protective CTL immunity.

Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

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Ogonek, Justyna; Kralj Juric, Mateja; Ghimire, Sakhila; Varanasi, Pavankumar Reddy; Holler, Ernst; Greinix, Hildegard; Weissinger, Eva

2016-01-01

The timely reconstitution and regain of function of a donor-derived immune system is of utmost importance for the recovery and long-term survival of patients after allogeneic hematopoietic stem cell transplantation (HSCT). Of note, new developments such as umbilical cord blood or haploidentical grafts were associated with prolonged immunodeficiency due to delayed immune reconstitution, raising the need for better understanding and enhancing the process of immune reconstitution and finding strategies to further optimize these transplant procedures. Immune reconstitution post-HSCT occurs in several phases, innate immunity being the first to regain function. The slow T cell reconstitution is regarded as primarily responsible for deleterious infections with latent viruses or fungi, occurrence of graft-versus-host disease, and relapse. Here we aim to summarize the major steps of the adaptive immune reconstitution and will discuss the importance of immune balance in patients after HSCT. PMID:27909435

Mesenchymal Stem Cells (MSCs) Attenuate Cutaneous Sclerodermatous Graft-Versus-Host Disease (Scl-GVHD) through Inhibition of Immune Cell Infiltration in a Mouse Model.

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Lim, Ji-Young; Ryu, Da-Bin; Lee, Sung-Eun; Park, Gyeongsin; Min, Chang-Ki

2017-09-01

Human chronic graft-versus-host disease (GVHD) shares clinical characteristics with a murine sclerodermatous GVHD model that is characterized by skin thickening and lung fibrosis. A B10.D2 → BALB/c transplant model of sclerodermatous GVHD was used to address the therapeutic effect of mesenchymal stem cells (MSCs) on the development of chronic GVHD. The clinical and pathological severity of cutaneous sclerodermatous GVHD was significantly attenuated in MSC-treated recipients relative to sclerodermatous GVHD control subjects. After MSC treatment, skin collagen production was significantly reduced, with consistent down-regulation of Tgfb expression. Effects of MSCs on molecular markers implicated in persistent transforming growth factor-β signaling and fibrosis, such as PTEN, phosphorylated Smad-2/3, and matrix metalloproteinase-1, were observed in skin tissue. MSCs neither migrate to the skin nor affect the in vivo expansion of immune effector cells, but they inhibited the infiltration of immune effector cells into skin via down-regulation of CCR4 and CCR8 expression on CD4 + T cells and CCR1 on CD11b + monocyte/macrophages. MSCs diminished expression of chemokines such as CCL1, CCL3, CCL8, CCL17, and CCL22 in skin. MSCs were also dependent on stimulated splenocytes to suppress fibroblast proliferation. Our findings indicate that MSCs attenuate the cutaneous sclerodermatous GVHD by selectively blocking immune cell migration and down-regulating chemokines and chemokine receptors. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Expression of immune-response genes in lepidopteran host is suppressed by venom from an endoparasitoid, Pteromalus puparum

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Fang Qi

2010-09-01

Full Text Available Abstract Background The relationships between parasitoids and their insect hosts have attracted attention at two levels. First, the basic biology of host-parasitoid interactions is of fundamental interest. Second, parasitoids are widely used as biological control agents in sustainable agricultural programs. Females of the gregarious endoparasitoid Pteromalus puparum (Hymenoptera: Pteromalidae inject venom along with eggs into their hosts. P. puparum does not inject polydnaviruses during oviposition. For this reason, P. puparum and its pupal host, the small white butterfly Pieris rapae (Lepidoptera: Pieridae, comprise an excellent model system for studying the influence of an endoparasitoid venom on the biology of the pupal host. P. puparum venom suppresses the immunity of its host, although the suppressive mechanisms are not fully understood. In this study, we tested our hypothesis that P. puparum venom influences host gene expression in the two main immunity-conferring tissues, hemocytes and fat body. Results At 1 h post-venom injection, we recorded significant decreases in transcript levels of 217 EST clones (revealing 113 genes identified in silico, including 62 unknown contigs derived from forward subtractive libraries of host hemocytes and in transcript levels of 288 EST clones (221 genes identified in silico, including 123 unknown contigs from libraries of host fat body. These genes are related to insect immune response, cytoskeleton, cell cycle and apoptosis, metabolism, transport, stress response and transcriptional and translational regulation. We verified the reliability of the suppression subtractive hybridization (SSH data with semi-quantitative RT-PCR analysis of a set of randomly selected genes. This analysis showed that most of the selected genes were down-regulated after venom injection. Conclusions Our findings support our hypothesis that P. puparum venom influences gene expression in host hemocytes and fat body. Specifically

Exploiting immune cell metabolic machinery for functional HIV cure and the prevention of inflammaging

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Palmer, Clovis S.; Palchaudhuri, Riya; Albargy, Hassan; Abdel-Mohsen, Mohamed; Crowe, Suzanne M.

2018-01-01

An emerging paradigm in immunology suggests that metabolic reprogramming and immune cell activation and functions are intricately linked. Viral infections, such as HIV infection, as well as cancer force immune cells to undergo major metabolic challenges. Cells must divert energy resources in order to mount an effective immune response. However, the fact that immune cells adopt specific metabolic programs to provide host defense against intracellular pathogens and how this metabolic shift impa...

Mammalian Gut Immunity

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Chassaing, Benoit; Kumar, Manish; Baker, Mark T.; Singh, Vishal; Vijay-Kumar, Matam

2016-01-01

The mammalian intestinal tract is the largest immune organ in the body and comprises cells from non-hemopoietic (epithelia, Paneth cells, goblet cells) and hemopoietic (macrophages, dendritic cells, T-cells) origin, and is also a dwelling for trillions of microbes collectively known as the microbiota. The homeostasis of this large microbial biomass is prerequisite to maintain host health by maximizing beneficial symbiotic relationships and minimizing the risks of living in such close proximity. Both microbiota and host immune system communicate with each other to mutually maintain homeostasis in what could be called a “love–hate relationship.” Further, the host innate and adaptive immune arms of the immune system cooperate and compensate each other to maintain the equilibrium of a highly complex gut ecosystem in a stable and stringent fashion. Any imbalance due to innate or adaptive immune deficiency or aberrant immune response may lead to dysbiosis and low-grade to robust gut inflammation, finally resulting in metabolic diseases. PMID:25163502

Recombinant Marburg viruses containing mutations in the IID region of VP35 prevent inhibition of Host immune responses.

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Albariño, César G; Wiggleton Guerrero, Lisa; Spengler, Jessica R; Uebelhoer, Luke S; Chakrabarti, Ayan K; Nichol, Stuart T; Towner, Jonathan S

2015-02-01

Previous in vitro studies have demonstrated that Ebola and Marburg virus (EBOV and MARV) VP35 antagonize the host cell immune response. Moreover, specific mutations in the IFN inhibitory domain (IID) of EBOV and MARV VP35 that abrogate their interaction with virus-derived dsRNA, lack the ability to inhibit the host immune response. To investigate the role of MARV VP35 in the context of infectious virus, we used our reverse genetics system to generate two recombinant MARVs carrying specific mutations in the IID region of VP35. Our data show that wild-type and mutant viruses grow to similar titers in interferon deficient cells, but exhibit attenuated growth in interferon-competent cells. Furthermore, in contrast to wild-type virus, both MARV mutants were unable to inhibit expression of various antiviral genes. The MARV VP35 mutants exhibit similar phenotypes to those previously described for EBOV, suggesting the existence of a shared immune-modulatory strategy between filoviruses. Published by Elsevier Inc.

Dynamic Fungal Cell Wall Architecture in Stress Adaptation and Immune Evasion.

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Hopke, Alex; Brown, Alistair J P; Hall, Rebecca A; Wheeler, Robert T

2018-04-01

Deadly infections from opportunistic fungi have risen in frequency, largely because of the at-risk immunocompromised population created by advances in modern medicine and the HIV/AIDS pandemic. This review focuses on dynamics of the fungal polysaccharide cell wall, which plays an outsized role in fungal pathogenesis and therapy because it acts as both an environmental barrier and as the major interface with the host immune system. Human fungal pathogens use architectural strategies to mask epitopes from the host and prevent immune surveillance, and recent work elucidates how biotic and abiotic stresses present during infection can either block or enhance masking. The signaling components implicated in regulating fungal immune recognition can teach us how cell wall dynamics are controlled, and represent potential targets for interventions designed to boost or dampen immunity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural modifications of bacterial lipopolysaccharide that facilitate Gram-negative bacteria evasion of host innate immunity

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Motohiro eMatsuura

2013-05-01

Full Text Available Bacterial lipopolysaccharide (LPS, a cell wall component characteristic of Gram-negative bacteria, is a representative pathogen-associated molecular pattern that allows mammalian cells to recognize bacterial invasion and trigger innate immune responses. The polysaccharide moiety of LPS primary plays protective roles for bacteria such as prevention from complement attacks or camouflage with common host carbohydrate residues. The lipid moiety, termed lipid A, is recognized by the Toll-like receptor 4 (TLR4/MD-2 complex, which transduces signals for activation of host innate immunity. The basic structure of lipid A is a glucosamine disaccharide substituted by phosphate groups and acyl groups. Lipid A with 6 acyl groups (hexa-acylated form has been indicated to be a strong stimulator of the TLR4/MD-2 complex. This type of lipid A is conserved among a wide variety of Gram-negative bacteria, and those bacteria are easily recognized by host cells for activation of defensive innate immune responses. Modifications of the lipid A structure to less-acylated forms have been observed in some bacterial species, and those forms are poor stimulators of the TLR4/MD-2 complex. Such modifications are thought to facilitate bacterial evasion of host innate immunity, thereby enhancing pathogenicity. This hypothesis is supported by studies of Yersinia pestis LPS, which contains hexa-acylated lipid A when the bacterium grows at 27ºC (the temperature of the vector flea, and shifts to contain less-acylated forms when grown at the human body temperature of 37ºC. This alteration of lipid A forms following transmission of Y. pestis from fleas to humans contributes predominantly to the virulence of this bacterium over other virulence factors. A similar role for less-acylated lipid A forms has been indicated in some other bacterial species, such as Francisella tularensis, Helicobacter pylori, and Porphyromonas gingivalis, and further studies to explore this concept are

Immunity and Tolerance Induced by Intestinal Mucosal Dendritic Cells

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Julio Aliberti

2016-01-01

Full Text Available Dendritic cells present in the digestive tract are constantly exposed to environmental antigens, commensal flora, and invading pathogens. Under steady-state conditions, these cells have high tolerogenic potential, triggering differentiation of regulatory T cells to protect the host from unwanted proinflammatory immune responses to innocuous antigens or commensals. On the other hand, these cells must discriminate between commensal flora and invading pathogens and mount powerful immune response against pathogens. A potential result of unbalanced tolerogenic versus proinflammatory responses mediated by dendritic cells is associated with chronic inflammatory conditions, such as Crohn’s disease, ulcerative colitis, food allergies, and celiac disease. Herein, we review the dendritic cell population involved in mediating tolerance and immunity in mucosal surfaces, the progress in unveiling their development in vivo, and factors that can influence their functions.

Role of Neurochemicals in the Interaction between the Microbiota and the Immune and the Nervous System of the Host Organism.

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Oleskin, Alexander V; Shenderov, Boris A; Rogovsky, Vladimir S

2017-09-01

This work is concerned with the role of evolutionary conserved substances, neurotransmitters, and neurohormones, within the complex framework of the microbial consortium-immune system-nervous system axis in the human or animal organism. Although the operation of each of these systems per se is relatively well understood, their combined effects on the host organism still await further research. Drawing on recent research on host-produced and microbial low-molecular-weight neurochemicals such as biogenic amines, amino acids, and short-chain fatty acids (SCFAs), we suggest that these mediators form a part of a universal neurochemical "language." It mediates the whole gamut of harmonious and disharmonious interactions between (a) the intestinal microbial consortium, (b) local and systemic immune cells, and (c) the central and peripheral nervous system. Importantly, the ongoing microbiota-host interactivity is bidirectional. We present evidence that a large number of microbially produced low-molecular-weight compounds are identical or homologous to mediators that are synthesized by immune or nervous cells and, therefore, can bind to the corresponding host receptors. In addition, microbial cells specifically respond to host-produced neuromediators/neurohormones because they have adapted to them during the course of many millions of years of microbiota-host coevolution. We emphasize that the terms "microbiota" and "microbial consortium" are to be used in the broadest sense, so as to include, apart from bacteria, also eukaryotic microorganisms. These are exemplified by the mycobiota whose role in the microbial consortium-immune system-nervous system axis researchers are only beginning to elucidate. In light of the above, it is imperative to reform the current strategies of using probiotic microorganisms and their metabolites for treating and preventing dysbiosis-related diseases. The review demonstrates, in the example of novel probiotics (psychobiotics), that many target

Bifidobacterial surface-exopolysaccharide facilitates commensal-host interaction through immune modulation and pathogen protection

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Fanning, Saranna; Hall, Lindsay J.; Cronin, Michelle; Zomer, Aldert; MacSharry, John; Goulding, David; O'Connell Motherway, Mary; Shanahan, Fergus; Nally, Kenneth; Dougan, Gordon; van Sinderen, Douwe

2012-01-01

Bifidobacteria comprise a significant proportion of the human gut microbiota. Several bifidobacterial strains are currently used as therapeutic interventions, claiming various health benefits by acting as probiotics. However, the precise mechanisms by which they maintain habitation within their host and consequently provide these benefits are not fully understood. Here we show that Bifidobacterium breve UCC2003 produces a cell surface-associated exopolysaccharide (EPS), the biosynthesis of which is directed by either half of a bidirectional gene cluster, thus leading to production of one of two possible EPSs. Alternate transcription of the two opposing halves of this cluster appears to be the result of promoter reorientation. Surface EPS provided stress tolerance and promoted in vivo persistence, but not initial colonization. Marked differences were observed in host immune response: strains producing surface EPS (EPS+) failed to elicit a strong immune response compared with EPS-deficient variants. Specifically, EPS production was shown to be linked to the evasion of adaptive B-cell responses. Furthermore, presence of EPS+ B. breve reduced colonization levels of the gut pathogen Citrobacter rodentium. Our data thus assigns a pivotal and beneficial role for EPS in modulating various aspects of bifidobacterial–host interaction, including the ability of commensal bacteria to remain immunologically silent and in turn provide pathogen protection. This finding enforces the probiotic concept and provides mechanistic insights into health-promoting benefits for both animal and human hosts. PMID:22308390

A Trematode Parasite Derived Growth Factor Binds and Exerts Influences on Host Immune Functions via Host Cytokine Receptor Complexes.

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Azad A Sulaiman

2016-11-01

Full Text Available The trematode Fasciola hepatica is responsible for chronic zoonotic infection globally. Despite causing a potent T-helper 2 response, it is believed that potent immunomodulation is responsible for rendering this host reactive non-protective host response thereby allowing the parasite to remain long-lived. We have previously identified a growth factor, FhTLM, belonging to the TGF superfamily can have developmental effects on the parasite. Herein we demonstrate that FhTLM can exert influence over host immune functions in a host receptor specific fashion. FhTLM can bind to receptor members of the Transforming Growth Factor (TGF superfamily, with a greater affinity for TGF-β RII. Upon ligation FhTLM initiates the Smad2/3 pathway resulting in phenotypic changes in both fibroblasts and macrophages. The formation of fibroblast CFUs is reduced when cells are cultured with FhTLM, as a result of TGF-β RI kinase activity. In parallel the wound closure response of fibroblasts is also delayed in the presence of FhTLM. When stimulated with FhTLM blood monocyte derived macrophages adopt an alternative or regulatory phenotype. They express high levels interleukin (IL-10 and arginase-1 while displaying low levels of IL-12 and nitric oxide. Moreover they also undergo significant upregulation of the inhibitory receptor PD-L1 and the mannose receptor. Use of RNAi demonstrates that this effect is dependent on TGF-β RII and mRNA knock-down leads to a loss of IL-10 and PD-L1. Finally, we demonstrate that FhTLM aids newly excysted juveniles (NEJs in their evasion of antibody-dependent cell cytotoxicity (ADCC by reducing the NO response of macrophages-again dependent on TGF-β RI kinase. FhTLM displays restricted expression to the F. hepatica gut resident NEJ stages. The altered fibroblast responses would suggest a role for dampened tissue repair responses in facilitating parasite migration. Furthermore, the adoption of a regulatory macrophage phenotype would allow

Stromal cell contributions to the homeostasis and functionality of the immune system.

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Mueller, Scott N; Germain, Ronald N

2009-09-01

A defining characteristic of the immune system is the constant movement of many of its constituent cells through the secondary lymphoid tissues, mainly the spleen and lymph nodes, where crucial interactions that underlie homeostatic regulation, peripheral tolerance and the effective development of adaptive immune responses take place. What has only recently been recognized is the role that non-haematopoietic stromal elements have in many aspects of immune cell migration, activation and survival. In this Review, we summarize our current understanding of lymphoid compartment stromal cells, examine their possible heterogeneity, discuss how these cells contribute to immune homeostasis and the efficient initiation of adaptive immune responses, and highlight how targeting of these elements by some pathogens can influence the host immune response.

Simultaneous transcriptional profiling of bacteria and their host cells.

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Michael S Humphrys

Full Text Available We developed an RNA-Seq-based method to simultaneously capture prokaryotic and eukaryotic expression profiles of cells infected with intracellular bacteria. As proof of principle, this method was applied to Chlamydia trachomatis-infected epithelial cell monolayers in vitro, successfully obtaining transcriptomes of both C. trachomatis and the host cells at 1 and 24 hours post-infection. Chlamydiae are obligate intracellular bacterial pathogens that cause a range of mammalian diseases. In humans chlamydiae are responsible for the most common sexually transmitted bacterial infections and trachoma (infectious blindness. Disease arises by adverse host inflammatory reactions that induce tissue damage & scarring. However, little is known about the mechanisms underlying these outcomes. Chlamydia are genetically intractable as replication outside of the host cell is not yet possible and there are no practical tools for routine genetic manipulation, making genome-scale approaches critical. The early timeframe of infection is poorly understood and the host transcriptional response to chlamydial infection is not well defined. Our simultaneous RNA-Seq method was applied to a simplified in vitro model of chlamydial infection. We discovered a possible chlamydial strategy for early iron acquisition, putative immune dampening effects of chlamydial infection on the host cell, and present a hypothesis for Chlamydia-induced fibrotic scarring through runaway positive feedback loops. In general, simultaneous RNA-Seq helps to reveal the complex interplay between invading bacterial pathogens and their host mammalian cells and is immediately applicable to any bacteria/host cell interaction.

Inhibition of host cell translation elongation by Legionella pneumophila blocks the host cell unfolded protein response.

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Hempstead, Andrew D; Isberg, Ralph R

2015-12-08

Cells of the innate immune system recognize bacterial pathogens by detecting common microbial patterns as well as pathogen-specific activities. One system that responds to these stimuli is the IRE1 branch of the unfolded protein response (UPR), a sensor of endoplasmic reticulum (ER) stress. Activation of IRE1, in the context of Toll-like receptor (TLR) signaling, induces strong proinflammatory cytokine induction. We show here that Legionella pneumophila, an intravacuolar pathogen that replicates in an ER-associated compartment, blocks activation of the IRE1 pathway despite presenting pathogen products that stimulate this response. L. pneumophila TLR ligands induced the splicing of mRNA encoding XBP1s, the main target of IRE1 activity. L. pneumophila was able to inhibit both chemical and bacterial induction of XBP1 splicing via bacterial translocated proteins that interfere with host protein translation. A strain lacking five translocated translation elongation inhibitors was unable to block XBP1 splicing, but this could be rescued by expression of a single such inhibitor, consistent with limitation of the response by translation elongation inhibitors. Chemical inhibition of translation elongation blocked pattern recognition receptor-mediated XBP1 splicing, mimicking the effects of the bacterial translation inhibitors. In contrast, host cell-promoted inhibition of translation initiation in response to the pathogen was ineffective in blocking XBP1 splicing, demonstrating the need for the elongation inhibitors for protection from the UPR. The inhibition of host translation elongation may be a common strategy used by pathogens to limit the innate immune response by interfering with signaling via the UPR.

Systems biology of host-mycobiota interactions: dissecting Dectin-1 and Dectin-2 signalling in immune cells with DC-ATLAS.

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Rizzetto, Lisa; De Filippo, Carlotta; Rivero, Damariz; Riccadonna, Samantha; Beltrame, Luca; Cavalieri, Duccio

2013-11-01

Modelling the networks sustaining the fruitful coexistence between fungi and their mammalian hosts is becoming increasingly important to control emerging fungal pathogens. The C-type lectins Dectin-1 and Dectin-2 are involved in host defense mechanisms against fungal infection driving inflammatory and adaptive immune responses and complement in containing fungal burdens. Recognizing carbohydrate structures in pathogens, their engagement induces maturation of dendritic cells (DCs) into potent immuno-stimulatory cells endowed with the capacity to efficiently prime T cells. Owing to these properties, Dectin-1 and Dectin-2 agonists are currently under investigation as promising adjuvants in vaccination procedures for the treatment of fungal infection. Thus, a detailed understanding of events' cascade specifically triggered in DCs upon engagement is of great interest in translational research. Here, we summarize the current knowledge on Dectin-1 and Dectin-2 signalling in DCs highlighting similarities and differences. Detailed maps are annotated, using the Biological Connection Markup Language (BCML) data model, and stored in DC-ATLAS, a versatile resource for the interpretation of high-throughput data generated perturbing the signalling network of DCs. Copyright © 2013 Elsevier GmbH. All rights reserved.

Diet and host-microbial crosstalk in postnatal intestinal immune homeostasis.

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Jain, Nitya; Walker, W Allan

2015-01-01

Neonates face unique challenges in the period following birth. The postnatal immune system is in the early stages of development and has a range of functional capabilities that are distinct from the mature adult immune system. Bidirectional immune-microbial interactions regulate the development of mucosal immunity and alter the composition of the microbiota, which contributes to overall host well-being. In the past few years, nutrition has been highlighted as a third element in this interaction that governs host health by modulating microbial composition and the function of the immune system. Dietary changes and imbalances can disturb the immune-microbiota homeostasis, which might alter susceptibility to several autoimmune and metabolic diseases. Major changes in cultural traditions, socioeconomic status and agriculture are affecting the nutritional status of humans worldwide, which is altering core intestinal microbial communities. This phenomenon is especially relevant to the neonatal and paediatric populations, in which the microbiota and immune system are extremely sensitive to dietary influences. In this Review, we discuss the current state of knowledge regarding early-life nutrition, its effects on the microbiota and the consequences of diet-induced perturbation of the structure of the microbial community on mucosal immunity and disease susceptibility.

Mucosal innate immune cells regulate both gut homeostasis and intestinal inflammation.

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Kurashima, Yosuke; Goto, Yoshiyuki; Kiyono, Hiroshi

2013-12-01

Continuous exposure of intestinal mucosal surfaces to diverse microorganisms and their metabolites reflects the biological necessity for a multifaceted, integrated epithelial and immune cell-mediated regulatory system. The development and function of the host cells responsible for the barrier function of the intestinal surface (e.g., M cells, Paneth cells, goblet cells, and columnar epithelial cells) are strictly regulated through both positive and negative stimulation by the luminal microbiota. Stimulation by damage-associated molecular patterns and commensal bacteria-derived microbe-associated molecular patterns provokes the assembly of inflammasomes, which are involved in maintaining the integrity of the intestinal epithelium. Mucosal immune cells located beneath the epithelium play critical roles in regulating both the mucosal barrier and the relative composition of the luminal microbiota. Innate lymphoid cells and mast cells, in particular, orchestrate the mucosal regulatory system to create a mutually beneficial environment for both the host and the microbiota. Disruption of mucosal homeostasis causes intestinal inflammation such as that seen in inflammatory bowel disease. Here, we review the recent research on the biological interplay among the luminal microbiota, epithelial cells, and mucosal innate immune cells in both healthy and pathological conditions. © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Patterns of early gut colonization shape future immune responses of the host

DEFF Research Database (Denmark)

Hansen, Camilla Hartmann Friis; Nielsen, Dennis Sandris; Kverka, Miloslav

2012-01-01

The most important trigger for immune system development is the exposure to microbial components immediately after birth. Moreover, targeted manipulation of the microbiota can be used to change host susceptibility to immune-mediated diseases. Our aim was to analyze how differences in early gut...... production. In conclusion, a time window exists that enables the artificial colonization of GF mice by a single oral dose of caecal content, which may modify the future immune phenotype of the host. Moreover, delayed microbial colonization of the gut causes permanent changes in the immune system....

FTY720 ameliorates murine sclerodermatous chronic graft-versus-host disease by promoting expansion of splenic regulatory cells and inhibiting immune cell infiltration into skin.

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Huu, Doanh Le; Matsushita, Takashi; Jin, Guihua; Hamaguchi, Yasuhito; Hasegawa, Minoru; Takehara, Kazuhiko; Fujimoto, Manabu

2013-06-01

Sphingosine 1-phosphate (S1P) exerts a variety of activities in immune, inflammatory, and vascular systems. S1P plays an important role in systemic sclerosis (SSc) pathogenesis. Regulation of S1P in fibrotic diseases as well as in SSc was recently reported. FTY720, an oral S1P receptor modulator, has been shown to be a useful agent for the prevention of transplant rejection and autoimmune diseases. Murine sclerodermatous chronic graft-versus-host disease (GVHD) is a model for human sclerodermatous chronic GVHD and SSc. We undertook this study to investigate the effects of FTY720 in murine sclerodermatous chronic GVHD. FTY720 was orally administered to allogeneic recipient mice from day 0 to day 20 (short-term, early-treatment group), from day 0 to day 42 (full-term, early-treatment group), or from day 22 to day 42 (delayed-treatment group) after bone marrow transplantation. Delayed administration of FTY720 attenuated, and early administration of FTY720 inhibited, the severity and fibrosis in murine sclerodermatous chronic GVHD. With early treatment, FTY720 induced expansion of splenic myeloid-derived suppressor cells, Treg cells, and Breg cells. Vascular damage in chronic GVHD was inhibited by FTY720 through down-regulating serum levels of S1P and soluble E-selectin. FTY720 inhibited infiltration of immune cells into skin. Moreover, FTY720 diminished the expression of messenger RNA for monocyte chemotactic protein 1, macrophage inflammatory protein 1α, RANTES, tumor necrosis factor α, interferon-γ, interleukin-6 (IL-6), IL-10, IL-17A, and transforming growth factor β1 in the skin. FTY720 suppressed the immune response by promoting the expansion of regulatory cells and reducing vascular damage and infiltration of immune cells into the skin. Taken together, these results have important implications for the potential use of FTY720 in the treatment of sclerodermatous chronic GVHD and SSc in humans. Copyright © 2013 by the American College of Rheumatology.

Functions of innate immune cells and commensal bacteria in gut homeostasis.

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Kayama, Hisako; Takeda, Kiyoshi

2016-02-01

The intestinal immune system remains unresponsive to beneficial microbes and dietary antigens while activating pro-inflammatory responses against pathogens for host defence. In intestinal mucosa, abnormal activation of innate immunity, which directs adaptive immune responses, causes the onset and/or progression of inflammatory bowel diseases. Thus, innate immunity is finely regulated in the gut. Multiple innate immune cell subsets have been identified in both murine and human intestinal lamina propria. Some innate immune cells play a key role in the maintenance of gut homeostasis by preventing inappropriate adaptive immune responses while others are associated with the pathogenesis of intestinal inflammation through development of Th1 and Th17 cells. In addition, intestinal microbiota and their metabolites contribute to the regulation of innate/adaptive immune responses. Accordingly, perturbation of microbiota composition can trigger intestinal inflammation by driving inappropriate immune responses. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

How Human Papillomavirus Replication and Immune Evasion Strategies Take Advantage of the Host DNA Damage Repair Machinery.

Science.gov (United States)

Bordignon, Valentina; Di Domenico, Enea Gino; Trento, Elisabetta; D'Agosto, Giovanna; Cavallo, Ilaria; Pontone, Martina; Pimpinelli, Fulvia; Mariani, Luciano; Ensoli, Fabrizio

2017-12-19

The DNA damage response (DDR) is a complex signalling network activated when DNA is altered by intrinsic or extrinsic agents. DDR plays important roles in genome stability and cell cycle regulation, as well as in tumour transformation. Viruses have evolved successful life cycle strategies in order to ensure a chronic persistence in the host, virtually avoiding systemic sequelae and death. This process promotes the periodic shedding of large amounts of infectious particles to maintain a virus reservoir in individual hosts, while allowing virus spreading within the community. To achieve such a successful lifestyle, the human papilloma virus (HPV) needs to escape the host defence systems. The key to understanding how this is achieved is in the virus replication process that provides by itself an evasion mechanism by inhibiting and delaying the host immune response against the viral infection. Numerous studies have demonstrated that HPV exploits both the ataxia-telangiectasia mutated (ATM) and ataxia-telangiectasia and rad3-related (ATR) DDR pathways to replicate its genome and maintain a persistent infection by downregulating the innate and cell-mediated immunity. This review outlines how HPV interacts with the ATM- and ATR-dependent DDR machinery during the viral life cycle to create an environment favourable to viral replication, and how the interaction with the signal transducers and activators of transcription (STAT) protein family and the deregulation of the Janus kinase (JAK)-STAT pathways may impact the expression of interferon-inducible genes and the innate immune responses.

Genome wide transcriptome profiling of a murine acute melioidosis model reveals new insights into how Burkholderia pseudomallei overcomes host innate immunity

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Nathan Sheila

2010-11-01

Full Text Available Abstract Background At present, very little is known about how Burkholderia pseudomallei (B. pseudomallei interacts with its host to elicit melioidosis symptoms. We established a murine acute-phase melioidosis model and used DNA microarray technology to investigate the global host/pathogen interaction. We compared the transcriptome of infected liver and spleen with uninfected tissues over an infection period of 42 hr to identify genes whose expression is altered in response to an acute infection. Results Viable B. pseudomallei cells were consistently detected in the blood, liver and spleen during the 42 hr course of infection. Microarray analysis of the liver and spleen over this time course demonstrated that genes involved in immune response, stress response, cell cycle regulation, proteasomal degradation, cellular metabolism and signal transduction pathways were differentially regulated. Up regulation of toll-like receptor 2 (TLR2 gene expression suggested that a TLR2-mediated signalling pathway is responsible for recognition and initiation of an inflammatory response to the acute B. pseudomallei infection. Most of the highly elevated inflammatory genes are a cohort of "core host immune response" genes commonly seen in general inflammation infections. Concomitant to this initial inflammatory response, we observed an increase in transcripts associated with cell-death, caspase activation and peptidoglysis that ultimately promote tissue injury in the host. The complement system responsible for restoring host cellular homeostasis and eliminating intracellular bacteria was activated only after 24 hr post-infection. However, at this time point, diverse host nutrient metabolic and cellular pathways including glycolysis, fatty acid metabolism and tricarboxylic acid (TCA cycle were repressed. Conclusions This detailed picture of the host transcriptional response during acute melioidosis highlights a broad range of innate immune mechanisms that are

Small non-coding RNAs: new insights in modulation of host immune response by intracellular bacterial pathogens

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Waqas Ahmed

2016-10-01

Full Text Available Pathogenic bacteria possess intricate regulatory networks that temporally control the production of virulence factors, and enable the bacteria to survive and proliferate within host cell. Small non-coding RNAs (sRNAs have been identified as important regulators of gene expression in diverse biological contexts. Recent research has shown bacterial sRNAs involved in growth and development, cell proliferation, differentiation, metabolism, cell signaling and immune response through regulating protein–protein interactions or via their ability to base pair with RNA and DNA. In this review, we provide a brief overview of mechanism of action employed by immune-related sRNAs, their known functions in immunity, and how they can be integrated into regulatory circuits that govern virulence, which will facilitates to understand pathogenesis and the development of novel, more effective therapeutic approaches to treat infections caused by intracellular bacterial pathogens.

Mechanisms of Host-Pathogen Protein Complex Formation and Bacterial Immune Evasion of Streptococcus suis Protein Fhb.

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Li, Xueqin; Liu, Peng; Gan, Shuzhen; Zhang, Chunmao; Zheng, Yuling; Jiang, Yongqiang; Yuan, Yuan

2016-08-12

Streptococcus suis serotype 2 (S. suis 2)-induced sepsis and meningitis are often accompanied by bacteremia. The evasion of polymorphonuclear leukocyte-mediated phagocytic clearance is central to the establishment of bacteremia caused by S. suis 2 and is facilitated by the ability of factor H (FH)-binding protein (Fhb) to bind FH on the bacterial surface, thereby impeding alternative pathway complement activation and phagocytic clearance. Here, C3b/C3d was found to bind to Fhb, along with FH, forming a large immune complex. The formation of this immune complex was mediated by domain II of Fhb via electrostatic and hydrophobic interactions, which, to our knowledge, is a new type of interaction. Interestingly, Fhb was found to be associated with the cell envelope and also present in the culture supernatant, where secreted Fhb inhibited complement activation via interactions with domain II, thereby enhancing antiphagocytic clearance by polymorphonuclear leukocytes. Thus, Fhb is a multifunctional bacterial protein, which binds host complement component C3 as well as FH and interferes with innate immune recognition in a secret protein manner. S. suis 2 therefore appears to have developed a new strategy to combat host innate immunity and enhance survival in host blood. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Mechanisms of Host-Pathogen Protein Complex Formation and Bacterial Immune Evasion of Streptococcus suis Protein Fhb*

Science.gov (United States)

Li, Xueqin; Liu, Peng; Gan, Shuzhen; Zhang, Chunmao; Zheng, Yuling; Jiang, Yongqiang; Yuan, Yuan

2016-01-01

Streptococcus suis serotype 2 (S. suis 2)-induced sepsis and meningitis are often accompanied by bacteremia. The evasion of polymorphonuclear leukocyte-mediated phagocytic clearance is central to the establishment of bacteremia caused by S. suis 2 and is facilitated by the ability of factor H (FH)-binding protein (Fhb) to bind FH on the bacterial surface, thereby impeding alternative pathway complement activation and phagocytic clearance. Here, C3b/C3d was found to bind to Fhb, along with FH, forming a large immune complex. The formation of this immune complex was mediated by domain II of Fhb via electrostatic and hydrophobic interactions, which, to our knowledge, is a new type of interaction. Interestingly, Fhb was found to be associated with the cell envelope and also present in the culture supernatant, where secreted Fhb inhibited complement activation via interactions with domain II, thereby enhancing antiphagocytic clearance by polymorphonuclear leukocytes. Thus, Fhb is a multifunctional bacterial protein, which binds host complement component C3 as well as FH and interferes with innate immune recognition in a secret protein manner. S. suis 2 therefore appears to have developed a new strategy to combat host innate immunity and enhance survival in host blood. PMID:27342778

Efficacy of multiple anticancer therapies may depend on host immune response

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Kritika Karri

2017-06-01

Full Text Available The host immune system is a key player in anticancer therapy response and resistance. Although the impact of host immune response in the ‘war against cancer’ has been studied and it has been the basis for immunotherapy, understanding of its role in attenuating the action of conventional anticancer therapies is an area that has not been fully explored. In spite of advances in systemic therapy, the 5-year survival rate for adenocarcinoma is still a mere 13% and the primary reason for treatment failure is believed to be due to acquired resistance to therapy. Hence, there is a need for identifying reliable biomarkers for guided treatment of lung and colon adenocarcinoma and to better predict the outcomes of specific anticancer therapies. In this work, gene expression data were analyzed using public resources and this study shows how host immune competence underscores the efficacy of various anticancer therapies. Additionally, the result provides insight on the regulation of certain biochemical pathways relating to the immune system, and suggests that smart chemotherapeutic intervention strategies could be based on a patient’s immune profile.

Rapamycin delays growth of Wnt-1 tumors in spite of suppression of host immunity

International Nuclear Information System (INIS)

Svirshchevskaya, Elena V; Mariotti, Jacopo; Wright, Mollie H; Viskova, Natalia Y; Telford, William; Fowler, Daniel H; Varticovski, Lyuba

2008-01-01

Rapamycin, an inhibitor of mammalian target of Rapamycin (mTOR), is an immunosuppressive agent that has anti-proliferative effects on some tumors. However, the role of Rapamycin-induced immune suppression on tumor progression has not been examined. We developed a transplantation model for generation of mammary tumors in syngeneic recipients that can be used to address the role of the immune system on tumor progression. We examined the effect of Rapamycin on the immune system and growth of MMTV-driven Wnt-1 mammary tumors which were transplanted into irradiated and bone marrow-reconstituted, or naïve mice. Rapamycin induced severe immunosuppression and significantly delayed the growth of Wnt-1 tumors. T cell depletion in spleen and thymus and reduction in T cell cytokine secretion were evident within 7 days of therapy. By day 20, splenic but not thymic T cell counts, and cytokine secretion recovered. We determined whether adoptive T cell therapy enhances the anti-cancer effect using ex vivo generated Rapamycin-resistant T cells. However, T cell transfer during Rapamycin therapy did not improve the outcome relative to drug therapy alone. Thus, we could not confirm that suppression of T cell immunity contributes to tumor growth in this model. Consistent with suppression of the mTOR pathway, decreased 4E-BP1, p70 S6-kinase, and S6 protein phosphorylation correlated with a decrease in Wnt-1 tumor cell proliferation. Rapamycin has a direct anti-tumor effect on Wnt-1 breast cancer in vivo that involves inhibition of the mTOR pathway at doses that also suppress host immune responses

Glycan gimmickry by parasitic helminths: a strategy for modulating the host immune response?

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van Die, Irma; Cummings, Richard D

2010-01-01

Parasitic helminths (worms) co-evolved with vertebrate immune systems to enable long-term survival of worms in infected hosts. Among their survival strategies, worms use their glycans within glycoproteins and glycolipids, which are abundant on helminth surfaces and in their excretory/ secretory products, to regulate and suppress host immune responses. Many helminths express unusual and antigenic (nonhost-like) glycans, including those containing polyfucose, tyvelose, terminal GalNAc, phosphorylcholine, methyl groups, and sugars in unusual linkages. In addition, some glycan antigens are expressed that share structural features with those in their intermediate and vertebrate hosts (host-like glycans), including Le(X) (Galbeta1-4[Fucalpha1-3]GlcNAc-), LDNF (GalNAcbeta1-4[Fucalpha1-3]GlcNAc-), LDN (GalNAcbeta1-4GlcNAc-), and Tn (GalNAcalpha1-O-Thr/Ser) antigens. The expression of host-like glycan determinants is remarkable and suggests that helminths may gain advantages by synthesizing such glycans. The expression of host-like glycans by parasites previously led to the concept of "molecular mimicry," in which molecules are either derived from the pathogen or acquired from the host to evade recognition by the host immune system. However, recent discoveries into the potential of host glycan-binding proteins (GBPs), such as C-type lectin receptors and galectins, to functionally interact with various host-like helminth glycans provide new insights. Host GBPs through their interactions with worm-derived glycans participate in shaping innate and adaptive immune responses upon infection. We thus propose an alternative concept termed "glycan gimmickry," which is defined as an active strategy of parasites to use their glycans to target GBPs within the host to promote their survival.

Multiple factors and processes involved in host cell killing by bacteriophage Mu: characterization and mapping.

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Waggoner, B T; Marrs, C F; Howe, M M; Pato, M L

1984-07-15

The regions of bacteriophage Mu involved in host cell killing were determined by infection of a lambda-immune host with 12 lambda pMu-transducing phages carrying different amounts of Mu DNA beginning at the left end. Infecting lambda pMu phages containing 5.0 (+/- 0.2) kb or less of the left end of Mu DNA did not kill the lambda-immune host, whereas lambda pMu containing 5.1 kb did kill, thus locating the right end of the kil gene between approximately 5.0 and 5.1 kb. For the Kil+ phages the extent of killing increased as the multiplicity of infection (m.o.i.) increased. In addition, killing was also affected by the presence of at least two other regions of Mu DNA: one, located between 5.1 and 5.8 kb, decreased the extent of killing; the other, located between 6.3 and 7.9 kb, greatly increased host cell killing. Killing was also assayed after lambda pMu infection of a lambda-immune host carrying a mini-Mu deleted for most of the B gene and the middle region of Mu DNA. Complementation of mini-Mu replication by infecting B+ lambda pMu phages resulted in killing of the lambda-immune, mini-Mu-containing host, regardless of the presence or absence of the Mu kil gene. The extent of host cell killing increased as the m.o.i. of the infecting lambda pMu increased, and was further enhanced by both the presence of the kil gene and the region located between 6.3 and 7.9 kb. These distinct processes of kil-mediated killing in the absence of replication and non-kil-mediated killing in the presence of replication were also observed after induction of replication-deficient and kil mutant prophages, respectively.

Microbiota promote secretory cell determination in the intestinal epithelium by modulating host Notch signaling.

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Troll, Joshua V; Hamilton, M Kristina; Abel, Melissa L; Ganz, Julia; Bates, Jennifer M; Stephens, W Zac; Melancon, Ellie; van der Vaart, Michiel; Meijer, Annemarie H; Distel, Martin; Eisen, Judith S; Guillemin, Karen

2018-02-23

Resident microbes promote many aspects of host development, although the mechanisms by which microbiota influence host tissues remain unclear. We showed previously that the microbiota is required for allocation of appropriate numbers of secretory cells in the zebrafish intestinal epithelium. Because Notch signaling is crucial for secretory fate determination, we conducted epistasis experiments to establish whether the microbiota modulates host Notch signaling. We also investigated whether innate immune signaling transduces microbiota cues via the Myd88 adaptor protein. We provide the first evidence that microbiota-induced, Myd88-dependent signaling inhibits host Notch signaling in the intestinal epithelium, thereby promoting secretory cell fate determination. These results connect microbiota activity via innate immune signaling to the Notch pathway, which also plays crucial roles in intestinal homeostasis throughout life and when impaired can result in chronic inflammation and cancer. © 2018. Published by The Company of Biologists Ltd.

Regulation of intestinal homeostasis by innate immune cells.

Science.gov (United States)

Kayama, Hisako; Nishimura, Junichi; Takeda, Kiyoshi

2013-12-01

The intestinal immune system has an ability to distinguish between the microbiota and pathogenic bacteria, and then activate pro-inflammatory pathways against pathogens for host defense while remaining unresponsive to the microbiota and dietary antigens. In the intestine, abnormal activation of innate immunity causes development of several inflammatory disorders such as inflammatory bowel diseases (IBD). Thus, activity of innate immunity is finely regulated in the intestine. To date, multiple innate immune cells have been shown to maintain gut homeostasis by preventing inadequate adaptive immune responses in the murine intestine. Additionally, several innate immune subsets, which promote Th1 and Th17 responses and are implicated in the pathogenesis of IBD, have recently been identified in the human intestinal mucosa. The demonstration of both murine and human intestinal innate immune subsets contributing to regulation of adaptive immunity emphasizes the conserved innate immune functions across species and might promote development of the intestinal innate immunity-based clinical therapy.

Impact of Nosema ceranae and Nosema apis on individual worker bees of the two host species (Apis cerana and Apis mellifera) and regulation of host immune response.

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Sinpoo, Chainarong; Paxton, Robert J; Disayathanoowat, Terd; Krongdang, Sasiprapa; Chantawannakul, Panuwan

Nosema apis and Nosema ceranae are obligate intracellular microsporidian parasites infecting midgut epithelial cells of host adult honey bees, originally Apis mellifera and Apis cerana respectively. Each microsporidia cross-infects the other host and both microsporidia nowadays have a worldwide distribution. In this study, cross-infection experiments using both N. apis and N. ceranae in both A. mellifera and A. cerana were carried out to compare pathogen proliferation and impact on hosts, including host immune response. Infection by N. ceranae led to higher spore loads than by N. apis in both host species, and there was greater proliferation of microsporidia in A. mellifera compared to A. cerana. Both N. apis and N. ceranae were pathogenic in both host Apis species. N. ceranae induced subtly, though not significantly, higher mortality than N. apis in both host species, yet survival of A. cerana was no different to that of A. mellifera in response to N. apis or N. ceranae. Infections of both host species with N. apis and N. ceranae caused significant up-regulation of AMP genes and cellular mediated immune genes but did not greatly alter apoptosis-related gene expression. In this study, A. cerana enlisted a higher immune response and displayed lower loads of N. apis and N. ceranae spores than A. mellifera, suggesting it may be better able to defend itself against microsporidia infection. We caution against over-interpretation of our results, though, because differences between host and parasite species in survival were insignificant and because size differences between microsporidia species and between host Apis species may alternatively explain the differential proliferation of N. ceranae in A. mellifera. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dual oxidase in mucosal immunity and host-microbe homeostasis.

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Bae, Yun Soo; Choi, Myoung Kwon; Lee, Won-Jae

2010-07-01

Mucosal epithelia are in direct contact with microbes, which range from beneficial symbionts to pathogens. Accordingly, hosts must have a conflicting strategy to combat pathogens efficiently while tolerating symbionts. Recent progress has revealed that dual oxidase (DUOX) plays a key role in mucosal immunity in organisms that range from flies to humans. Information from the genetic model of Drosophila has advanced our understanding of the regulatory mechanism of DUOX and its role in mucosal immunity. Further investigations of DUOX regulation in response to symbiotic or non-symbiotic bacteria and the in vivo consequences in host physiology will give a novel insight into the microbe-controlling system of the mucosa. Copyright 2010 Elsevier Ltd. All rights reserved.

Host Cell Responses to Persistent Mycoplasmas - Different Stages in Infection of HeLa Cells with Mycoplasma hominis

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Hopfe, Miriam; Deenen, René; Degrandi, Daniel; Köhrer, Karl; Henrich, Birgit

2013-01-01

Mycoplasma hominis is a facultative human pathogen primarily associated with bacterial vaginosis and pelvic inflammatory disease, but it is also able to spread to other sites, leading to arthritis or, in neonates, meningitis. With a minimal set of 537 annotated genes, M. hominis is the second smallest self-replicating mycoplasma and thus an ideal model organism for studying the effects of an infectious agent on its host more closely. M. hominis adherence, colonisation and invasion of HeLa cells were characterised in a time-course study using scanning electron microscopy, confocal microscopy and microarray-based analysis of the HeLa cell transcriptome. At 4 h post infection, cytoadherence of M. hominis to the HeLa cell surface was accompanied by differential regulation of 723 host genes (>2 fold change in expression). Genes associated with immune responses and signal transduction pathways were mainly affected and components involved in cell-cycle regulation, growth and death were highly upregulated. At 48 h post infection, when mycoplasma invasion started, 1588 host genes were differentially expressed and expression of genes for lysosome-specific proteins associated with bacterial lysis was detected. In a chronically infected HeLa cell line (2 weeks), the proportion of intracellular mycoplasmas reached a maximum of 10% and M. hominis-filled protrusions of the host cell membrane were seen by confocal microscopy, suggesting exocytotic dissemination. Of the 1972 regulated host genes, components of the ECM-receptor interaction pathway and phagosome-related integrins were markedly increased. The immune response was quite different to that at the beginning of infection, with a prominent induction of IL1B gene expression, affecting pathways of MAPK signalling, and genes connected with cytokine-cytokine interactions and apoptosis. These data show for the first time the complex, time-dependent reaction of the host directed at mycoplasmal clearance and the counter measures of

[Validation of the modified algorithm for predicting host susceptibility to viruses taking into account susceptibility parameters of primary target cell cultures and natural immunity factors].

Science.gov (United States)

Zhukov, V A; Shishkina, L N; Safatov, A S; Sergeev, A A; P'iankov, O V; Petrishchenko, V A; Zaĭtsev, B N; Toporkov, V S; Sergeev, A N; Nesvizhskiĭ, Iu V; Vorob'ev, A A

2010-01-01

The paper presents results of testing a modified algorithm for predicting virus ID50 values in a host of interest by extrapolation from a model host taking into account immune neutralizing factors and thermal inactivation of the virus. The method was tested for A/Aichi/2/68 influenza virus in SPF Wistar rats, SPF CD-1 mice and conventional ICR mice. Each species was used as a host of interest while the other two served as model hosts. Primary lung and trachea cells and secretory factors of the rats' airway epithelium were used to measure parameters needed for the purpose of prediction. Predicted ID50 values were not significantly different (p = 0.05) from those experimentally measured in vivo. The study was supported by ISTC/DARPA Agreement 450p.

Bifidobacterium breve UCC2003 surface exopolysaccharide production is a beneficial trait mediating commensal-host interaction through immune modulation and pathogen protection.

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Fanning, Saranna; Hall, Lindsay J; van Sinderen, Douwe

2012-01-01

Bifidobacteria constitute a substantial proportion of the human gut microbiota. There are currently many bifidobacterial strains with claimed probiotic attributes. The mechanism through which these strains reside within their host and exert benefits to the host is far from fully understood. We have shown in the case of Bifidobacterium breve UCC2003 that a cell surface exopolysaccharide (EPS) plays a role in in vivo persistence. Biosynthesis of two possible EPSs is controlled by a bidirectional gene cluster which guides alternate EPS synthesis by means of a reorienting promoter. The presence of EPS impacts on host immune response: the wild type, EPS-positive B. breve UCC2003 efficiently evades the adaptive B-cell host response, while its isogenic, EPS-deficient equivalent elicits a strong adaptive immune response. Functionally, EPS positive strains were more resilient to presence of acid and bile and were responsible for reduced colonization levels of Citrobacter rodentium, a gut pathogen. In conclusion, we have found that EPS is important in host interactions and pathogen protection, the latter indicative of a probiotic ability for the EPS of B. breve UCC2003.

T cell immunity

OpenAIRE

Emel Bülbül Başkan

2013-01-01

Since birth, our immune system is constantly bombarded with self-antigens and foreign pathogens. To stay healthy, complex immune strategies have evolved in our immune system to maintain self-tolerance and to defend against foreign pathogens. Effector T cells are the key players in steering the immune responses to execute immune functions. While effector T cells were initially identified to be immune promoting, recent studies unraveled negative regulatory functions of effector T cells...

Tumour-cell killing by X-rays and immunity quantitated in a mouse model system

International Nuclear Information System (INIS)

Porteous, D.D.; Porteous, K.M.; Hughes, M.J.

1979-01-01

As part of an investigation of the interaction of X-rays and immune cytotoxicity in tumour control, an experimental mouse model system has been used in which quantitative anti-tumour immunity was raised in prospective recipients of tumour-cell suspensions exposed to varying doses of X-rays in vitro before injection. Findings reported here indicate that, whilst X-rays kill a proportion of cells, induced immunity deals with a fixed number dependent upon the immune status of the host, and that X-rays and anti-tumour immunity do not act synergistically in tumour-cell killing. The tumour used was the ascites sarcoma BP8. (author)

IRAK-M regulation and function in host defense and immune homeostasis

Directory of Open Access Journals (Sweden)

Leah L.N. Hubbard

2010-06-01

Full Text Available Antigen presenting cells (APCs of the innate immune system sense a wide range of pathogens via pattern recognition receptors (PRRs. Engagement of certain PRRs can induce production of pro-inflammatory mediators that facilitate effective clearance of pathogen. Toll-like receptors (TLRs are a well described group of PRRs that belong to the TLR/Interleukin-1 receptor (IL-1R superfamily. However, TLR/IL-1R induction of pro-inflammatory mediators must be regulated to prevent excessive inflammation and tissue damage. One molecule of recent interest that is known to inhibit TLR/IL-1R signaling is interleukin-1 receptor associated kinase (IRAK-M, also known as IRAK-3. IRAK-M is expressed in a number of immune and epithelial cells types, and through its inhibition of pro-inflammatory cytokine production, IRAK-M can regulate immune homeostasis and tolerance in a number of infectious and non-infectious diseases. Furthermore, use of IRAK-M deficient animals has increased our understanding of the importance of IRAK-M in regulating immune responsiveness to a variety of pathogens. Although IRAK-M expression is typically induced through TLR signaling, IRAK-M can also be expressed in response to various endogenous and exogenous soluble factors as well as cell surface and intracellular signaling molecules. This review will focus on clinical scenarios in which expression of IRAK-M is beneficial (as in early sepsis and those situations where IRAK-M expression is harmful to the host (as in cancer and following bone marrow transplant. There is strong rationale for therapeutic targeting of IRAK-M for clinical benefit. However, effective targeting will require a greater understanding of the transcriptional regulation of this gene.

Membrane rafts: a potential gateway for bacterial entry into host cells.

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Hartlova, Anetta; Cerveny, Lukas; Hubalek, Martin; Krocova, Zuzana; Stulik, Jiri

2010-04-01

Pathogenic bacteria have developed various mechanisms to evade host immune defense systems. Invasion of pathogenic bacteria requires interaction of the pathogen with host receptors, followed by activation of signal transduction pathways and rearrangement of the cytoskeleton to facilitate bacterial entry. Numerous bacteria exploit specialized plasma membrane microdomains, commonly called membrane rafts, which are rich in cholesterol, sphingolipids and a special set of signaling molecules which allow entry to host cells and establishment of a protected niche within the host. This review focuses on the current understanding of the raft hypothesis and the means by which pathogenic bacteria subvert membrane microdomains to promote infection.

A benign helminth alters the host immune system and the gut microbiota in a rat model system.

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Laura Wegener Parfrey

Full Text Available Helminths and bacteria are major players in the mammalian gut ecosystem and each influences the host immune system and health. Declines in helminth prevalence and bacterial diversity appear to play a role in the dramatic rise of immune mediated inflammatory diseases (IMIDs in western populations. Helminths are potent modulators of immune system and their reintroduction is a promising therapeutic avenue for IMIDs. However, the introduction of helminths represents a disturbance for the host and it is important to understand the impact of helminth reintroduction on the host, including the immune system and gut microbiome. We tested the impact of a benign tapeworm, Hymenolepis diminuta, in a rat model system. We find that H. diminuta infection results in increased interleukin 10 gene expression in the beginning of the prepatent period, consistent with induction of a type 2 immune response. We also find induction of humoral immunity during the patent period, shown here by increased IgA in feces. Further, we see an immuno-modulatory effect in the small intestine and spleen in patent period, as measured by reductions in tissue immune cells. We observed shifts in microbiota community composition during the patent period (beta-diversity in response to H. diminuta infection. However, these compositional changes appear to be minor; they occur within families and genera common to both treatment groups. There was no change in alpha diversity. Hymenolepis diminuta is a promising model for helminth therapy because it establishes long-term, stable colonization in rats and modulates the immune system without causing bacterial dysbiosis. These results suggest that the goal of engineering a therapeutic helminth that can safely manipulate the mammalian immune system without disrupting the rest of the gut ecosystem is in reach.

A benign helminth alters the host immune system and the gut microbiota in a rat model system.

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Wegener Parfrey, Laura; Jirků, Milan; Šíma, Radek; Jalovecká, Marie; Sak, Bohumil; Grigore, Karina; Jirků Pomajbíková, Kateřina

2017-01-01

Helminths and bacteria are major players in the mammalian gut ecosystem and each influences the host immune system and health. Declines in helminth prevalence and bacterial diversity appear to play a role in the dramatic rise of immune mediated inflammatory diseases (IMIDs) in western populations. Helminths are potent modulators of immune system and their reintroduction is a promising therapeutic avenue for IMIDs. However, the introduction of helminths represents a disturbance for the host and it is important to understand the impact of helminth reintroduction on the host, including the immune system and gut microbiome. We tested the impact of a benign tapeworm, Hymenolepis diminuta, in a rat model system. We find that H. diminuta infection results in increased interleukin 10 gene expression in the beginning of the prepatent period, consistent with induction of a type 2 immune response. We also find induction of humoral immunity during the patent period, shown here by increased IgA in feces. Further, we see an immuno-modulatory effect in the small intestine and spleen in patent period, as measured by reductions in tissue immune cells. We observed shifts in microbiota community composition during the patent period (beta-diversity) in response to H. diminuta infection. However, these compositional changes appear to be minor; they occur within families and genera common to both treatment groups. There was no change in alpha diversity. Hymenolepis diminuta is a promising model for helminth therapy because it establishes long-term, stable colonization in rats and modulates the immune system without causing bacterial dysbiosis. These results suggest that the goal of engineering a therapeutic helminth that can safely manipulate the mammalian immune system without disrupting the rest of the gut ecosystem is in reach.

Gut symbiotic microbes imprint intestinal immune cells with the innate receptor SLAMF4 which contributes to gut immune protection against enteric pathogens.

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Cabinian, Allison; Sinsimer, Daniel; Tang, May; Jang, Youngsoon; Choi, Bongkum; Laouar, Yasmina; Laouar, Amale

2018-05-01

Interactions between host immune cells and gut microbiota are crucial for the integrity and function of the intestine. How these interactions regulate immune cell responses in the intestine remains a major gap in the field. We have identified the signalling lymphocyte activation molecule family member 4 (SLAMF4) as an immunomodulator of the intestinal immunity. The aim is to determine how SLAMF4 is acquired in the gut and what its contribution to intestinal immunity is. Expression of SLAMF4 was assessed in mice and humans. The mechanism of induction was studied using GFP tg bone marrow chimaera mice, lymphotoxin α and TNLG8A-deficient mice, as well as gnotobiotic mice. Role in immune protection was revealed using oral infection with Listeria monocytogenes and Cytobacter rodentium . SLAMF4 is a selective marker of intestinal immune cells of mice and humans. SLAMF4 induction occurs directly in the intestinal mucosa without the involvement of the gut-associated lymphoid tissue. Gut bacterial products, particularly those of gut anaerobes, and gut-resident antigen-presenting cell (APC) TNLG8A are key contributors of SLAMF4 induction in the intestine. Importantly, lack of SLAMF4 expression leads the increased susceptibility of mice to infection by oral pathogens culminating in their premature death. SLAMF4 is a marker of intestinal immune cells which contributes to the protection against enteric pathogens and whose expression is dependent on the presence of the gut microbiota. This discovery provides a possible mechanism for answering the long-standing question of how the intertwining of the host and gut microbial biology regulates immune cell responses in the gut. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Trypanosome infection establishment in the tsetse fly gut is influenced by microbiome-regulated host immune barriers.

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Brian L Weiss

Full Text Available Tsetse flies (Glossina spp. vector pathogenic African trypanosomes, which cause sleeping sickness in humans and nagana in domesticated animals. Additionally, tsetse harbors 3 maternally transmitted endosymbiotic bacteria that modulate their host's physiology. Tsetse is highly resistant to infection with trypanosomes, and this phenotype depends on multiple physiological factors at the time of challenge. These factors include host age, density of maternally-derived trypanolytic effector molecules present in the gut, and symbiont status during development. In this study, we investigated the molecular mechanisms that result in tsetse's resistance to trypanosomes. We found that following parasite challenge, young susceptible tsetse present a highly attenuated immune response. In contrast, mature refractory flies express higher levels of genes associated with humoral (attacin and pgrp-lb and epithelial (inducible nitric oxide synthase and dual oxidase immunity. Additionally, we discovered that tsetse must harbor its endogenous microbiome during intrauterine larval development in order to present a parasite refractory phenotype during adulthood. Interestingly, mature aposymbiotic flies (Gmm(Apo present a strong immune response earlier in the infection process than do WT flies that harbor symbiotic bacteria throughout their entire lifecycle. However, this early response fails to confer significant resistance to trypanosomes. Gmm(Apo adults present a structurally compromised peritrophic matrix (PM, which lines the fly midgut and serves as a physical barrier that separates luminal contents from immune responsive epithelial cells. We propose that the early immune response we observe in Gmm(Apo flies following parasite challenge results from the premature exposure of gut epithelia to parasite-derived immunogens in the absence of a robust PM. Thus, tsetse's PM appears to regulate the timing of host immune induction following parasite challenge. Our results

The role of CD103+ Dendritic cells in the intestinal mucosal immune system.

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Darren Thomas Ruane

2011-07-01

Full Text Available While dendritic cells (DC are central to the induction and regulation of adaptive immunity, these cells are very heterogenous and specific subsets can be characterized based on the expression of cell surface markers and functional properties. Intestinal CD103+ DCs are the subject of particular interest due to their role in regulating mucosal immunity. Since the epithelial surfaces are constantly exposed to a high antigenic load, tight regulation of innate and adaptive intestinal immune responses is vital as intestinal inflammation can have detrimental consequences for the host. Strategically positioned within the lamina propria, CD103+ DCs play an important role in maintaining intestinal immune homeostasis. These cells are required for the induction of tolerogenic immune responses and imprinting gut homing phenotypic changes on antigen-specific T cells. Recent insights into their development and regulatory properties have revealed additional immunoregulatory roles and further highlighted their importance for intestinal immunity. In this review we discuss the nature of the intestinal CD103+ DC population and the emerging roles of these cells in the regulation of mucosal immunity.

Characterisation of cell death inducing Phytophthora capsici CRN effectors suggests diverse activities in the host nucleus

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Remco eStam

2013-10-01

Full Text Available Plant-Microbe interactions are complex associations that feature recognition of Pathogen Associated Molecular Patterns by the plant immune system and dampening of subsequent responses by pathogen encoded secreted effectors. With large effector repertoires now identified in a range of sequenced microbial genomes, much attention centres on understanding their roles in immunity or disease. These studies not only allow identification of pathogen virulence factors and strategies, they also provide an important molecular toolset suited for studying immunity in plants. The Phytophthora intracellular effector repertoire encodes a large class of proteins that translocate into host cells and exclusively target the host nucleus. Recent functional studies have implicated the CRN protein family as an important class of diverse effectors that target distinct subnuclear compartments and modify host cell signalling. Here, we characterised three necrosis inducing CRNs and show that there are differences in the levels of cell death. We show that only expression of CRN20_624 has an additive effect on PAMP induced cell death but not AVR3a induced ETI. Given their distinctive phenotypes, we assessed localisation of each CRN with a set of nuclear markers and found clear differences in CRN subnuclear distribution patterns. These assays also revealed that expression of CRN83_152 leads to a distinct change in nuclear chromatin organisation, suggesting a distinct series of events that leads to cell death upon over-expression. Taken together, our results suggest diverse functions carried by CRN C-termini, which can be exploited to identify novel processes that take place in the host nucleus and are required for immunity or susceptibility.

Human and Animal Isolates of Yersinia enterocolitica Show Significant Serotype-Specific Colonization and Host-Specific Immune Defense Properties

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Schaake, Julia; Kronshage, Malte; Uliczka, Frank; Rohde, Manfred; Knuuti, Tobias; Strauch, Eckhard; Fruth, Angelika; Wos-Oxley, Melissa

2013-01-01

Yersinia enterocolitica is a human pathogen that is ubiquitous in livestock, especially pigs. The bacteria are able to colonize the intestinal tract of a variety of mammalian hosts, but the severity of induced gut-associated diseases (yersiniosis) differs significantly between hosts. To gain more information about the individual virulence determinants that contribute to colonization and induction of immune responses in different hosts, we analyzed and compared the interactions of different human- and animal-derived isolates of serotypes O:3, O:5,27, O:8, and O:9 with murine, porcine, and human intestinal cells and macrophages. The examined strains exhibited significant serotype-specific cell binding and entry characteristics, but adhesion and uptake into different host cells were not host specific and were independent of the source of the isolate. In contrast, survival and replication within macrophages and the induced proinflammatory response differed between murine, porcine, and human macrophages, suggesting a host-specific immune response. In fact, similar levels of the proinflammatory cytokine macrophage inflammatory protein 2 (MIP-2) were secreted by murine bone marrow-derived macrophages with all tested isolates, but the equivalent interleukin-8 (IL-8) response of porcine bone marrow-derived macrophages was strongly serotype specific and considerably lower in O:3 than in O:8 strains. In addition, all tested Y. enterocolitica strains caused a considerably higher level of secretion of the anti-inflammatory cytokine IL-10 by porcine than by murine macrophages. This could contribute to limiting the severity of the infection (in particular of serotype O:3 strains) in pigs, which are the primary reservoir of Y. enterocolitica strains pathogenic to humans. PMID:23959720

Cell-mediated immunity to histocompatibility antigens : controlling factors, with emphasis on Graft-versus-host reactions in mice

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H. Bril (Herman)

1984-01-01

textabstractGraft-versus-Host (GvH) disease is characterized by weight loss, diarrhea, skin lesions, hypofunction of the immune system with concomitant infections, etc. This syndrome is potentially lethal. GvH reactions, which underly this disease, may occur when immunocompetent T lymphocytes are

Alemtuzumab-induced elimination of HIV-1-infected immune cells.

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Ruxrungtham, Kiat; Sirivichayakul, Sunee; Buranapraditkun, Supranee; Krause, Werner

2016-01-01

Currently, there is no drug known that is able to eradicate either HIV or HIV-infected host cells. The effectiveness of all available treatments is based on the prevention of viral replication. We investigated whether the monoclonal, CD52 receptor-targeting antibody, alemtuzumab, which is currently approved for the treatment of multiple sclerosis, is able to eliminate HIV-infected immune cells. In blood samples from healthy donors and from HIV-1-infected subjects who were either treatment-naïve or resistant to HAART, we studied whether the CD52 expression on T cells and their subsets (CD3, CD4, CD8), B cells (CD19), dendritic cells (CD123) and monocytes (CD11c) is retained in HIV-1 infection and whether alemtuzumab is able to eradicate infected cells, using four-colour flow cytometry. We found that CD52 expression on immune cells is retained in HIV-1 infection regardless of CD4 cell count, viral load and treatment status, and is amenable to alemtuzumab-induced depletion. For the first time it could be shown in vitro that HIV-1-infected immune cells can be eliminated by using the monoclonal antibody alemtuzumab.

Immune system handling time may alter the outcome of competition between pathogens and the immune system.

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Greenspoon, Philip B; Banton, Sydney; Mideo, Nicole

2018-06-14

Predators may be limited in their ability to kill prey (i.e., have type II or III functional responses), an insight that has had far-reaching consequences in the ecological literature. With few exceptions, however, this possibility has not been extended to the behaviour of immune cells, which kill pathogens much as predators kill their prey. Rather, models of the within-host environment have tended to tacitly assume that immune cells have an unlimited ability to target and kill pathogens (i.e., a type I functional response). Here we explore the effects of changing this assumption on infection outcomes (i.e., pathogen loads). We incorporate immune cell handling time into an ecological model of the within-host environment that considers both the predatory nature of the pathogen-immune cell interaction as well as competition between immune cells and pathogens for host resources. Unless pathogens can preempt immune cells for host resources, adding an immune cell handling time increases equilibrium pathogen load. We find that the shape of the relationship between energy intake and pathogen load can change: with a type I functional response, pathogen load is maximised at intermediate inputs, while for a type II or III functional response, pathogen load is solely increasing. With a type II functional response, pathogen load can fluctuate rather than settling to an equilibrium, a phenomenon unobserved with type I or III functional responses. Our work adds to a growing literature highlighting the role of resource availability in host-parasite interactions. Implications of our results for adaptive anorexia are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of worm development and host immune responses in natural hosts of schistosoma japonicum, yellow cattle and water buffalo

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Yang Jianmei

2012-03-01

Full Text Available Abstract Background Yellow cattle and water buffalo are two of the most important natural hosts for Schistosoma japonicum in China. Previous observation has revealed that yellow cattle are more suited to the development of S. japonicum than water buffalo. Understanding more about the molecular mechanisms involved in worm development, as well as the pathological and immunological differences between yellow cattle and water buffalo post infection with S japonicum will provide useful information for the vaccine design and its delivery procedure. Results The worm length (p p p + T cells was higher in yellow cattle, while the percentage of CD8+ T cells was higher in water buffalo from pre-infection to 7 w post infection. The CD4/CD8 ratios were decreased in both species after challenge with schistosomes. Comparing with water buffalo, the IFN-γ level was higher and decreased significantly, while the IL-4 level was lower and increased gradually in yellow cattle from pre-infection to 7 w post infection. Conclusions In this study, we confirmed that yellow cattle were more suited to the development of S. japonicum than water buffalo, and more serious pathological damage was observed in infected yellow cattle. Immunological analysis suggested that CD4+ T cells might be an integral component of the immune response and might associate with worm development in yellow cattle. A shift from Th1 to Th2 type polarized immunity was only shown clearly in schistosome-infected yellow cattle, but no shift in water buffalo. The results provide valuable information for increased understanding of host-schistosome interactions, and for control of schistosomiasis.

Pteromalus puparum venom impairs host cellular immune responses by decreasing expression of its scavenger receptor gene

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Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Although there is a rich literature on these systems, parasitoid immune-disabling mechanisms have not been fully elucidated. Here we ...

Cell intrinsic immunity spreads to bystander cells via the intercellular transfer of cGAMP.

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Ablasser, Andrea; Schmid-Burgk, Jonathan L; Hemmerling, Inga; Horvath, Gabor L; Schmidt, Tobias; Latz, Eicke; Hornung, Veit

2013-11-28

The innate immune defence of multicellular organisms against microbial pathogens requires cellular collaboration. Information exchange allowing immune cells to collaborate is generally attributed to soluble protein factors secreted by pathogen-sensing cells. Cytokines, such as type I interferons (IFNs), serve to alert non-infected cells to the possibility of pathogen challenge. Moreover, in conjunction with chemokines they can instruct specialized immune cells to contain and eradicate microbial infection. Several receptors and signalling pathways exist that couple pathogen sensing to the induction of cytokines, whereas cytosolic recognition of nucleic acids seems to be exquisitely important for the activation of type I IFNs, master regulators of antiviral immunity. Cytosolic DNA is sensed by the receptor cyclic GMP-AMP (cGAMP) synthase (cGAS), which catalyses the synthesis of the second messenger cGAMP(2'-5'). This molecule in turn activates the endoplasmic reticulum (ER)-resident receptor STING, thereby inducing an antiviral state and the secretion of type I IFNs. Here we find in murine and human cells that cGAS-synthesized cGAMP(2'-5') is transferred from producing cells to neighbouring cells through gap junctions, where it promotes STING activation and thus antiviral immunity independently of type I IFN signalling. In line with the limited cargo specificity of connexins, the proteins that assemble gap junction channels, most connexins tested were able to confer this bystander immunity, thus indicating a broad physiological relevance of this local immune collaboration. Collectively, these observations identify cGAS-triggered cGAMP(2'-5') transfer as a novel host strategy that serves to rapidly convey antiviral immunity in a transcription-independent, horizontal manner.

Exploiting immune cell metabolic machinery for functional HIV cure and the prevention of inflammaging [version 1; referees: 4 approved

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Clovis S. Palmer; Riya Palchaudhuri; Hassan Albargy; Mohamed Abdel-Mohsen; Suzanne M. Crowe

2018-01-01

An emerging paradigm in immunology suggests that metabolic reprogramming and immune cell activation and functions are intricately linked. Viral infections, such as HIV infection, as well as cancer force immune cells to undergo major metabolic challenges. Cells must divert energy resources in order to mount an effective immune response. However, the fact that immune cells adopt specific metabolic programs to provide host defense against intracellular pathogens and how this metabolic shift impa...

Viral Transmission Dynamics at Single-Cell Resolution Reveal Transiently Immune Subpopulations Caused by a Carrier State Association.

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William Cenens

2015-12-01

Full Text Available Monitoring the complex transmission dynamics of a bacterial virus (temperate phage P22 throughout a population of its host (Salmonella Typhimurium at single cell resolution revealed the unexpected existence of a transiently immune subpopulation of host cells that emerged from peculiarities preceding the process of lysogenization. More specifically, an infection event ultimately leading to a lysogen first yielded a phage carrier cell harboring a polarly tethered P22 episome. Upon subsequent division, the daughter cell inheriting this episome became lysogenized by an integration event yielding a prophage, while the other daughter cell became P22-free. However, since the phage carrier cell was shown to overproduce immunity factors that are cytoplasmically inherited by the P22-free daughter cell and further passed down to its siblings, a transiently resistant subpopulation was generated that upon dilution of these immunity factors again became susceptible to P22 infection. The iterative emergence and infection of transiently resistant subpopulations suggests a new bet-hedging strategy by which viruses could manage to sustain both vertical and horizontal transmission routes throughout an infected population without compromising a stable co-existence with their host.

Differential Effects of Environmental and Genetic Factors on T and B Cell Immune Traits

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Aguirre-Gamboa, Raul; Joosten, Irma; Urbano, Paulo C. M.; van der Molen, Renate G.; van Rijssen, Esther; van Cranenbroek, Bram; Oosting, Marije; Smeekens, Sanne; Jaeger, Martin; Zorro, Maria; Withoff, Sebo; van Herwaarden, Antonius E.; Sweep, Fred C. G. J.; Netea, Romana T.; Swertz, Morris A.; Franke, Lude; Xavier, Ramnik J.; Joosten, Leo A. B.; Netea, Mihai G.; Wijmenga, Cisca; Kumar, Vinod; Li, Yang; Koenen, Hans J. P. M.

2016-01-01

Effective immunity requires a complex network of cellular and humoral components that interact with each other and are influenced by different environmental and host factors. We used a systems biology approach to comprehensively assess the impact of environmental and genetic factors on immune cell

Establishment of Myotis myotis cell lines--model for investigation of host-pathogen interaction in a natural host for emerging viruses.

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Xiaocui He

Full Text Available Bats are found to be the natural reservoirs for many emerging viruses. In most cases, severe clinical signs caused by such virus infections are normally not seen in bats. This indicates differences in the virus-host interactions and underlines the necessity to develop natural host related models to study these phenomena. Due to the strict protection of European bat species, immortalized cell lines are the only alternative to investigate the innate anti-virus immune mechanisms. Here, we report about the establishment and functional characterization of Myotis myotis derived cell lines from different tissues: brain (MmBr, tonsil (MmTo, peritoneal cavity (MmPca, nasal epithelium (MmNep and nervus olfactorius (MmNol after immortalization by SV 40 large T antigen. The usefulness of these cell lines to study antiviral responses has been confirmed by analysis of their susceptibility to lyssavirus infection and the mRNA patterns of immune-relevant genes after poly I:C stimulation. Performed experiments indicated varying susceptibility to lyssavirus infection with MmBr being considerably less susceptible than the other cell lines. Further investigation demonstrated a strong activation of interferon mediated antiviral response in MmBr contributing to its resistance. The pattern recognition receptors: RIG-I and MDA5 were highly up-regulated during rabies virus infection in MmBr, suggesting their involvement in promotion of antiviral responses. The presence of CD14 and CD68 in MmBr suggested MmBr cells are microglia-like cells which play a key role in host defense against infections in the central nervous system (CNS. Thus the expression pattern of MmBr combined with the observed limitation of lyssavirus replication underpin a protective mechanism of the CNS controlling the lyssavirus infection. Overall, the established cell lines are important tools to analyze antiviral innate immunity in M. myotis against neurotropic virus infections and present a valuable

Establishment of Myotis myotis cell lines--model for investigation of host-pathogen interaction in a natural host for emerging viruses.

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He, Xiaocui; Korytář, Tomáš; Zhu, Yaqing; Pikula, Jiří; Bandouchova, Hana; Zukal, Jan; Köllner, Bernd

2014-01-01

Bats are found to be the natural reservoirs for many emerging viruses. In most cases, severe clinical signs caused by such virus infections are normally not seen in bats. This indicates differences in the virus-host interactions and underlines the necessity to develop natural host related models to study these phenomena. Due to the strict protection of European bat species, immortalized cell lines are the only alternative to investigate the innate anti-virus immune mechanisms. Here, we report about the establishment and functional characterization of Myotis myotis derived cell lines from different tissues: brain (MmBr), tonsil (MmTo), peritoneal cavity (MmPca), nasal epithelium (MmNep) and nervus olfactorius (MmNol) after immortalization by SV 40 large T antigen. The usefulness of these cell lines to study antiviral responses has been confirmed by analysis of their susceptibility to lyssavirus infection and the mRNA patterns of immune-relevant genes after poly I:C stimulation. Performed experiments indicated varying susceptibility to lyssavirus infection with MmBr being considerably less susceptible than the other cell lines. Further investigation demonstrated a strong activation of interferon mediated antiviral response in MmBr contributing to its resistance. The pattern recognition receptors: RIG-I and MDA5 were highly up-regulated during rabies virus infection in MmBr, suggesting their involvement in promotion of antiviral responses. The presence of CD14 and CD68 in MmBr suggested MmBr cells are microglia-like cells which play a key role in host defense against infections in the central nervous system (CNS). Thus the expression pattern of MmBr combined with the observed limitation of lyssavirus replication underpin a protective mechanism of the CNS controlling the lyssavirus infection. Overall, the established cell lines are important tools to analyze antiviral innate immunity in M. myotis against neurotropic virus infections and present a valuable tool for a

Establishment of Myotis myotis Cell Lines - Model for Investigation of Host-Pathogen Interaction in a Natural Host for Emerging Viruses

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He, Xiaocui; Korytář, Tomáš; Zhu, Yaqing; Pikula, Jiří; Bandouchova, Hana; Zukal, Jan; Köllner, Bernd

2014-01-01

Bats are found to be the natural reservoirs for many emerging viruses. In most cases, severe clinical signs caused by such virus infections are normally not seen in bats. This indicates differences in the virus-host interactions and underlines the necessity to develop natural host related models to study these phenomena. Due to the strict protection of European bat species, immortalized cell lines are the only alternative to investigate the innate anti-virus immune mechanisms. Here, we report about the establishment and functional characterization of Myotis myotis derived cell lines from different tissues: brain (MmBr), tonsil (MmTo), peritoneal cavity (MmPca), nasal epithelium (MmNep) and nervus olfactorius (MmNol) after immortalization by SV 40 large T antigen. The usefulness of these cell lines to study antiviral responses has been confirmed by analysis of their susceptibility to lyssavirus infection and the mRNA patterns of immune-relevant genes after poly I:C stimulation. Performed experiments indicated varying susceptibility to lyssavirus infection with MmBr being considerably less susceptible than the other cell lines. Further investigation demonstrated a strong activation of interferon mediated antiviral response in MmBr contributing to its resistance. The pattern recognition receptors: RIG-I and MDA5 were highly up-regulated during rabies virus infection in MmBr, suggesting their involvement in promotion of antiviral responses. The presence of CD14 and CD68 in MmBr suggested MmBr cells are microglia-like cells which play a key role in host defense against infections in the central nervous system (CNS). Thus the expression pattern of MmBr combined with the observed limitation of lyssavirus replication underpin a protective mechanism of the CNS controlling the lyssavirus infection. Overall, the established cell lines are important tools to analyze antiviral innate immunity in M. myotis against neurotropic virus infections and present a valuable tool for a

Coxiella burnetii Nine Mile II proteins modulate gene expression of monocytic host cells during infection

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Shaw Edward I

2010-09-01

Full Text Available Abstract Background Coxiella burnetii is an intracellular bacterial pathogen that causes acute and chronic disease in humans. Bacterial replication occurs within enlarged parasitophorous vacuoles (PV of eukaryotic cells, the biogenesis and maintenance of which is dependent on C. burnetii protein synthesis. These observations suggest that C. burnetii actively subverts host cell processes, however little is known about the cellular biology mechanisms manipulated by the pathogen during infection. Here, we examined host cell gene expression changes specifically induced by C. burnetii proteins during infection. Results We have identified 36 host cell genes that are specifically regulated when de novo C. burnetii protein synthesis occurs during infection using comparative microarray analysis. Two parallel sets of infected and uninfected THP-1 cells were grown for 48 h followed by the addition of chloramphenicol (CAM to 10 μg/ml in one set. Total RNA was harvested at 72 hpi from all conditions, and microarrays performed using Phalanx Human OneArray™ slides. A total of 784 (mock treated and 901 (CAM treated THP-1 genes were up or down regulated ≥2 fold in the C. burnetii infected vs. uninfected cell sets, respectively. Comparisons between the complementary data sets (using >0 fold, eliminated the common gene expression changes. A stringent comparison (≥2 fold between the separate microarrays revealed 36 host cell genes modulated by C. burnetii protein synthesis. Ontological analysis of these genes identified the innate immune response, cell death and proliferation, vesicle trafficking and development, lipid homeostasis, and cytoskeletal organization as predominant cellular functions modulated by C. burnetii protein synthesis. Conclusions Collectively, these data indicate that C. burnetii proteins actively regulate the expression of specific host cell genes and pathways. This is in addition to host cell genes that respond to the presence of the

Zinc and immunity: An essential interrelation.

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Maares, Maria; Haase, Hajo

2016-12-01

The significance of the essential trace element zinc for immune function has been known for several decades. Zinc deficiency affects immune cells, resulting in altered host defense, increased risk of inflammation, and even death. The micronutrient zinc is important for maintenance and development of immune cells of both the innate and adaptive immune system. A disrupted zinc homeostasis affects these cells, leading to impaired formation, activation, and maturation of lymphocytes, disturbed intercellular communication via cytokines, and weakened innate host defense via phagocytosis and oxidative burst. This review outlines the connection between zinc and immunity by giving a survey on the major roles of zinc in immune cell function, and their potential consequences in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

Viral immune evasion: a masterpiece of evolution

NARCIS (Netherlands)

Vossen, Mireille T. M.; Westerhout, Ellen M.; Söderberg-Nauclér, Cécilia; Wiertz, Emmanuel J. H. J.

2002-01-01

Coexistence of viruses and their hosts imposes an evolutionary pressure on both the virus and the host immune system. On the one hand, the host has developed an immune system able to attack viruses and virally infected cells, whereas on the other hand, viruses have developed an array of immune

Host ploidy, parasitism and immune defence in a coevolutionary snail-trematode system.

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Osnas, E E; Lively, C M

2006-01-01

We studied the role of host ploidy and parasite exposure on immune defence allocation in a snail-trematode system (Potamopyrgus antipodarum-Microphallus sp.). In the field, haemocyte (the defence cell) concentration was lowest in deep-water habitats where infection is relatively low and highest in shallow-water habitats where infection is common. Because the frequency of asexual triploid snails is positively correlated with depth, we also experimentally studied the role of ploidy by exposing both diploid sexual and triploid asexual snails to Microphallus eggs. We found that triploid snails had lower haemocyte concentrations than did diploids in both parasite-addition and parasite-free treatments. We also found that both triploids and diploids increased their numbers of large granular haemocytes at similar rates after parasite exposure. Because triploid P. antipodarum have been shown to be more resistant to allopatric parasites than diploids, the current results suggest that the increased resistance of triploids is because of intrinsic genetic properties rather than to greater allocation to defence cells. This finding is consistent with recent theory on the advantages of increased ploidy for hosts combating coevolving parasites.

Group 2 Innate Lymphoid Cells in Pulmonary Immunity and Tissue Homeostasis

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Barbara C. Mindt

2018-04-01

Full Text Available Group 2 innate lymphoid cells (ILC2 represent an evolutionary rather old but only recently identified member of the family of innate lymphoid cells and have received much attention since their detailed description in 2010. They can orchestrate innate as well as adaptive immune responses as they interact with and influence several immune and non-immune cell populations. Moreover, ILC2 are able to rapidly secrete large amounts of type 2 cytokines that can contribute to protective but also detrimental host immune responses depending on timing, location, and physiological context. Interestingly, ILC2, despite their scarcity, are the dominant innate lymphoid cell population in the lung, indicating a key role as first responders and amplifiers upon immune challenge at this site. In addition, the recently described tissue residency of ILC2 further underlines the importance of their respective microenvironment. In this review, we provide an overview of lung physiology including a description of the most prominent pulmonary resident cells together with a review of known and potential ILC2 interactions within this unique environment. We will further outline recent observations regarding pulmonary ILC2 during immune challenge including respiratory infections and discuss different models and approaches to study ILC2 biology in the lung.

Group 2 Innate Lymphoid Cells in Pulmonary Immunity and Tissue Homeostasis.

Science.gov (United States)

Mindt, Barbara C; Fritz, Jörg H; Duerr, Claudia U

2018-01-01

Group 2 innate lymphoid cells (ILC2) represent an evolutionary rather old but only recently identified member of the family of innate lymphoid cells and have received much attention since their detailed description in 2010. They can orchestrate innate as well as adaptive immune responses as they interact with and influence several immune and non-immune cell populations. Moreover, ILC2 are able to rapidly secrete large amounts of type 2 cytokines that can contribute to protective but also detrimental host immune responses depending on timing, location, and physiological context. Interestingly, ILC2, despite their scarcity, are the dominant innate lymphoid cell population in the lung, indicating a key role as first responders and amplifiers upon immune challenge at this site. In addition, the recently described tissue residency of ILC2 further underlines the importance of their respective microenvironment. In this review, we provide an overview of lung physiology including a description of the most prominent pulmonary resident cells together with a review of known and potential ILC2 interactions within this unique environment. We will further outline recent observations regarding pulmonary ILC2 during immune challenge including respiratory infections and discuss different models and approaches to study ILC2 biology in the lung.

Improved Insulin Sensitivity despite Increased Visceral Adiposity in Mice Deficient for the Immune Cell Transcription Factor T-bet

Science.gov (United States)

Stolarczyk, Emilie; Vong, Chi Teng; Perucha, Esperanza; Jackson, Ian; Cawthorne, Michael A.; Wargent, Edward T.; Powell, Nick; Canavan, James B.; Lord, Graham M.; Howard, Jane K.

2013-01-01

Summary Low-grade inflammation in fat is associated with insulin resistance, although the mechanisms are unclear. We report that mice deficient in the immune cell transcription factor T-bet have lower energy expenditure and increased visceral fat compared with wild-type mice, yet paradoxically are more insulin sensitive. This striking phenotype, present in young T-bet−/− mice, persisted with high-fat diet and increasing host age and was associated with altered immune cell numbers and cytokine secretion specifically in visceral adipose tissue. However, the favorable metabolic phenotype observed in T-bet-deficient hosts was lost in T-bet−/− mice also lacking adaptive immunity (T-bet−/−xRag2−/−), demonstrating that T-bet expression in the adaptive rather than the innate immune system impacts host glucose homeostasis. Indeed, adoptive transfer of T-bet-deficient, but not wild-type, CD4+ T cells to Rag2−/− mice improved insulin sensitivity. Our results reveal a role for T-bet in metabolic physiology and obesity-associated insulin resistance. PMID:23562076

Host immune cellular reactions in corneal neovascularization

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Nizar S. Abdelfattah

2016-04-01

Full Text Available Corneal neovascularization (CNV is a global important cause of visual impairment. The immune mechanisms leading to corneal heme- and lymphangiogenesis have been extensively studied over the past years as more attempts were made to develop better prophylactic and therapeutic measures. This article aims to discuss immune cells of particular relevance to CNV, with a focus on macrophages, Th17 cells, dendritic cells and the underlying immunology of common pathologies involving neovascularization of the cornea. Hopefully, a thorough understanding of these topics would propel the efforts to halt the detrimental effects of CNV.

Demodex canis targets TLRs to evade host immunity and induce canine demodicosis.

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Kumari, P; Nigam, R; Choudhury, S; Singh, S K; Yadav, B; Kumar, D; Garg, S K

2018-03-01

Widespread incidence of Demodex mites throughout the mammalian class and occasional serious and fatal outcomes in dogs warrant an insight into the host-parasite interface especially. Therefore, this study was aimed to unravel the interplay between innate immune response and canine demodicosis. The dogs diagnosed to have natural clinical demodicosis were allocated into two groups; dogs with localized demodicosis (LD) and with generalized demodicosis (GD). The expression of toll-like receptors (TLRs) 2, 4 and 6 genes in peripheral blood mononuclear cells of these dogs was quantified by real-time PCR. Significantly increased TLR2 gene expression, while significantly diminished TLR4 and TLR6 gene expressions were observed in demodicosed dogs (LD and GD) as compared with the healthy ones. Even the expression of TLR2 gene was found to differ significantly between the dogs with LD and GD. Therefore, it can be inferred that clinical demodicosis in dogs is coupled with an up-regulation of TLR2 and down-regulation of TLR4 and TLR6 gene expressions. Overexpression of TLR2 gene might be responsible for Demodex-induced clinical manifestations, while TLR4 and TLR6 gene down-regulations could be the paramount strategy of Demodex mites to elude the host-immune interface. © 2017 John Wiley & Sons Ltd.

Beneficial and Harmful Interactions of Antibiotics with Microbial Pathogens and the Host Innate Immune System

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Ronald Anderson

2010-05-01

Full Text Available In general antibiotics interact cooperatively with host defences, weakening and decreasing the virulence of microbial pathogens, thereby increasing vulnerability to phagocytosis and eradication by the intrinsic antimicrobial systems of the host. Antibiotics, however, also interact with host defences by several other mechanisms, some harmful, others beneficial. Harmful activities include exacerbation of potentially damaging inflammatory responses, a property of cell-wall targeted agents, which promotes the release of pro-inflammatory microbial cytotoxins and cell-wall components. On the other hand, inhibitors of bacterial protein synthesis, especially macrolides, possess beneficial anti-inflammatory/cytoprotective activities, which result from interference with the production of microbial virulence factors/cytotoxins. In addition to these pathogen-directed, anti-inflammatory activities, some classes of antimicrobial agent possess secondary anti-inflammatory properties, unrelated to their conventional antimicrobial activities, which target cells of the innate immune system, particularly neutrophils. This is a relatively uncommon, potentially beneficial property of antibiotics, which has been described for macrolides, imidazole anti-mycotics, fluoroquinolones, and tetracyclines. Although of largely unproven significance in the clinical setting, increasing awareness of the pro-inflammatory and anti-inflammatory properties of antibiotics may contribute to a more discerning and effective use of these agents.

Location of tumor affects local and distant immune cell type and number.

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Hensel, Jonathan A; Khattar, Vinayak; Ashton, Reading; Lee, Carnellia; Siegal, Gene P; Ponnazhagan, Selvarangan

2017-03-01

Tumors comprise heterogeneous populations of cells, including immune infiltrates that polarize during growth and metastasis. Our preclinical studies on breast cancer (BCa) identified functional differences in myeloid-derived suppressor cells based on tumor microenvironment (TME), prompting variations in host immune response to tumor growth, and dissemination based on tissue type. In order to understand if such variations existed among other immune cells, and if such alteration occurs in response to tumor growth at the primary site or due to bone dissemination, we characterized immune cells, examining localized growth and in the tibia. In addition, immune cells from the spleen were examined from animals of both tumor locations by flow cytometry. The study demonstrates that location of tumor, and not simply the tumor itself, has a definitive role in regulating immune effectors. Among all immune cells characterized, macrophages were decreased and myeloid dendritic cell were increased in both tumor locations. This difference was more evident in subcutaneous tumors. Additionally, spleens from mice with subcutaneous tumors contained greater increases in both macrophages and myeloid dendritic cells than in mice with bone tumors. Furthermore, in subcutaneous tumors there was an increase in CD4 + and CD8 + T-cell numbers, which was also observed in their spleens. These data indicate that alterations in tumor-reactive immune cells are more pronounced at the primary site, and exert a similar change at the major secondary lymphoid organ than in the bone TME. These findings could provide translational insight into designing therapeutic strategies that account for location of metastatic foci.

Induction of cell-mediated immunity during early stages of infection with intracellular protozoa

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Gazzinelli R.T.

1998-01-01

Full Text Available Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI maintained by Th1 lymphocytes and IFN-g. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serves as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are their obligatory niche in the vertebrate host. Recent reports show that the initiation of IL-12 synthesis by macrophages during these parasitic infections is a key event in regulating CMI and disease outcome. The studies reviewed here indicate that activation/inhibition of distinct signaling pathways and certain macrophage functions by intracellular protozoa are important events in inducing/modulating the immune response of their vertebrate hosts, allowing parasite and host survival and therefore maintaining parasite life cycles.

Remodeling of the Host Cell Plasma Membrane by HIV-1 Nef and Vpu: A Strategy to Ensure Viral Fitness and Persistence.

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Sugden, Scott M; Bego, Mariana G; Pham, Tram N Q; Cohen, Éric A

2016-03-03

The plasma membrane protects the cell from its surroundings and regulates cellular communication, homing, and metabolism. Not surprisingly, the composition of this membrane is highly controlled through the vesicular trafficking of proteins to and from the cell surface. As intracellular pathogens, most viruses exploit the host plasma membrane to promote viral replication while avoiding immune detection. This is particularly true for the enveloped human immunodeficiency virus (HIV), which assembles and obtains its lipid shell directly at the plasma membrane. HIV-1 encodes two proteins, negative factor (Nef) and viral protein U (Vpu), which function primarily by altering the quantity and localization of cell surface molecules to increase virus fitness despite host antiviral immune responses. These proteins are expressed at different stages in the HIV-1 life cycle and employ a variety of mechanisms to target both unique and redundant surface proteins, including the viral receptor CD4, host restriction factors, immunoreceptors, homing molecules, tetraspanins and membrane transporters. In this review, we discuss recent progress in the study of the Nef and Vpu targeting of host membrane proteins with an emphasis on how remodeling of the cell membrane allows HIV-1 to avoid host antiviral immune responses leading to the establishment of systemic and persistent infection.

Dual RNA-seq reveals no plastic transcriptional response of the coccidian parasite Eimeria falciformis to host immune defenses.

Science.gov (United States)

Ehret, Totta; Spork, Simone; Dieterich, Christoph; Lucius, Richard; Heitlinger, Emanuel

2017-09-05

Parasites can either respond to differences in immune defenses that exist between individual hosts plastically or, alternatively, follow a genetically canalized ("hard wired") program of infection. Assuming that large-scale functional plasticity would be discernible in the parasite transcriptome we have performed a dual RNA-seq study of the lifecycle of Eimeria falciformis using infected mice with different immune status as models for coccidian infections. We compared parasite and host transcriptomes (dual transcriptome) between naïve and challenge infected mice, as well as between immune competent and immune deficient ones. Mice with different immune competence show transcriptional differences as well as differences in parasite reproduction (oocyst shedding). Broad gene categories represented by differently abundant host genes indicate enrichments for immune reaction and tissue repair functions. More specifically, TGF-beta, EGF, TNF and IL-1 and IL-6 are examples of functional annotations represented differently depending on host immune status. Much in contrast, parasite transcriptomes were neither different between Coccidia isolated from immune competent and immune deficient mice, nor between those harvested from naïve and challenge infected mice. Instead, parasite transcriptomes have distinct profiles early and late in infection, characterized largely by biosynthesis or motility associated functional gene groups, respectively. Extracellular sporozoite and oocyst stages showed distinct transcriptional profiles and sporozoite transcriptomes were found enriched for species specific genes and likely pathogenicity factors. We propose that the niche and host-specific parasite E. falciformis uses a genetically canalized program of infection. This program is likely fixed in an evolutionary process rather than employing phenotypic plasticity to interact with its host. This in turn might limit the potential of the parasite to adapt to new host species or niches, forcing

Effects of bestatin on the host immunity in patients treated for urogenital cancer

International Nuclear Information System (INIS)

Ozono, S.; Iwai, A.; Babaya, K.; Hiramatsu, T.; Yoshida, K.; Yamada, K.; Hirao, Y.; Aoyama, H.; Ohara, S.; Okajima, E.

1990-01-01

To examine effects of bestatin on the host immunity of patients with urogenital cancer, 54 patients were randomized into 2 groups: bestatin treated and controls. In each group, the patients were divided into 2 subgroups: one which received basic treatment expected to greatly affect host immunity ('invasive treatment') while the other one received other types of basic treatment ('non-invasive treatment'). Peripheral lymphocyte, OKT 4/8 ratio and purified protein derivative (PPD) skin reaction were used as immunological markers. There were significant differences in the 'invasive' treatment group between bestatin treated patients and controls concerning lymphocyte counts and PPD skin reactions and in the 'non-invasive' group concerning lymphocyte counts and OKT 4/8 ratios. These results suggest that bestatin may potentiate host immunity in patients with urogenital cancer. Further studies on larger materials are, however, needed before more definite conclusions can be drawn. (orig.)

Regulation of the Host Antiviral State by Intercellular Communications

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Sonia Assil

2015-08-01

Full Text Available Viruses usually induce a profound remodeling of host cells, including the usurpation of host machinery to support their replication and production of virions to invade new cells. Nonetheless, recognition of viruses by the host often triggers innate immune signaling, preventing viral spread and modulating the function of immune cells. It conventionally occurs through production of antiviral factors and cytokines by infected cells. Virtually all viruses have evolved mechanisms to blunt such responses. Importantly, it is becoming increasingly recognized that infected cells also transmit signals to regulate innate immunity in uninfected neighboring cells. These alternative pathways are notably mediated by vesicular secretion of various virus- and host-derived products (miRNAs, RNAs, and proteins and non-infectious viral particles. In this review, we focus on these newly-described modes of cell-to-cell communications and their impact on neighboring cell functions. The reception of these signals can have anti- and pro-viral impacts, as well as more complex effects in the host such as oncogenesis and inflammation. Therefore, these “broadcasting” functions, which might be tuned by an arms race involving selective evolution driven by either the host or the virus, constitute novel and original regulations of viral infection, either highly localized or systemic.

Gastrointestinal helminths may affect host susceptibility to anthrax through seasonal immune trade-offs.

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Cizauskas, Carrie A; Turner, Wendy C; Wagner, Bettina; Küsters, Martina; Vance, Russell E; Getz, Wayne M

2014-11-12

Most vertebrates experience coinfections, and many pathogen-pathogen interactions occur indirectly through the host immune system. These interactions are particularly strong in mixed micro-macroparasite infections because of immunomodulatory effects of helminth parasites. While these trade-offs have been examined extensively in laboratory animals, few studies have examined them in natural systems. Additionally, many wildlife pathogens fluctuate seasonally, at least partly due to seasonal host immune changes. We therefore examined seasonality of immune resource allocation, pathogen abundance and exposure, and interactions between infections and immunity in plains zebra (Equus quagga) in Etosha National Park (ENP), Namibia, a system with strongly seasonal patterns of gastrointestinal (GI) helminth infection intensity and concurrent anthrax outbreaks. Both pathogens are environmentally transmitted, and helminth seasonality is driven by environmental pressures on free living life stages. The reasons behind anthrax seasonality are currently not understood, though anthrax is less likely directly driven by environmental factors. We measured a complex, interacting set of variables and found evidence that GI helminth infection intensities, eosinophil counts, IgE and IgGb antibody titers, and possibly IL-4 cytokine signaling were increased in wetter seasons, and that ectoparasite infestations and possibly IFN-γ cytokine signaling were increased in drier seasons. Monocyte counts and anti-anthrax antibody titers were negatively associated with wet season eosinophilia, and monocytes were negatively correlated with IgGb and IgE titers. Taken together, this supports the hypothesis that ENP wet seasons are characterized by immune resource allocation toward Th-2 type responses, while Th1-type immunity may prevail in drier seasons, and that hosts may experience Th1-Th2 trade-offs. We found evidence that this Th2-type resource allocation is likely driven by GI parasite infections

Production of interferon-gamma by in vivo tumor-sensitized T cells: Association with active antitumor immunity

International Nuclear Information System (INIS)

Bursuker, I.; Pearce, M.T.

1990-01-01

The state of active immunity to Meth A fibrosarcoma in mice immunized with an admixture of Meth A cells and Propionibacterium acnes is associated with possession by the host of spleen cells capable of producing interferon-gamma (IFN-gamma) upon in vitro restimulation with irradiated tumor cells. The ability of spleen cells from immunized mice to produce IFN-gamma in response to irradiated Meth A cells decays as active antitumor immunity is replaced by a state of immunological memory. The IFN-producing cells are L3T4+Ly2+, cyclophosphamide-sensitive and radiosensitive T cells, as determined by their sensitivity to corresponding monoclonal antibodies and complement. The induction of IFN-gamma production by in vivo tumor-sensitized T cells is tumor specific, in that spleen cells from mice immunized against Meth A fibrosarcoma can produce IFN in response to irradiated Meth A cells but not in response to another syngeneic tumor M109 lung carcinoma

Tumor Necrosis Factor-α Is Required for Mast Cell-Mediated Host Immunity Against Cutaneous Staphylococcus aureus Infection.

Science.gov (United States)

Liu, Chao; Ouyang, Wei; Xia, Jingyan; Sun, Xiaoru; Zhao, Liying; Xu, Feng

2018-05-08

Mast cells (MCs) play a key role in immune process response to invading pathogens. This study assessed the involvement of MCs in controlling Staphylococcus aureus infection in a cutaneous infection model of MC-deficient (KitW-sh/W-sh) mice. KitW-sh/W-sh mice developed significantly larger skin lesions after the cutaneous S. aureus challenge, when compared to wild-type (WT) mice, while MC dysfunction reduced the inflammation response to S. aureus. The levels of tumor necrosis factor (TNF)-α in skin tissues were significantly decreased in KitW-sh/W-sh mice upon infection. Moreover, the exogenous administration of MCs or recombinant TNF-α effectively restored the immune response against S. aureus in KitW-sh/W-sh mice via the recruitment of neutrophils to the infected site. These results indicate that the effects of MC deficiency are largely attributed to the decrease in production of TNF-α in cutaneous S. aureus infection. In addition, S. aureus-induced MC activation was dependent on the c-kit receptor-activated phosphoinositide 3-kinase (PI3K)/AKT/P65-nuclear factor (NF-κB) pathway, which was confirmed by treatment with Masitinib (a c-kit receptor inhibitor), Wortmannin (a PI3K inhibitor), and pyrrolidine dithiocarbamate (a NF-κB inhibitor), respectively. The present study identifies the critical role of MCs in the host defense against S. aureus infection.

Bst1 is required for Candida albicans infecting host via facilitating cell wall anchorage of Glycosylphosphatidyl inositol anchored proteins

Science.gov (United States)

Liu, Wei; Zou, Zui; Huang, Xin; Shen, Hui; He, Li Juan; Chen, Si Min; Li, Li Ping; Yan, Lan; Zhang, Shi Qun; Zhang, Jun Dong; Xu, Zheng; Xu, Guo Tong; An, Mao Mao; Jiang, Yuan Ying

2016-01-01

Glycosylphosphatidyl inositol anchored proteins (GPI-APs) on fungal cell wall are essential for invasive infections. While the function of inositol deacylation of GPI-APs in mammalian cells has been previously characterized the impact of inositol deacylation in fungi and implications to host infection remains largely unexplored. Herein we describe our identification of BST1, an inositol deacylase of GPI-Aps in Candida albicans, was critical for GPI-APs cell wall attachment and host infection. BST1-deficient C. albicans (bst1Δ/Δ) was associated with severely impaired cell wall anchorage of GPI-APs and subsequen unmasked β-(1,3)-glucan. Consistent with the aberrant cell wall structures, bst1Δ/Δ strain did not display an invasive ability and could be recognized more efficiently by host immune systems. Moreover, BST1 null mutants or those expressing Bst1 variants did not display inositol deacylation activity and exhibited severely attenuated virulence and reduced organic colonization in a murine systemic candidiasis model. Thus, Bst1 can facilitate cell wall anchorage of GPI-APs in C. albicans by inositol deacylation, and is critical for host invasion and immune escape. PMID:27708385

Commensal–dendritic-cell interaction specifies a unique protective skin immune signature

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Naik, Shruti; Bouladoux, Nicolas; Linehan, Jonathan L.; Han, Seong-Ji; Harrison, Oliver J.; Wilhelm, Christoph; Conlan, Sean; Himmelfarb, Sarah; Byrd, Allyson L.; Deming, Clayton; Quinones, Mariam; Brenchley, Jason M.; Kong, Heidi H.; Tussiwand, Roxanne; Murphy, Kenneth M.; Merad, Miriam; Segre, Julia A; Belkaid, Yasmine

2015-01-01

The skin represents the primary interface between the host and the environment. This organ is also home to trillions of microorganisms that play an important role in tissue homeostasis and local immunity1–4. Skin microbial communities are highly diverse and can be remodelled over time or in response to environmental challenges5–7. How, in the context of this complexity, individual commensal microorganisms may differentially modulate skin immunity and the consequences of these responses for tissue physiology remains unclear. Here we show that defined commensals dominantly affect skin immunity and identify the cellular mediators involved in this specification. In particular, colonization with Staphylococcus epidermidis induces IL-17A+ CD8+ T cells that home to the epidermis, enhance innate barrier immunity and limit pathogen invasion. Commensal-specific T-cell responses result from the coordinated action of skin-resident dendritic cell subsets and are not associated with inflammation, revealing that tissue-resident cells are poised to sense and respond to alterations in microbial communities. This interaction may represent an evolutionary means by which the skin immune system uses fluctuating commensal signals to calibrate barrier immunity and provide heterologous protection against invasive pathogens. These findings reveal that the skin immune landscape is a highly dynamic environment that can be rapidly and specifically remodelled by encounters with defined commensals, findings that have profound implications for our understanding of tissue-specific immunity and pathologies. PMID:25539086

PI5P Triggers ICAM-1 Degradation in Shigella Infected Cells, Thus Dampening Immune Cell Recruitment

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Frédéric Boal

2016-02-01

Full Text Available Shigella flexneri, the pathogen responsible for bacillary dysentery, has evolved multiple strategies to control the inflammatory response. Here, we show that Shigella subverts the subcellular trafficking of the intercellular adhesion molecule-1 (ICAM-1, a key molecule in immune cell recruitment, in a mechanism dependent on the injected bacterial enzyme IpgD and its product, the lipid mediator PI5P. Overexpression of IpgD, but not a phosphatase dead mutant, induced the internalization and the degradation of ICAM-1 in intestinal epithelial cells. Remarkably, addition of permeant PI5P reproduced IpgD effects and led to the inhibition of neutrophil recruitment. Finally, these results were confirmed in an in vivo model of Shigella infection where IpgD-dependent ICAM-1 internalization reduced neutrophil adhesion. In conclusion, we describe here an immune evasion mechanism used by the pathogen Shigella to divert the host cell trafficking machinery in order to reduce immune cell recruitment.

Adaptive immunity alters distinct host feeding pathways during nematode induced inflammation, a novel mechanism in parasite expulsion.

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John J Worthington

2013-01-01

Full Text Available Gastrointestinal infection is often associated with hypophagia and weight loss; however, the precise mechanisms governing these responses remain poorly defined. Furthermore, the possibility that alterations in feeding during infection may be beneficial to the host requires further study. We used the nematode Trichinella spiralis, which transiently inhabits the small intestine before migrating to skeletal muscle, as a biphasic model of infection to determine the cellular and molecular pathways controlling feeding during enteric and peripheral inflammation. Through the infection of genetically modified mice lacking cholecystokinin, Tumor necrosis factor α receptors and T and B-cells, we observed a biphasic hypophagic response to infection resulting from two separate immune-driven mechanisms. The enteroendocrine I-cell derived hormone cholecystokinin is an essential mediator of initial hypophagia and is induced by CD4+ T-cells during enteritis. In contrast, the second hypophagic response is extra-intestinal and due to the anorectic effects of TNFα during peripheral infection of the muscle. Moreover, via maintaining naive levels of the adipose secreted hormone leptin throughout infection we demonstrate a novel feedback loop in the immunoendocrine axis. Immune driven I-cell hyperplasia and resultant weight loss leads to a reduction in the inflammatory adipokine leptin, which in turn heightens protective immunity during infection. These results characterize specific immune mediated mechanisms which reduce feeding during intestinal or peripheral inflammation. Importantly, the molecular mediators of each phase are entirely separate. The data also introduce the first evidence that I-cell hyperplasia is an adaptively driven immune response that directly impinges on the outcome to infection.

Defence mechanisms and immune evasion in the interplay between the humane immune system and Plasmodium falciparum

DEFF Research Database (Denmark)

Theander, T G

1992-01-01

Immunity to P. falciparum malaria is developed as a result of long term exposure to the parasite and depends on immunological memory. The key directors in immune recognition and regulation of the immunological responses are the T-cells. It seems reasonable to propose that immunity is acquired when...... with development of immunity. Several mechanisms seem to be operating. 1) Induction of the immune response to some macromolecules is avoided because the parasites are living inside host cells during part of their life cycle, and the reaction to other molecules is apparently avoided by mimicry of host molecules. 2...

Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

Science.gov (United States)

Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

2018-05-01

The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

DMPD: Macrophage migration inhibitory factor and host innate immune responses tomicrobes. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 14620137 Macrophage migration inhibitory factor and host innate immune responses to...microbes. Calandra T. Scand J Infect Dis. 2003;35(9):573-6. (.png) (.svg) (.html) (.csml) Show Macrophage migration... inhibitory factor and host innate immune responses tomicrobes. PubmedID 14620137 Title Macrophage migration

Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors

Science.gov (United States)

Lozano-Torres, Jose L.; Wilbers, Ruud H. P.; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C.; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

2014-01-01

Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

Science.gov (United States)

Lozano-Torres, Jose L; Wilbers, Ruud H P; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

2014-12-01

Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

Directory of Open Access Journals (Sweden)

Jose L Lozano-Torres

2014-12-01

Full Text Available Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes

The Cell Wall of the Human Fungal Pathogen Aspergillus fumigatus: Biosynthesis, Organization, Immune Response, and Virulence.

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Latgé, Jean-Paul; Beauvais, Anne; Chamilos, Georgios

2017-09-08

More than 90% of the cell wall of the filamentous fungus Aspergillus fumigatus comprises polysaccharides. Biosynthesis of the cell wall polysaccharides is under the control of three types of enzymes: transmembrane synthases, which are anchored to the plasma membrane and use nucleotide sugars as substrates, and cell wall-associated transglycosidases and glycosyl hydrolases, which are responsible for remodeling the de novo synthesized polysaccharides and establishing the three-dimensional structure of the cell wall. For years, the cell wall was considered an inert exoskeleton of the fungal cell. The cell wall is now recognized as a living organelle, since the composition and cellular localization of the different constitutive cell wall components (especially of the outer layers) vary when the fungus senses changes in the external environment. The cell wall plays a major role during infection. The recognition of the fungal cell wall by the host is essential in the initiation of the immune response. The interactions between the different pattern-recognition receptors (PRRs) and cell wall pathogen-associated molecular patterns (PAMPs) orientate the host response toward either fungal death or growth, which would then lead to disease development. Understanding the molecular determinants of the interplay between the cell wall and host immunity is fundamental to combatting Aspergillus diseases.

Maintenance of host leukocytes in peripheral immune compartments following lethal irradiation and bone marrow reconstitution: implications for graft versus host disease.

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Staley, Elizabeth M; Tanner, Scott M; Daft, Joseph G; Stanus, Andrea L; Martin, Steven M; Lorenz, Robin G

2013-03-01

Bone marrow reconstitution is utilized as a tool for disease treatment and as a research technique to elucidate the function of bone marrow derived cells. Clinically successful engraftment is indicated by the development of a functioning immune repertoire. In research, reconstitution is considered successful if >85% of splenic leukocytes are of donor origins. Previous work suggests that splenic reconstitution may not be indicative of reconstitution in the mucosa. We sought to evaluate mucosal reconstitution in animals following a standard bone marrow eradication and reconstitution technique. Bone marrow was harvested from adult B6.SJL donor mice (CD45.1) and injected via either the retro-orbital or intraperitoneal route into lethally irradiated B6 (CD45.2) adult or neonatal recipients respectively. The expression of CD45 by flow cytometry was used to calculate reconstitution with respect to immune compartment and cell type. In reconstituted adult animals 93.2±1.5% of splenic leukocytes expressed the donor CD45.1 antigen thus meeting the standard definition of reconstitution, however only 58.6±13.6% of intestinal lamina propria lymphocytes and 52.4±16.0% of intestinal intraepithelial lymphocytes were of donor origin, confirming splenic reconstitution fails to represent peripheral immune reconstitution. T-cells in the gastrointestinal tract are the most poorly reconstituted, while B-cells appear to be almost universally replaced by donor cells. The inadequate mucosal reconstitution was not corrected by evaluating later time points or by performing the bone marrow transfer during the neonatal period. This demonstration that substantial host T-cells remain in the intestinal mucosa after a "successful" bone marrow transplantation should cause a re-evaluation of data from research bone marrow chimera experiments, as well as the mechanisms for complications after clinical bone marrow transplantation. Copyright © 2013 Elsevier B.V. All rights reserved.

Emerging Evidence for Platelets as Immune and Inflammatory Effector Cells

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Matthew Thomas Rondina

2014-12-01

Full Text Available While traditionally recognized for their roles in hemostatic pathways, emerging evidence demonstrates that platelets have previously unrecognized, dynamic roles that span the immune continuum. These newly-recognized platelet functions, including the secretion of immune mediators, interactions with endothelial cells, monocytes, and neutrophils, toll-like receptor (TLR mediated responses, and induction of neutrophil extracellular trap (NET formation, bridge thrombotic and inflammatory pathways and contribute to host defense mechanisms against invading pathogens. In this focused review, we highlight several of these emerging aspects of platelet biology and their implications in clinical infectious syndromes.

The Pla Protease of Yersinia pestis Degrades Fas Ligand to Manipulate Host Cell Death and Inflammation

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Caulfield, Adam J.; Walker, Margaret E.; Gielda, Lindsay M.; Lathem, Wyndham W.

2014-01-01

SUMMARY Pneumonic plague is a deadly respiratory disease caused by Yersinia pestis. The bacterial protease Pla contributes to disease progression and manipulation of host immunity, but the mechanisms by which this occurs are largely unknown. Here we show that Pla degrades the apoptotic signaling molecule Fas ligand (FasL) to prevent host cell apoptosis and inflammation. Wild-type Y. pestis, but not a Pla mutant (Δpla), degrades FasL, which results in decreased downstream caspase-3/7 activation and reduced apoptosis. Similarly, lungs of mice challenged with wild-type Y. pestis show reduced levels of FasL and activated caspase-3/7 compared to Δpla infection. Consistent with a role for FasL in regulating immune responses, Δpla infection results in aberrant pro-inflammatory cytokine levels. The loss of FasL or inhibition of caspase activity alters host inflammatory responses and enables enhanced Y. pestis outgrowth in the lungs. Thus, by degrading FasL, Y. pestis manipulates host cell death pathways to facilitate infection. PMID:24721571

Self-consuming innate immunity in Arabidopsis

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Hofius, Daniel; Mundy, John; Petersen, Morten

2009-01-01

Programmed cell death (PCD) associated with the pathogen-induced hypersensitive response (HR) is a hallmark of plant innate immunity. HR PCD is triggered upon recognition of pathogen effector molecules by host immune receptors either directly or indirectly via effector modulation of host targets...

Evaluation of host quality of life and immune function in breast cancer patients treated with combination of adjuvant chemotherapy and oral administration of Lentinula edodes mycelia extract

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Nagashima Y

2013-07-01

Full Text Available Yukiko Nagashima,1 Noriko Maeda,2 Shigeru Yamamoto,2 Shigefumi Yoshino,2 Masaaki Oka21Department of Breast and Thyroid Surgery, Shakaihoken Shimonoseki Kosei Hospital, Shimonoseki City, Yamaguchi, Japan; 2Department of Digestive Surgery and Surgical Oncology, Yamaguchi University Graduate School of Medicine, Ube City, Yamaguchi, JapanPurpose: Anthracycline-based chemotherapies for breast cancer are well known to have adverse effects and can also negatively affect host immune function. There is therefore a necessity for an adjuvant that maintains the quality of life (QOL and immune function of cancer patients receiving anthracycline-based chemotherapies.Patients and methods: The present study investigated the effectiveness of the concomitant use of Lentinula edodes mycelia extract (LEM, an oral immunomodulator, with FEC75 (5-fluorouracil + epirubicin + cyclophosphamide therapy on host QOL and immune function in breast cancer patients with nodal metastases. Ten breast cancer patients with nodal metastases receiving surgery were enrolled in this study. Treatment with 5-fluorouracil (500 mg/m2, epirubicin (75 mg/m2, and cyclophosphamide (500 mg/m2 was performed every 21 days for two courses, and LEM (1800 mg/day by mouth was administered during the second course.Results: In the first course, hematological toxicity was observed and host QOL and immune function were exacerbated. In the second course, however, the number of white blood cells and lymphocytes did not decrease and host QOL was maintained. Furthermore, the cytotoxic activities of natural killer (NK and lymphokine-activated killer cells and the proportion of activated NK and NK T-cells in lymphocytes were maintained in the second course.Conclusion: It has been suggested that the concomitant use of LEM with FEC75 therapy can maintain host QOL and immune function, and offer important implications for an application of LEM as a useful oral adjuvant to anthracycline-based chemotherapies

[Exosomes and Immune Cells].

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Seo, Naohiro

2017-05-01

In addition to the cytokines and cytotoxic granules, exosomes have been known as the intercellular communicator and cytotoxic missile of immune cells for the past decade. It has been well known that mature dendritic cell(DC)-derived exosomes participate in the T cell and natural killer(NK)cell activation, while immature DCs secrete tolerogenic exosomes for regulatory T(Treg)cell generation. Treg cell-derived EVs act as a suppressor against pathogenic type-1 T helper(Th1)cell responses. CD8+ T cells produce tumoricidal exosomes for preventing tumor invasion and metastasis transiently after T cell receptor(TCR)-mediated stimulation. Thus, immune cells produce functional exosomes in the activation state- and/or differentiation stage-dependent manner. In this review, the role of immune cell-derived exosomes will be introduced, focusing mainly on immune reaction against tumor.

Symbiotic and antibiotic interactions between gut commensal microbiota and host immune system

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Mantas Kazimieras Malys

2015-01-01

Full Text Available The human gut commensal microbiota forms a complex population of microorganisms that survive by maintaining a symbiotic relationship with the host. Amongst the metabolic benefits it brings, formation of adaptive immune system and maintenance of its homeostasis are functions that play an important role. This review discusses the integral elements of commensal microbiota that stimulate responses of different parts of the immune system and lead to health or disease. It aims to establish conditions and factors that contribute to gut commensal microbiota's transformation from symbiotic to antibiotic relationship with human. We suggest that the host-microbiota relationship has been evolved to benefit both parties and any changes that may lead to disease, are not due to unfriendly properties of the gut microbiota but due to host genetics or environmental changes such as diet or infection.

Immune responses to an encapsulated allogeneic islet β-cell line in diabetic NOD mice

International Nuclear Information System (INIS)

Black, Sasha P.; Constantinidis, Ioannis; Cui, Hong; Tucker-Burden, Carol; Weber, Collin J.; Safley, Susan A.

2006-01-01

Our goal is to develop effective islet grafts for treating type 1 diabetes. Since human islets are scarce, we evaluated the efficacy of a microencapsulated insulin-secreting conditionally transformed allogeneic β-cell line (βTC-tet) in non-obese diabetic mice treated with tetracycline to inhibit cell growth. Relatively low serum levels of tetracycline controlled proliferation of βTC-tet cells without inhibiting effective control of hyperglycemia in recipients. There was no significant host cellular reaction to the allografts or host cell adherence to microcapsules, and host cytokine levels were similar to those of sham-operated controls. We conclude that encapsulated allogeneic β-cell lines may be clinically relevant, because they effectively restore euglycemia and do not elicit a strong cellular immune response following transplantation. To our knowledge, this is First extensive characterization of the kinetics of host cellular and cytokine responses to an encapsulated islet cell line in an animal model of type 1 diabetes

Inhibition of protein geranylgeranylation and farnesylation protects against graft-versus-host disease via effects on CD4 effector T cells.

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Hechinger, Anne-Kathrin; Maas, Kristina; Dürr, Christoph; Leonhardt, Franziska; Prinz, Gabriele; Marks, Reinhard; Gerlach, Ulrike; Hofmann, Maike; Fisch, Paul; Finke, Jürgen; Pircher, Hanspeter; Zeiser, Robert

2013-01-01

Despite advances in immunosuppressive regimens, acute graft-versus-host disease remains a frequent complication of allogeneic hematopoietic cell transplantation. Pathogenic donor T cells are dependent on correct attachment of small GTPases to the cell membrane, mediated by farnesyl- or geranylgeranyl residues, which, therefore, constitute potential targets for graft-versus-host disease prophylaxis. A mouse model was used to study the impact of a farnesyl-transferase inhibitor and a geranylgeranyl-transferase inhibitor on acute graft-versus-host disease, anti-cytomegalovirus T-cell responses and graft-versus-leukemia activity. Treatment of mice undergoing allogeneic hematopoietic cell transplantation with farnesyl-transferase inhibitor and geranylgeranyl-transferase inhibitor reduced the histological severity of graft-versus-host disease and prolonged survival significantly. Mechanistically, farnesyl-transferase inhibitor and geranylgeranyl-transferase inhibitor treatment resulted in reduced alloantigen-driven expansion of CD4 T cells. In vivo treatment led to increased thymic cellularity and polyclonality of the T-cell receptor repertoire by reducing thymic graft-versus-host disease. These effects were absent when squalene production was blocked. The farnesyl-transferase inhibitor and geranylgeranyl-transferase inhibitor did not compromise CD8 function against leukemia cells or reconstitution of T cells that were subsequently responsible for anti-murine cytomegalovirus responses. In summary, we observed an immunomodulatory effect of inhibitors of farnesyl-transferase and geranylgeranyl-transferase on graft-versus-host disease, with enhanced functional immune reconstitution. In the light of the modest toxicity of farnesyl-transferase inhibitors such as tipifarnib in patients and the potent reduction of graft-versus-host disease in mice, farnesyl-transferase and geranylgeranyl-transferase inhibitors could help to reduce graft-versus-host disease significantly without

Interactions between host metabolism, immune regulation, and the gut microbiota in diet-associated obesity and metabolic dysfunction

DEFF Research Database (Denmark)

Andersen, Daniel

The increase in the prevalence of obesity and obesity-associated complications such as the metabolic syndrome is becoming a global challenge. Dietary habits and nutrient consumption modulates host homeostasis, which manifests in various diet-induced complications marked by changes in host...... metabolism and immune regulation, which are intricately linked. In addition, diet effectively shapes the gut microbiota composition and activity, which in turn interacts with the host to modulate host metabolism and immune regulation. In the three studies included in this PhD thesis, we have explored...... the impact of specific dietary components on host metabolic function, immune regulation and gut microbiota composition and activity. In the first study, we have characterized the effect of a combined high-fat and gliadin-rich diet, since dietary gliadin has been reported to be associated with intestinal...

Microsporidia infection impacts the host cell's cycle and reduces host cell apoptosis

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Higes, Mariano; Sagastume, Soledad; Juarranz, Ángeles; Dias-Almeida, Joyce; Budge, Giles E.; Meana, Aránzazu; Boonham, Neil

2017-01-01

Intracellular parasites can alter the cellular machinery of host cells to create a safe haven for their survival. In this regard, microsporidia are obligate intracellular fungal parasites with extremely reduced genomes and hence, they are strongly dependent on their host for energy and resources. To date, there are few studies into host cell manipulation by microsporidia, most of which have focused on morphological aspects. The microsporidia Nosema apis and Nosema ceranae are worldwide parasites of honey bees, infecting their ventricular epithelial cells. In this work, quantitative gene expression and histology were studied to investigate how these two parasites manipulate their host’s cells at the molecular level. Both these microsporidia provoke infection-induced regulation of genes involved in apoptosis and the cell cycle. The up-regulation of buffy (which encodes a pro-survival protein) and BIRC5 (belonging to the Inhibitor Apoptosis protein family) was observed after infection, shedding light on the pathways that these pathogens use to inhibit host cell apoptosis. Curiously, different routes related to cell cycle were modified after infection by each microsporidia. In the case of N. apis, cyclin B1, dacapo and E2F2 were up-regulated, whereas only cyclin E was up-regulated by N. ceranae, in both cases promoting the G1/S phase transition. This is the first report describing molecular pathways related to parasite-host interactions that are probably intended to ensure the parasite’s survival within the cell. PMID:28152065

Ebola virus host cell entry.

Science.gov (United States)

Sakurai, Yasuteru

2015-01-01

Ebola virus is an enveloped virus with filamentous structure and causes a severe hemorrhagic fever in human and nonhuman primates. Host cell entry is the first essential step in the viral life cycle, which has been extensively studied as one of the therapeutic targets. A virus factor of cell entry is a surface glycoprotein (GP), which is an only essential viral protein in the step, as well as the unique particle structure. The virus also interacts with a lot of host factors to successfully enter host cells. Ebola virus at first binds to cell surface proteins and internalizes into cells, followed by trafficking through endosomal vesicles to intracellular acidic compartments. There, host proteases process GPs, which can interact with an intracellular receptor. Then, under an appropriate circumstance, viral and endosomal membranes are fused, which is enhanced by major structural changes of GPs, to complete host cell entry. Recently the basic research of Ebola virus infection mechanism has markedly progressed, largely contributed by identification of host factors and detailed structural analyses of GPs. This article highlights the mechanism of Ebola virus host cell entry, including recent findings.

In vivo Ebola virus infection leads to a strong innate response in circulating immune cells.

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Caballero, Ignacio S; Honko, Anna N; Gire, Stephen K; Winnicki, Sarah M; Melé, Marta; Gerhardinger, Chiara; Lin, Aaron E; Rinn, John L; Sabeti, Pardis C; Hensley, Lisa E; Connor, John H

2016-09-05

Ebola virus is the causative agent of a severe syndrome in humans with a fatality rate that can approach 90 %. During infection, the host immune response is thought to become dysregulated, but the mechanisms through which this happens are not entirely understood. In this study, we analyze RNA sequencing data to determine the host response to Ebola virus infection in circulating immune cells. Approximately half of the 100 genes with the strongest early increases in expression were interferon-stimulated genes, such as ISG15, OAS1, IFIT2, HERC5, MX1 and DHX58. Other highly upregulated genes included cytokines CXCL11, CCL7, IL2RA, IL2R1, IL15RA, and CSF2RB, which have not been previously reported to change during Ebola virus infection. Comparing this response in two different models of exposure (intramuscular and aerosol) revealed a similar signature of infection. The strong innate response in the aerosol model was seen not only in circulating cells, but also in primary and secondary target tissues. Conversely, the innate immune response of vaccinated macaques was almost non-existent. This suggests that the innate response is a major aspect of the cellular response to Ebola virus infection in multiple tissues. Ebola virus causes a severe infection in humans that is associated with high mortality. The host immune response to virus infection is thought to be an important aspect leading to severe pathology, but the components of this overactive response are not well characterized. Here, we analyzed how circulating immune cells respond to the virus and found that there is a strong innate response dependent on active virus replication. This finding is in stark contrast to in vitro evidence showing a suppression of innate immune signaling, and it suggests that the strong innate response we observe in infected animals may be an important contributor to pathogenesis.

Host range, immunity and antigenic properties of lambdoid coliphage HK97.

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Dhillon, E K; Dhillon, T S; Lai, A N; Linn, S

1980-09-01

Temperate coliphage HK97 was isolated from pig dung. Although HK97 is antigenically unrelated to coliphage lambda, it has similar morphology, host range and immunity properties, and can recombine with it.

Apoptotic Cells Induced Signaling for Immune Homeostasis in Macrophages and Dendritic Cells

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Uriel Trahtemberg

2017-10-01

-activated nuclear receptors, Tyro3, Axl, and Mertk receptors, as well as induction of signal transducer and activator of transcription 1 and suppressor of cytokine signaling that lead to immune system silencing and DC tolerance. These properties of apoptotic cells are the mechanisms that enable their successful use as therapeutic modalities in mice and humans in various autoimmune diseases, organ transplantation, graft-versus-host disease, and sepsis.

Herpesvirus microRNAs for use in gene therapy immune-evasion strategies.

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Bots, S T F; Hoeben, R C

2017-07-01

Transplantation of allogeneic cells as well as of genetically corrected autologous cells are potent approaches to restore cellular functions in patients suffering from genetic diseases. The recipient's immune responses against non-self-antigens may compromise the survival of the grafted cells. Recipients of the graft may therefore require lifelong treatment with immunosuppressive drugs. An alternative approach to reduce graft rejection could involve the use of immune-evasion molecules. Expression of such molecules in cells of the graft may subvert recognition by the host's immune system. Viruses in particular are masters of exploitation and modulation of their hosts immune response. The Herpesviridae family provides a proof of concept for this as these viruses are capable to establish latency and a lifelong persistence in the infected hosts. While several viral proteins involved in immune evasion have been characterized, the Herpesviridae also encode a multitude of viral microRNA (miRNAs). Several of these miRNAs have been demonstrated to reduce the sensitivity of the infected cells to the destructive action of the host's immune cells. In this review, the miRNAs of some common herpesviruses that are associated with immune modulation will be discussed with a focus on their potential use in strategies aiming at generating non-immunogenic cells for transplantation.

Resiniferatoxin modulates the Th1 immune response and protects the host during intestinal nematode infection.

Science.gov (United States)

Muñoz-Carrillo, J L; Contreras-Cordero, J F; Muñoz-López, J L; Maldonado-Tapia, C H; Muñoz-Escobedo, J J; Moreno-García, M A

2017-09-01

In the early stage of the intestinal phase of Trichinella spiralis infection, the host triggers a Th1-type immune response with the aim of eliminating the parasite. However, this response damages the host which favours the survival of the parasite. In the search for novel pharmacological strategies that inhibit the Th1 immune response and assist the host against T. spiralis infection, a recent study showed that resiniferatoxin had anti-inflammatory activity contributed to the host in T. spiralis infection. In this study, we evaluated whether RTX modulates the host immune response through the inhibition of Th1 cytokines in the intestinal phase. In addition, it was determined whether the treatment with RTX affects the infectivity of T. spiralis-L1 and the development of the T. spiralis life cycle. Our results show that RTX decreased serum levels of IL-12, INF-γ, IL-1β, TNF-α and parasite burden on muscle tissue. It was observed that T. spiralis-L1 treated with RTX decreased their infectivity affecting the development of the T. spiralis life cycle in mouse. These results demonstrate that RTX is able to inhibit the production of Th1 cytokines, contributing to the defence against T. spiralis, which places it as a potential drug modulator of the immune response. © 2017 John Wiley & Sons Ltd.

Recent Advances in Type-2-Cell-Mediated Immunity: Insights from Helminth Infection.

Science.gov (United States)

Harris, Nicola L; Loke, P'ng

2017-12-19

Type-2-cell-mediated immune responses play a critical role in mediating both host-resistance and disease-tolerance mechanisms during helminth infections. Recently, type 2 cell responses have emerged as major regulators of tissue repair and metabolic homeostasis even under steady-state conditions. In this review, we consider how studies of helminth infection have contributed toward our expanding cellular and molecular understanding of type-2-cell-mediated immunity, as well as new areas such as the microbiome. By studying how these successful parasites form chronic infections without overt pathology, we are gaining additional insights into allergic and inflammatory diseases, as well as normal physiology. Copyright © 2017 Elsevier Inc. All rights reserved.

Proteinaceous molecules mediating Bifidobacterium-host interactions

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Lorena Ruiz

2016-08-01

Full Text Available Bifidobacteria are commensal microoganisms found in the gastrointestinal tract.Several strains have been attributed beneficial traits at local and systemic levels, through pathogen exclusion or immune modulation, among other benefits. This has promoted a growing industrial and scientific interest in bifidobacteria as probiotic supplements. However, the molecular mechanisms mediating this cross-talk with the human host remain unknown. High-throughput technologies, from functional genomics to transcriptomics, proteomics and interactomics coupled to the development of both in vitro and in vivo models to study the dynamics of the intestinal microbiota and their effects on host cells, have eased the identification of key molecules in these interactions. Numerous secreted or surface-associated proteins or peptides have been identified as potential mediators of bifidobacteria-host interactions and molecular cross-talk, directly participating in sensing environmental factors, promoting intestinal colonization or mediating a dialogue with mucosa-associated immune cells. On the other hand, bifidobacteria induce the production of proteins in the intestine, by epithelial or immune cells, and other gut bacteria, which are key elements in orchestrating interactions among bifidobacteria, gut microbiota and host cells. This review aims to give a comprehensive overview on proteinaceous molecules described and characterized to date, as mediators of the dynamic interplay between bifidobacteria and the human host, providing a framework to identify knowledge gaps and future research needs.

The Bacterial Second Messenger Cyclic di-GMP Regulates Brucella Pathogenesis and Leads to Altered Host Immune Response.

Science.gov (United States)

Khan, Mike; Harms, Jerome S; Marim, Fernanda M; Armon, Leah; Hall, Cherisse L; Liu, Yi-Ping; Banai, Menachem; Oliveira, Sergio C; Splitter, Gary A; Smith, Judith A

2016-12-01

Brucella species are facultative intracellular bacteria that cause brucellosis, a chronic debilitating disease significantly impacting global health and prosperity. Much remains to be learned about how Brucella spp. succeed in sabotaging immune host cells and how Brucella spp. respond to environmental challenges. Multiple types of bacteria employ the prokaryotic second messenger cyclic di-GMP (c-di-GMP) to coordinate responses to shifting environments. To determine the role of c-di-GMP in Brucella physiology and in shaping host-Brucella interactions, we utilized c-di-GMP regulatory enzyme deletion mutants. Our results show that a ΔbpdA phosphodiesterase mutant producing excess c-di-GMP displays marked attenuation in vitro and in vivo during later infections. Although c-di-GMP is known to stimulate the innate sensor STING, surprisingly, the ΔbpdA mutant induced a weaker host immune response than did wild-type Brucella or the low-c-di-GMP guanylate cyclase ΔcgsB mutant. Proteomics analysis revealed that c-di-GMP regulates several processes critical for virulence, including cell wall and biofilm formation, nutrient acquisition, and the type IV secretion system. Finally, ΔbpdA mutants exhibited altered morphology and were hypersensitive to nutrient-limiting conditions. In summary, our results indicate a vital role for c-di-GMP in allowing Brucella to successfully navigate stressful and shifting environments to establish intracellular infection. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Trichomonas vaginalis exosomes deliver cargo to host cells and mediate host∶parasite interactions.

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Olivia Twu

Full Text Available Trichomonas vaginalis is a common sexually transmitted parasite that colonizes the human urogential tract where it remains extracellular and adheres to epithelial cells. Infections range from asymptomatic to highly inflammatory, depending on the host and the parasite strain. Here, we use a combination of methodologies including cell fractionation, immunofluorescence and electron microscopy, RNA, proteomic and cytokine analyses and cell adherence assays to examine pathogenic properties of T. vaginalis. We have found that T.vaginalis produces and secretes microvesicles with physical and biochemical properties similar to mammalian exosomes. The parasite-derived exosomes are characterized by the presence of RNA and core, conserved exosomal proteins as well as parasite-specific proteins. We demonstrate that T. vaginalis exosomes fuse with and deliver their contents to host cells and modulate host cell immune responses. Moreover, exosomes from highly adherent parasite strains increase the adherence of poorly adherent parasites to vaginal and prostate epithelial cells. In contrast, exosomes from poorly adherent strains had no measurable effect on parasite adherence. Exosomes from parasite strains that preferentially bind prostate cells increased binding of parasites to these cells relative to vaginal cells. In addition to establishing that parasite exosomes act to modulate host∶parasite interactions, these studies are the first to reveal a potential role for exosomes in promoting parasite∶parasite communication and host cell colonization.

Analyses of Brucella pathogenesis, host immunity, and vaccine targets using systems biology and bioinformatics

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Yongqun eHe

2012-02-01

Full Text Available Brucella is a Gram-negative, facultative intracellular bacterium that causes zoonotic brucellosis in humans and various animals. Out of ten classified Brucella species, B. melitensis, B. abortus, B. suis, and B. canis are pathogenic to humans. In the past decade, the mechanisms of Brucella pathogenesis and host immunity have been extensively investigated using the cutting edge systems biology and bioinformatics approaches. This article provides a comprehensive review of the applications of Omics (including genomics, transcriptomics, and proteomics and bioinformatics technologies for the analysis of Brucella pathogenesis, host immune responses, and vaccine targets. Based on more than 30 sequenced Brucella genomes, comparative genomics is able to identify gene variations among Brucella strains that help to explain host specificity and virulence differences among Brucella species. Diverse transcriptomics and proteomics gene expression studies have been conducted to analyze gene expression profiles of wild type Brucella strains and mutants under different laboratory conditions. High throughput Omics analyses of host responses to infections with virulent or attenuated Brucella strains have been focused on responses by mouse and cattle macrophages, bovine trophoblastic cells, mouse and boar splenocytes, and ram buffy coat. Differential serum responses in humans and rams to Brucella infections have been analyzed using high throughput serum antibody screening technology. The Vaxign reverse vaccinology has been used to predict many Brucella vaccine targets. More than 180 Brucella virulence factors and their gene interaction networks have been identified using advanced literature mining methods. The recent development of community-based Vaccine Ontology and Brucellosis Ontology provides an efficient way for Brucella data integration, exchange, and computer-assisted automated reasoning.

Analyses of Brucella Pathogenesis, Host Immunity, and Vaccine Targets using Systems Biology and Bioinformatics

Science.gov (United States)

He, Yongqun

2011-01-01

Brucella is a Gram-negative, facultative intracellular bacterium that causes zoonotic brucellosis in humans and various animals. Out of 10 classified Brucella species, B. melitensis, B. abortus, B. suis, and B. canis are pathogenic to humans. In the past decade, the mechanisms of Brucella pathogenesis and host immunity have been extensively investigated using the cutting edge systems biology and bioinformatics approaches. This article provides a comprehensive review of the applications of Omics (including genomics, transcriptomics, and proteomics) and bioinformatics technologies for the analysis of Brucella pathogenesis, host immune responses, and vaccine targets. Based on more than 30 sequenced Brucella genomes, comparative genomics is able to identify gene variations among Brucella strains that help to explain host specificity and virulence differences among Brucella species. Diverse transcriptomics and proteomics gene expression studies have been conducted to analyze gene expression profiles of wild type Brucella strains and mutants under different laboratory conditions. High throughput Omics analyses of host responses to infections with virulent or attenuated Brucella strains have been focused on responses by mouse and cattle macrophages, bovine trophoblastic cells, mouse and boar splenocytes, and ram buffy coat. Differential serum responses in humans and rams to Brucella infections have been analyzed using high throughput serum antibody screening technology. The Vaxign reverse vaccinology has been used to predict many Brucella vaccine targets. More than 180 Brucella virulence factors and their gene interaction networks have been identified using advanced literature mining methods. The recent development of community-based Vaccine Ontology and Brucellosis Ontology provides an efficient way for Brucella data integration, exchange, and computer-assisted automated reasoning. PMID:22919594

Tumor - host immune interactions in Ewing sarcoma : implications for therapy

NARCIS (Netherlands)

Berghuis, Dagmar

2012-01-01

In this thesis, we report on various aspects of tumor - host (immune) interactions in Ewing sarcoma patients with the aim to obtain leads for immunotherapeutic or targeted treatment strategies. We demonstrate a key role for interferon gamma (IFNg) in enhancing both Ewing sarcoma immunogenicity and

Anaplasma phagocytophilum MSP4 and HSP70 Proteins Are Involved in Interactions with Host Cells during Pathogen Infection

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Marinela Contreras

2017-07-01

Full Text Available Anaplasma phagocytophilum transmembrane and surface proteins play a role during infection and multiplication in host neutrophils and tick vector cells. Recently, A. phagocytophilum Major surface protein 4 (MSP4 and Heat shock protein 70 (HSP70 were shown to be localized on the bacterial membrane, with a possible role during pathogen infection in ticks. In this study, we hypothesized that A. phagocytophilum MSP4 and HSP70 have similar functions in tick-pathogen and host-pathogen interactions. To address this hypothesis, herein we characterized the role of these bacterial proteins in interaction and infection of vertebrate host cells. The results showed that A. phagocytophilum MSP4 and HSP70 are involved in host-pathogen interactions, with a role for HSP70 during pathogen infection. The analysis of the potential protective capacity of MSP4 and MSP4-HSP70 antigens in immunized sheep showed that MSP4-HSP70 was only partially protective against pathogen infection. This limited protection may be associated with several factors, including the recognition of non-protective epitopes by IgG in immunized lambs. Nevertheless, these antigens may be combined with other candidate protective antigens for the development of vaccines for the control of human and animal granulocytic anaplasmosis. Focusing on the characterization of host protective immune mechanisms and protein-protein interactions at the host-pathogen interface may lead to the discovery and design of new effective protective antigens.

Comparison of innate and Th1-type host immune responses inOesophagostomum dentatumandTrichuris suisinfections in pigs

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Andreasen, Annette; Skovgaard, Kerstin; Klaver, Elsenoor J.

2016-01-01

with two groups trickle inoculated with 10 T. suis eggs/kg/day (Group T) or 20 O. dentatum L3/kg/day (O). Another group (OT) was infected with both parasites. Group C remained uninfected. Expression of innate and Th1/Treg cell associated genes in gut mucosa and associated lymph nodes was determined by q....... Surprisingly, O. dentatum E/S products induced a significant (p helminth-host immune response interaction....

Immune Evasion Mechanisms of Entamoeba histolytica: Progression to Disease.

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Begum, Sharmin; Quach, Jeanie; Chadee, Kris

2015-01-01

Entamoeba histolytica (Eh) is a protozoan parasite that infects 10% of the world's population and results in 100,000 deaths/year from amebic dysentery and/or liver abscess. In most cases, this extracellular parasite colonizes the colon by high affinity binding to MUC2 mucin without disease symptoms, whereas in some cases, Eh triggers an aggressive inflammatory response upon invasion of the colonic mucosa. The specific host-parasite factors critical for disease pathogenesis are still not well characterized. From the parasite, the signature events that lead to disease progression are cysteine protease cleavage of the C-terminus of MUC2 that dissolves the mucus layer followed by Eh binding and cytotoxicity of the mucosal epithelium. The host mounts an ineffective excessive host pro-inflammatory response following contact with host cells that causes tissue damage and participates in disease pathogenesis as Eh escapes host immune clearance by mechanisms that are not completely understood. Ameba can modulate or destroy effector immune cells by inducing neutrophil apoptosis and suppressing respiratory burst or nitric oxide (NO) production from macrophages. Eh adherence to the host cells also induce multiple cytotoxic effects that can promote cell death through phagocytosis, apoptosis or by trogocytosis (ingestion of living cells) that might play critical roles in immune evasion. This review focuses on the immune evasion mechanisms that Eh uses to survive and induce disease manifestation in the host.

The entomopathogenic fungus Nomuraea rileyi impairs cellular immunity of its host Helicoverpa armigera.

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Zhong, Ke; Liu, Zhan-Chi; Wang, Jia-Lin; Liu, Xu-Sheng

2017-09-01

In this study, we investigated the effect of the entomopathogenic fungus Nomuraea rileyi on Helicoverpa armigera cellular immune responses. Nomuraea rileyi infection had no effect on total hemocyte count (THC), but impaired hemocyte-mediated phagocytosis, nodulation, and encapsulation responses. Nomuraea rileyi infection led to a significant reduction in hemocyte spreading. An in vitro assay revealed that plasma from N. rileyi infected H. armigera larvae suppressed the spreading ability of hemocytes from naïve larvae. We infer that N. rileyi suppresses the cellular immune response of its host, possibly by secreting exogenous, cytotoxic compounds into the host's hemolymph. © 2017 Wiley Periodicals, Inc.

Lymphotoxin organizes contributions to host defense and metabolic illness from innate lymphoid cells.

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Upadhyay, Vaibhav; Fu, Yang-Xin

2014-04-01

The lymphotoxin (LT)-pathway is a unique constituent branch of the Tumor Necrosis Superfamily (TNFSF). Use of LT is a critical mechanism by which fetal innate lymphoid cells regulate lymphoid organogenesis. Within recent years, adult innate lymphoid cells have been discovered to utilize this same pathway to regulate IL-22 and IL-23 production for host defense. Notably, genetic studies have linked polymorphisms in the genes encoding LTα to several phenotypes contributing to metabolic syndrome. The role of the LT-pathway may lay the foundation for a bridge between host immune response, microbiota, and metabolic syndrome. The contribution of the LT-pathway to innate lymphoid cell function and metabolic syndrome will be visited in this review. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mycobacterium leprae–host-cell interactions and genetic determinants in leprosy: an overview

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Pinheiro, Roberta Olmo; de Souza Salles, Jorgenilce; Sarno, Euzenir Nunes; Sampaio, Elizabeth Pereira

2011-01-01

Leprosy, also known as Hansen’s disease, is a chronic infectious disease caused by Mycobacterium leprae in which susceptibility to the mycobacteria and its clinical manifestations are attributed to the host immune response. Even though leprosy prevalence has decreased dramatically, the high number of new cases indicates active transmission. Owing to its singular features, M. leprae infection is an attractive model for investigating the regulation of human immune responses to pathogen-induced disease. Leprosy is one of the most common causes of nontraumatic peripheral neuropathy worldwide. The proportion of patients with disabilities is affected by the type of leprosy and delay in diagnosis. This article briefly reviews the clinical features as well as the immunopathological mechanisms related to the establishment of the different polar forms of leprosy, the mechanisms related to M. leprae–host cell interactions and prophylaxis and diagnosis of this complex disease. Host genetic factors are summarized and the impact of the development of interventions that prevent, reverse or limit leprosy-related nerve impairments are discussed. PMID:21366421

Modelling parasite transmission in a grazing system: the importance of host behaviour and immunity.

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Naomi J Fox

Full Text Available Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts' immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites' free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes

Pathogens and host immunity in the ancient human oral cavity

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Warinner, Christina; Matias Rodrigues, João F.; Vyas, Rounak; Trachsel, Christian; Shved, Natallia; Grossmann, Jonas; Radini, Anita; Hancock, Y.; Tito, Raul Y.; Fiddyment, Sarah; Speller, Camilla; Hendy, Jessica; Charlton, Sophy; Luder, Hans Ulrich; Salazar-García, Domingo C.; Eppler, Elisabeth; Seiler, Roger; Hansen, Lars; Samaniego Castruita, José Alfredo; Barkow-Oesterreicher, Simon; Teoh, Kai Yik; Kelstrup, Christian; Olsen, Jesper V.; Nanni, Paolo; Kawai, Toshihisa; Willerslev, Eske; von Mering, Christian; Lewis, Cecil M.; Collins, Matthew J.; Gilbert, M. Thomas P.; Rühli, Frank; Cappellini, Enrico

2014-01-01

Calcified dental plaque (dental calculus) preserves for millennia and entraps biomolecules from all domains of life and viruses. We report the first high-resolution taxonomic and protein functional characterization of the ancient oral microbiome and demonstrate that the oral cavity has long served as a reservoir for bacteria implicated in both local and systemic disease. We characterize: (i) the ancient oral microbiome in a diseased state, (ii) 40 opportunistic pathogens, (iii) the first evidence of ancient human-associated putative antibiotic resistance genes, (iv) a genome reconstruction of the periodontal pathogen Tannerella forsythia, (v) 239 bacterial and 43 human proteins, allowing confirmation of a long-term association between host immune factors, “red-complex” pathogens, and periodontal disease, and (vi) DNA sequences matching dietary sources. Directly datable and nearly ubiquitous, dental calculus permits the simultaneous investigation of pathogen activity, host immunity, and diet, thereby extending the direct investigation of common diseases into the human evolutionary past. PMID:24562188

Group 3 Innate Lymphoid Cells: Communications Hubs of the Intestinal Immune System.

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Withers, David R; Hepworth, Matthew R

2017-01-01

The maintenance of mammalian health requires the generation of appropriate immune responses against a broad range of environmental and microbial challenges, which are continually encountered at barrier tissue sites including the skin, lung, and gastrointestinal tract. Dysregulated barrier immune responses result in inflammation, both locally and systemically in peripheral organs. Group 3 innate lymphoid cells (ILC3) are constitutively present at barrier sites and appear to be highly specialized in their ability to sense a range of environmental and host-derived signals. Under homeostatic conditions, ILC3 respond to local cues to maintain tissue homeostasis and restrict inflammatory responses. In contrast, perturbations in the tissue microenvironment resulting from disease, infection, or tissue damage can drive dysregulated pro-inflammatory ILC3 responses and contribute to immunopathology. The tone of the ILC3 response is dictated by a balance of "exogenous" signals, such as dietary metabolites and commensal microbes, and "endogenous" host-derived signals from stromal cells, immune cells, and the nervous system. ILC3 must therefore have the capacity to simultaneously integrate a wide array of complex and dynamic inputs in order to regulate barrier function and tissue health. In this review, we discuss the concept of ILC3 as a "communications hub" in the intestinal tract and associated lymphoid tissues and address the variety of signals, derived from multiple biological systems, which are interpreted by ILC3 to modulate the release of downstream effector molecules and regulate cell-cell crosstalk. Successful integration of environmental cues by ILC3 and downstream propagation to the broader immune system is required to maintain a tolerogenic and anti-inflammatory tone and reinforce barrier function, whereas dysregulation of ILC3 responses can contribute to the onset or progression of clinically relevant chronic inflammatory diseases.

Friends and foes of tuberculosis: modulation of protective immunity.

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Brighenti, Susanna; Joosten, Simone A

2018-05-27

Protective immunity in tuberculosis (TB) is subject of debate in the TB research community, as this is key to fully understand TB pathogenesis and to develop new promising tools for TB diagnosis and prognosis as well as a more efficient TB vaccine. IFN-γ producing CD4 + T cells are key in TB control, but may not be sufficient to provide protection. Additional subsets have been identified that contribute to protection such as multifunctional and cytolytic T cell subsets, including classical and non-classical T cells as well as novel innate immune cell subsets resulting from trained immunity. However, to define protective immune responses against TB, the complexity of balancing TB immunity also has to be considered. In this review, insights in effector cell immunity and how this is modulated by regulatory cells, associated comorbidities and the host microbiome is discussed. We systematically map how different suppressive immune cell subsets may affect effector cell responses at the local site of infection. We also dissect how common co-morbidities such as HIV, helminthes and diabetes may bias protective TB immunity towards pathogenic and regulatory responses. Finally, also the composition and diversity of the microbiome in the lung and gut could affect host TB immunity. Understanding these various aspects of the immunological balance in the human host is fundamental to prevent TB infection and disease. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The Paracoccidioides cell wall: past and present layers towards understanding interaction with the host

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Rosana ePuccia

2011-12-01

Full Text Available The cell wall of pathogenic fungi plays import roles in interaction with the host, so that its composition and structure may determine the course of infection. Here we present an overview of the current and past knowledge on the cell wall constituents of Paracoccidioides brasiliensis and P. lutzii. These are temperature-dependent dimorphic fungi that cause paracoccidioidomycosis, a systemic granulomatous and debilitating disease. Focus is given on cell wall carbohydrate and protein contents, their immune-stimulatory features, adhesion properties, drug target characteristics, and morphological phase specificity. We offer a journey towards the future understanding of the dynamic life that takes place in the cell wall and of the changes that it may suffer when living in the human host.

As-CATH1-6, novel cathelicidins with potent antimicrobial and immunomodulatory properties from Alligator sinensis, play pivotal roles in host antimicrobial immune responses.

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Chen, Yan; Cai, Shasha; Qiao, Xue; Wu, Mali; Guo, Zhilai; Wang, Renping; Kuang, Yi-Qun; Yu, Haining; Wang, Yipeng

2017-08-10

Crocodilians are regarded as possessing a powerful immune system. However, the composition and action of the crocodilian immune system have remained unclear until now. Cathelicidins, the principal family of host defense peptides, play pivotal roles in vertebrate immune defense against microbial invasions. However, cathelicidins from crocodilians have not been extensively studied to date. In the present study, six novel cathelicidins (As-CATH1-6) were identified and characterized from the endangered Chinese alligator ( Alligator sinensis ). As-CATH1-6 exhibit no sequence similarity with any of the known cathelicidins. Structure analysis indicated that As-CATH1-3 adopt a random coil secondary conformation, whereas As-CATH4-6 were predicted to mainly adopt an amphipathic α-helix conformation. Among them, As-CATH4-6 exhibited potent, broad-spectrum and rapid antimicrobial activity by inducing the disruption of cell membrane integrity. They also exhibited strong ability to prevent the formation of bacterial biofilms and eradicate preformed biofilms. Furthermore, As-CATH4-6 exhibited potent anti-inflammatory activity by inhibiting the lipopolysaccharide (LPS)-induced production of nitric oxide (NO) and pro-inflammatory cytokines in mouse peritoneal macrophages. They directly neutralized LPS toxicity and therefore inhibited the binding of LPS to the TLR4 receptor and the subsequent activation of inflammatory response pathways. In a peritonitis mice model, As-CATH2-6 provided effective protection against bacterial infection through enhanced immune cell recruitment. In the host Chinese alligator, As-CATH1-6 are mainly expressed in immune organs and epithelial tissues. Bacterial infection significantly enhances their expression, which implies an important role in host anti-infective response. Taken together, the diversity and multiple functions of As-CATH1-6 partially reveal the powerful immune system of the Chinese alligator. © 2017 The Author(s). Published by Portland

The Value of a Comparative Approach to Understand the Complex Interplay between Microbiota and Host Immunity

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Norma M. Morella

2017-09-01

Full Text Available The eukaryote immune system evolved and continues to evolve within a microbial world, and as such is critically shaped by—and in some cases even reliant upon—the presence of host-associated microbial species. There are clear examples of adaptations that allow the host to simultaneously tolerate and/or promote growth of symbiotic microbiota while protecting itself against pathogens, but the relationship between immunity and the microbiome reaches far beyond simple recognition and includes complex cross talk between host and microbe as well as direct microbiome-mediated protection against pathogens. Here, we present a broad but brief overview of how the microbiome is controlled by and interacts with diverse immune systems, with the goal of identifying questions that can be better addressed by taking a comparative approach across plants and animals and different types of immunity. As two key examples of such an approach, we focus on data examining the importance of early exposure on microbiome tolerance and immune system development and function, and the importance of transmission among hosts in shaping the potential coevolution between, and long-term stability of, host–microbiome associations. Then, by comparing existing evidence across short-lived plants, mouse model systems and humans, and insects, we highlight areas of microbiome research that are strong in some systems and absent in others with the hope of guiding future research that will allow for broad-scale comparisons moving forward. We argue that such an approach will not only help with identification of generalities in host–microbiome–immune interactions but also improve our understanding of the role of the microbiome in host health.

Exploitation of the host cell ubiquitin machinery by microbial effector proteins.

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Lin, Yi-Han; Machner, Matthias P

2017-06-15

Pathogenic bacteria are in a constant battle for survival with their host. In order to gain a competitive edge, they employ a variety of sophisticated strategies that allow them to modify conserved host cell processes in ways that favor bacterial survival and growth. Ubiquitylation, the covalent attachment of the small modifier ubiquitin to target proteins, is such a pathway. Ubiquitylation profoundly alters the fate of a myriad of cellular proteins by inducing changes in their stability or function, subcellular localization or interaction with other proteins. Given the importance of ubiquitylation in cell development, protein homeostasis and innate immunity, it is not surprising that this post-translational modification is exploited by a variety of effector proteins from microbial pathogens. Here, we highlight recent advances in our understanding of the many ways microbes take advantage of host ubiquitylation, along with some surprising deviations from the canonical theme. The lessons learned from the in-depth analyses of these host-pathogen interactions provide a fresh perspective on an ancient post-translational modification that we thought was well understood.This article is part of a Minifocus on Ubiquitin Regulation and Function. For further reading, please see related articles: 'Mechanisms of regulation and diversification of deubiquitylating enzyme function' by Pawel Leznicki and Yogesh Kulathu ( J. Cell Sci. 130 , 1997-2006). 'Cell scientist to watch - Mads Gyrd-Hansen' ( J. Cell Sci. 130 , 1981-1983). © 2017. Published by The Company of Biologists Ltd.

Pregnancy immunology: decidual immune cells.

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Sanguansermsri, Donruedee; Pongcharoen, Sutatip

2008-01-01

Human pregnancy is a complex process. Placental development depends on the function of secretory molecules produced by placental trophoblast cells as well as by maternal uterine immune cells within the decidua. These decidual immune cells are T cells, natural killer cells, macrophages and dendritic cells. The interactions between the trophoblast cells and the maternal immune cells have an impact on the outcome of the pregnancy. Knowledge about the phenotypes and functions of the maternal immune cells in normal and pathological pregnancies including recurrent spontaneous abortions, preeclampsia and hydatidiform moles may improve our understanding of the immunobiology of the normal pregnancy as a whole and may provide approaches for improving the treatment of pathological pregnancies.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells.

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Bandoła, Joanna; Richter, Cornelia; Ryser, Martin; Jamal, Arshad; Ashton, Michelle P; von Bonin, Malte; Kuhn, Matthias; Dorschner, Benjamin; Alexopoulou, Dimitra; Navratiel, Katrin; Roeder, Ingo; Dahl, Andreas; Hedrich, Christian M; Bonifacio, Ezio; Brenner, Sebastian; Thieme, Sebastian

2017-01-01

Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells

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Joanna Bandoła

2017-08-01

Full Text Available Plasmacytoid dendritic cells (pDCs regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR by the antigen-presenting pDCs, mediated by toll-like receptor (TLR 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Both live and dead Enterococci activate Caenorhabditis elegans host defense via immune and stress pathways.

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Yuen, Grace J; Ausubel, Frederick M

2018-12-31

The innate immune response of the nematode Caenorhabditis elegans has been extensively studied and a variety of Toll-independent immune response pathways have been identified. Surprisingly little, however, is known about how pathogens activate the C. elegans immune response. Enterococcus faecalis and Enterococcus faecium are closely related enterococcal species that exhibit significantly different levels of virulence in C. elegans infection models. Previous work has shown that activation of the C. elegans immune response by Pseudomonas aeruginosa involves P. aeruginosa-mediated host damage. Through ultrastructural imaging, we report that infection with either E. faecalis or E. faecium causes the worm intestine to become distended with proliferating bacteria in the absence of extensive morphological changes and apparent physical damage. Genetic analysis, whole-genome transcriptional profiling, and multiplexed gene expression analysis demonstrate that both enterococcal species, whether live or dead, induce a rapid and similar transcriptional defense response dependent upon previously described immune signaling pathways. The host response to E. faecium shows a stricter dependence upon stress response signaling pathways than the response to E. faecalis. Unexpectedly, we find that E. faecium is a C. elegans pathogen and that an active wild-type host defense response is required to keep an E. faecium infection at bay. These results provide new insights into the mechanisms underlying the C. elegans immune response to pathogen infection.

History of myeloid derived suppressor cells (MDSCs) in the macro- and micro-environment of tumour-bearing hosts

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Talmadge, James E.; Gabrilovich, Dmitry I.

2015-01-01

Tumour-induced granulocytic hyperplasia is associated with tumour vasculogenesis and escape from immunity via T-cell suppression. Initially, these myeloid cells were identified as granulocytes or monocytes; however, recent studies revealed that this hyperplasia was associated with populations of multi-potent progenitor cells identified as myeloid-derived suppressor cells (MDSCs). The discovery and study of MDSCs have provided a wealth of information regarding tumour pathobiology, extended our understanding of neoplastic progression, and modified our approaches to immune adjuvant therapy. In this perspective, we discuss the history of MDSCs, their influence on tumour progression and metastasis, and the crosstalk between tumour cells, MDSCs, and the host macroenvironment. PMID:24060865

Mouse Model of Devil Facial Tumour Disease establishes that an effective immune response can be generated against the cancer cells

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Terry L Pinfold

2014-05-01

Full Text Available The largest carnivorous marsupial in Australia, the Tasmanian devil (Sarcophilus harrisii is facing extinction in the wild due to a transmissible cancer known as Devil Facial Tumour Disease (DFTD. DFTD is a clonal cell line transmitted from host to host with 100% mortality and no known immunity. While it was first considered that low genetic diversity of the population of devils enabled the allograft transmission of DFTD recent evidence reveals that genetically diverse animals succumb to the disease. The lack of an immune response against the DFTD tumor cells may be due to a lack of immunogenicity of the tumor cells. This could facilitate transmission between devils. To test immunogenicity, mice were injected with viable DFTD cells and anti-DFTD immune responses analyzed. A range of antibody isotypes against DFTD cells was detected, indicating that as DFTD cells can induce an immune response they are immunogenic. This was supported by cytokine production, when splenocytes from mice injected with DFTD cells were cultured in vitro with DFTD cells and the supernatant analyzed. There was a significant production of IFN-γ and TNF-α following the first injection with DFTD cells and a significant production of IL-6 and IL-10 following the second injection. Splenocytes from naïve or immunized mice killed DFTD cells in in vitro cytotoxicity assays. Thus they are also targets for immunological destruction. We conclude that as an immune response can be generated against DFTD cells they would be suitable targets for a vaccine.

HumanViCe: Host ceRNA network in virus infected cells in human

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Suman eGhosal

2014-07-01

Full Text Available Host-virus interaction via host cellular components has been an important field of research in recent times. RNA interference mediated by short interfering RNAs and microRNAs (miRNA, is a widespread anti-viral defence strategy. Importantly, viruses also encode their own miRNAs. In recent times miRNAs were identified as key players in host-virus interaction. Furthermore, viruses were shown to exploit the host miRNA networks to suite their own need. The complex cross-talk between host and viral miRNAs and their cellular and viral targets forms the environment for viral pathogenesis. Apart from protein-coding mRNAs, non-coding RNAs may also be targeted by host or viral miRNAs in virus infected cells, and viruses can exploit the host miRNA mediated gene regulatory network via the competing endogenous RNA effect. A recent report showed that viral U-rich non-coding RNAs called HSUR, expressed in primate virus herpesvirus saimiri (HVS infected T cells, were able to bind to three host miRNAs, causing significant alteration in cellular level for one of the miRNAs. We have predicted protein coding and non protein-coding targets for viral and human miRNAs in virus infected cells. We identified viral miRNA targets within host non-coding RNA loci from AGO interacting regions in three different virus infected cells. Gene ontology (GO and pathway enrichment analysis of the genes comprising the ceRNA networks in the virus infected cells revealed enrichment of key cellular signalling pathways related to cell fate decisions and gene transcription, like Notch and Wnt signalling pathways, as well as pathways related to viral entry, replication and virulence. We identified a vast number of non-coding transcripts playing as potential ceRNAs to the immune response associated genes; e.g. APOBEC family genes, in some virus infected cells. All these information are compiled in HumanViCe, a comprehensive database that provides the potential ceRNA networks in virus

CD8+ T cells provide immune protection against murine disseminated endotheliotropic Orientia tsutsugamushi infection.

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Guang Xu

2017-07-01

Full Text Available Scrub typhus, caused by a Gram-negative obligately intracellular coccobacillus, Orientia tsutsugamushi, is a long neglected but important tropical disease. Orientia tsutsugamushi causes illness in one million people each year, and 1 billion people are at risk. Without appropriate diagnosis and treatment, the disease can cause severe multiorgan failure with a case fatality rate of 7-15%. The current gaps in knowledge of immunity include the unknown mechanisms of host immunity to O. tsutsugamushi. Using an intravenous (i.v. disseminated infection mouse model, we observed that more CD8+ T cells than CD4+ T cells were present in the spleen of infected mice at 12 dpi. We also determined that Treg cells and the proportion of T cells producing IL-10 were significantly increased from 6 dpi, which correlated with the onset of illness, body weight loss, and increased bacterial loads. We further studied CD8-/-, MHC I-/- and wild type control (WT C57BL/6J mice to determine the importance of CD8+ T cells and MHC I molecules. After infection with an ordinarily sub-lethal dose of O. tsutsugamushi, all CD8-/- and MHC I-/- mice were moribund between 12 and 15 dpi, whereas all WT mice survived. Bacterial loads in the lung, kidney, liver and spleen of CD8-/- and MHC I-/- mice were significantly greater than those in WT mice. Interferon-γ (IFN-γ and granzyme B mRNA levels in the liver of CD8-/- and MHC I-/- mice were significantly greater than in WT mice. In addition, more severe histopathologic lesions were observed in CD8-/- mice. Finally, adoptive transfer confirmed a major role of immune CD8+ T cells as well as a less effective contribution by immune CD8 T cell-depleted splenocytes in protection against O. tsutsugamushi infection. These studies demonstrated the critical importance of CD8+ T cells in the host immune response during O. tsutsugamushi infection.

Unfolding Role of a Danger Molecule Adenosine Signaling in Modulation of Microbial Infection and Host Cell Response

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Jaden S. Lee

2018-01-01

Full Text Available Ectonucleotidases CD39 and CD73, specific nucleotide metabolizing enzymes located on the surface of the host, can convert a pro-inflammatory environment driven by a danger molecule extracellular-ATP to an adenosine-mediated anti-inflammatory milieu. Accordingly, CD39/CD73 signaling has been strongly implicated in modulating the intensity, duration, and composition of purinergic danger signals delivered to host. Recent studies have eluted potential roles for CD39 and CD73 in selective triggering of a variety of host immune cells and molecules in the presence of pathogenic microorganisms or microbial virulence molecules. Growing evidence also suggests that CD39 and CD73 present complimentary, but likely differential, actions against pathogens to shape the course and severity of microbial infection as well as the associated immune response. Similarly, adenosine receptors A2A and A2B have been proposed to be major immunomodulators of adenosine signaling during chronic inflammatory conditions induced by opportunistic pathogens, such as oral colonizer Porphyromonas gingivalis. Therefore, we here review the recent studies that demonstrate how complex network of molecules in the extracellular adenosine signaling machinery and their interactions can reshape immune responses and may also be targeted by opportunistic pathogens to establish successful colonization in human mucosal tissues and modulate the host immune response.

T cell-derived Lymphotoxin is Essential for anti-HSV-1 Humoral Immune Response.

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Yang, Kaiting; Liang, Yong; Sun, Zhichen; Xue, Diyuan; Xu, Hairong; Zhu, Mingzhao; Fu, Yang-Xin; Peng, Hua

2018-05-09

B cell-derived lymphotoxin (LT) is required for the development of follicular dendritic cell clusters for the formation of primary and secondary lymphoid follicles, but the role of T cell-derived LT in antibody response has not been well demonstrated. We observed that lymphotoxin-β-receptor (LTβR) signaling is essential for optimal humoral immune response and protection against an acute HSV-1 infection. Blocking the LTβR pathway caused poor maintenance of germinal center B (GC-B) cells and follicular helper T (Tfh) cells. Using bone marrow chimeric mice and adoptive transplantation, we determined that T cell-derived LT played an indispensable role in the humoral immune response to HSV-1. Up-regulation of IFNγ by the LTβR-Ig blockade impairs the sustainability of Tfh-like cells, thus leading to an impaired humoral immune response. Our findings have identified a novel role of T cell-derived LT in the humoral immune response against HSV-1 infection. IMPORTANCE Immunocompromised people are susceptible for HSV-1 infection and lethal recurrence, which could be inhibited by anti-HSV-1 humoral immune response in the host. This study sought to explore the role of T cell-derived LT in the anti-HSV-1 humoral immune response using LT-LTβR signaling deficient mice and the LTβR-Ig blockade. The data indicate that the T cell-derived LT may play an essential role in sustaining Tfh-like cells and ensure Tfh-like cells' migration into primary or secondary follicles for further maturation. This study provides insights for vaccine development against infectious diseases. Copyright © 2018 American Society for Microbiology.

Type 2 immunity and wound healing: evolutionary refinement of adaptive immunity by helminths

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Gause, William C.; Wynn, Thomas A.; Allen, Judith E.

2013-01-01

Helminth-induced type 2 immune responses, which are characterized by the T helper 2 cell-associated cytokines interleukin-4 (IL-4) and IL-13, mediate host protection through enhanced tissue repair, the control of inflammation and worm expulsion. In this Opinion article, we consider type 2 immunity in the context of helminth-mediated tissue damage. We examine the relationship between the control of helminth infection and the mechanisms of wound repair, and we provide a new understanding of the adaptive type 2 immune response and its contribution to both host tolerance and resistance. PMID:23827958

Immune evasion mechanisms of Entamoeba histolytica: progression to disease

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Sharmin eBegum

2015-12-01

Full Text Available Entamoeba histolytica (Eh is a protozoan parasite that infects 10% of the world’s population and results in 100,000 deaths/year from amebic dysentery and/or liver abscess. In most cases, this extracellular parasite colonizes the colon by high affinity binding to MUC2 mucin without disease symptoms, whereas in some cases, Eh triggers an aggressive inflammatory response upon invasion of the colonic mucosa. The specific host-parasite factors critical for disease pathogenesis are still not well characterized. From the parasite, the signature events that lead to disease progression are cysteine protease cleavage of the C-terminus of MUC2 that dissolves the mucus layer followed by Eh binding and cytotoxicity of the mucosal epithelium. The host mounts an ineffective excessive host pro-inflammatory response following contact with host cells that causes tissue damage and participates in disease pathogenesis as Eh escapes host immune clearance by mechanisms that are not completely understood. Ameba can modulate or destroy effector immune cells by inducing neutrophil apoptosis and suppressing respiratory burst or nitric oxide (NO production from macrophages. Eh adherence to the host cells also induce multiple cytotoxic effects that can promote cell death through phagocytosis, apoptosis or by trogocytosis (ingestion of living cells that might play critical roles in immune evasion. This review focuses on the immune evasion mechanisms that Eh uses to survive and induce disease manifestation in the host.

The percentage of iNKT cells among other immune cells at various clinical stages of laryngeal cancer

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Janusz Klatka

2016-04-01

Full Text Available Introduction: Invariant natural killer T (iNKT cells constitute a small population of immune cells that share functional and phenotypic characteristics of T lymphocytes and NK cells. Due to their involvement in specific and non-specific immune responses, iNKT cells may represent an important component of antitumor and anti-infectious immunity. Material and methods: Using flow cytometry, we analyzed the percentages of iNKT cells as well as T and B lymphocytes in peripheral blood of 50 laryngeal cancer patients at various clinical stages in comparison to healthy controls (n=15. Moreover, we determined the expression of CD25, CD69 and CD95 antigens on T lymphocytes.Results: The percentage of CD4+/CD3+ T lymphocytes in the controls was higher than in laryngeal cancer patients, both with early and late stages of the disease. The percentage of CD8+/CD3+ T lymphocytes in healthy controls was lower than in patients with early and late clinical stages of laryngeal cancer. Patients with advanced laryngeal cancer showed a lower percentage of iNKT cells and higher frequencies of T regulatory cells (Tregs than the controls. Advanced clinical stages of laryngeal cancer are associated with impaired activation of lymphocytes.Conclusions: Our study confirmed that laryngeal cancer cells exert a strong suppressor effect on the immune system of the host. This is reflected by a decrease in the percentage of iNKT cells that are capable of cancer cell elimination, and a concomitant increase in the percentage of Tregs. However, further studies are needed in order to explain the underlying mechanisms of immunosuppression and understand interactions between immune and cancer cells.

Exploiting immune cell metabolic machinery for functional HIV cure and the prevention of inflammaging.

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Palmer, Clovis S; Palchaudhuri, Riya; Albargy, Hassan; Abdel-Mohsen, Mohamed; Crowe, Suzanne M

2018-01-01

An emerging paradigm in immunology suggests that metabolic reprogramming and immune cell activation and functions are intricately linked. Viral infections, such as HIV infection, as well as cancer force immune cells to undergo major metabolic challenges. Cells must divert energy resources in order to mount an effective immune response. However, the fact that immune cells adopt specific metabolic programs to provide host defense against intracellular pathogens and how this metabolic shift impacts immune cell functions and the natural course of diseases have only recently been appreciated. A clearer insight into how these processes are inter-related will affect our understanding of several fundamental aspects of HIV persistence. Even in patients with long-term use of anti-retroviral therapies, HIV infection persists and continues to cause chronic immune activation and inflammation, ongoing and cumulative damage to multiple organs systems, and a reduction in life expectancy. HIV-associated fundamental changes to the metabolic machinery of the immune system can promote a state of "inflammaging", a chronic, low-grade inflammation with specific immune changes that characterize aging, and can also contribute to the persistence of HIV in its reservoirs. In this commentary, we will bring into focus evolving concepts on how HIV modulates the metabolic machinery of immune cells in order to persist in reservoirs and how metabolic reprogramming facilitates a chronic state of inflammation that underlies the development of age-related comorbidities. We will discuss how immunometabolism is facilitating the changing paradigms in HIV cure research and outline the novel therapeutic opportunities for preventing inflammaging and premature development of age-related conditions in HIV + individuals.

The major targets of acute norovirus infection are immune cells in the gut-associated lymphoid tissue.

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Grau, Katrina R; Roth, Alexa N; Zhu, Shu; Hernandez, Abel; Colliou, Natacha; DiVita, Bayli B; Philip, Drake T; Riffe, Cara; Giasson, Benoit; Wallet, Shannon M; Mohamadzadeh, Mansour; Karst, Stephanie M

2017-12-01

Noroviruses are the leading cause of food-borne gastroenteritis outbreaks and childhood diarrhoea globally, estimated to be responsible for 200,000 deaths in children each year 1-4 . Thus, reducing norovirus-associated disease is a critical priority. Development of vaccines and therapeutics has been hindered by the limited understanding of basic norovirus pathogenesis and cell tropism. While macrophages, dendritic cells, B cells and stem-cell-derived enteroids can all support infection of certain noroviruses in vitro 5-7 , efforts to define in vivo norovirus cell tropism have generated conflicting results. Some studies detected infected intestinal immune cells 8-12 , other studies detected epithelial cells 13 , and still others detected immune and epithelial cells 14-16 . Major limitations of these studies are that they were performed on tissue sections from immunocompromised or germ-free hosts, chronically infected hosts where the timing of infection was unknown, or following non-biologically relevant inoculation routes. Here, we report that the dominant cellular targets of a murine norovirus inoculated orally into immunocompetent mice are macrophages, dendritic cells, B cells and T cells in the gut-associated lymphoid tissue. Importantly, we also demonstrate that a norovirus can infect T cells, a previously unrecognized target, in vitro. These findings represent the most extensive analyses to date of in vivo norovirus cell tropism in orally inoculated, immunocompetent hosts at the peak of acute infection and thus they significantly advance our basic understanding of norovirus pathogenesis.

Infective Larvae of Brugia malayi Induce Polarization of Host Macrophages that Helps in Immune Evasion

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Aditi Sharma

2018-02-01

Full Text Available Filarial parasites suppress, divert, or polarize the host immune response to aid their survival. However, mechanisms that govern the polarization of host MΦs during early filarial infection are not completely understood. In this study, we infected BALB/c mice with infective larvae stage-3 of Brugia malayi (Bm-L3 and studied their effect on the polarization of splenic MΦs. Results showed that MΦs displayed M2-phenotype by day 3 p.i. characterized by upregulated IL-4, but reduced IL-12 and Prostaglandin-D2 secretion. Increased arginase activity, higher arginase-1 but reduced NOS2 expression and poor phagocytic and antigen processing capacity was also observed. M2 MΦs supported T-cell proliferation and characteristically upregulated p-ERK but downregulated NF-κB-p65 and NF-κB-p50/105. Notably, Bm-L3 synergized with host regulatory T-cells (Tregs and polarized M2 MΦs to regulatory MΦs (Mregs by day 7 p.i., which secreted copious amounts of IL-10 and prostaglandin-E2. Mregs also showed upregulated expression levels of MHC-II, CD80, and CD86 and exhibited increased antigen-processing capacity but displayed impaired activation of NF-κB-p65 and NF-κB-p50/105. Neutralization of Tregs by anti-GITR + anti-CD25 antibodies checked the polarization of M2 MΦs to Mregs, decreased accumulation of regulatory B cells and inflammatory monocytes, and reduced secretion of IL-10, but enhanced IL-4 production and percentages of eosinophils, which led to Bm-L3 killing. In summary, we report hitherto undocumented effects of early Bm-L3 infection on the polarization of splenic MΦs and show how infective larvae deftly utilize the functional plasticity of host MΦs to establish themselves inside the host.

Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome.

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Ryuma Matsubara

Full Text Available The apicomplexan parasite Toxoplasma gondii produces the plant hormone abscisic acid, but it is unclear if phytohormones are produced by the malaria parasite Plasmodium spp., the most important parasite of this phylum. Here, we report detection of salicylic acid, an immune-related phytohormone of land plants, in P. berghei ANKA and T. gondii cell lysates. However, addition of salicylic acid to P. falciparum and T. gondii culture had no effect. We transfected P. falciparum 3D7 with the nahG gene, which encodes a salicylic acid-degrading enzyme isolated from plant-infecting Pseudomonas sp., and established a salicylic acid-deficient mutant. The mutant had a significantly decreased concentration of parasite-synthesized prostaglandin E2, which potentially modulates host immunity as an adaptive evolution of Plasmodium spp. To investigate the function of salicylic acid and prostaglandin E2 on host immunity, we established P. berghei ANKA mutants expressing nahG. C57BL/6 mice infected with nahG transfectants developed enhanced cerebral malaria, as assessed by Evans blue leakage and brain histological observation. The nahG-transfectant also significantly increased the mortality rate of mice. Prostaglandin E2 reduced the brain symptoms by induction of T helper-2 cytokines. As expected, T helper-1 cytokines including interferon-γ and interleukin-2 were significantly elevated by infection with the nahG transfectant. Thus, salicylic acid of Plasmodium spp. may be a new pathogenic factor of this threatening parasite and may modulate immune function via parasite-produced prostaglandin E2.

Group 3 Innate Lymphoid Cells: Communications Hubs of the Intestinal Immune System

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David R. Withers

2017-10-01

Full Text Available The maintenance of mammalian health requires the generation of appropriate immune responses against a broad range of environmental and microbial challenges, which are continually encountered at barrier tissue sites including the skin, lung, and gastrointestinal tract. Dysregulated barrier immune responses result in inflammation, both locally and systemically in peripheral organs. Group 3 innate lymphoid cells (ILC3 are constitutively present at barrier sites and appear to be highly specialized in their ability to sense a range of environmental and host-derived signals. Under homeostatic conditions, ILC3 respond to local cues to maintain tissue homeostasis and restrict inflammatory responses. In contrast, perturbations in the tissue microenvironment resulting from disease, infection, or tissue damage can drive dysregulated pro-inflammatory ILC3 responses and contribute to immunopathology. The tone of the ILC3 response is dictated by a balance of “exogenous” signals, such as dietary metabolites and commensal microbes, and “endogenous” host-derived signals from stromal cells, immune cells, and the nervous system. ILC3 must therefore have the capacity to simultaneously integrate a wide array of complex and dynamic inputs in order to regulate barrier function and tissue health. In this review, we discuss the concept of ILC3 as a “communications hub” in the intestinal tract and associated lymphoid tissues and address the variety of signals, derived from multiple biological systems, which are interpreted by ILC3 to modulate the release of downstream effector molecules and regulate cell–cell crosstalk. Successful integration of environmental cues by ILC3 and downstream propagation to the broader immune system is required to maintain a tolerogenic and anti-inflammatory tone and reinforce barrier function, whereas dysregulation of ILC3 responses can contribute to the onset or progression of clinically relevant chronic inflammatory diseases.

Group 3 Innate Lymphoid Cells: Communications Hubs of the Intestinal Immune System

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Withers, David R.; Hepworth, Matthew R.

2017-01-01

The maintenance of mammalian health requires the generation of appropriate immune responses against a broad range of environmental and microbial challenges, which are continually encountered at barrier tissue sites including the skin, lung, and gastrointestinal tract. Dysregulated barrier immune responses result in inflammation, both locally and systemically in peripheral organs. Group 3 innate lymphoid cells (ILC3) are constitutively present at barrier sites and appear to be highly specialized in their ability to sense a range of environmental and host-derived signals. Under homeostatic conditions, ILC3 respond to local cues to maintain tissue homeostasis and restrict inflammatory responses. In contrast, perturbations in the tissue microenvironment resulting from disease, infection, or tissue damage can drive dysregulated pro-inflammatory ILC3 responses and contribute to immunopathology. The tone of the ILC3 response is dictated by a balance of “exogenous” signals, such as dietary metabolites and commensal microbes, and “endogenous” host-derived signals from stromal cells, immune cells, and the nervous system. ILC3 must therefore have the capacity to simultaneously integrate a wide array of complex and dynamic inputs in order to regulate barrier function and tissue health. In this review, we discuss the concept of ILC3 as a “communications hub” in the intestinal tract and associated lymphoid tissues and address the variety of signals, derived from multiple biological systems, which are interpreted by ILC3 to modulate the release of downstream effector molecules and regulate cell–cell crosstalk. Successful integration of environmental cues by ILC3 and downstream propagation to the broader immune system is required to maintain a tolerogenic and anti-inflammatory tone and reinforce barrier function, whereas dysregulation of ILC3 responses can contribute to the onset or progression of clinically relevant chronic inflammatory diseases. PMID:29085366

Recombinant Listeria monocytogenes as a Live Vaccine Vehicle for the Induction of Protective Anti-Viral Cell-Mediated Immunity

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Shen, Hao; Slifka, Mark K.; Matloubian, Mehrdad; Jensen, Eric R.; Ahmed, Rafi; Miller, Jeff F.

1995-04-01

Listeria monocytogenes (LM) is a Gram-positive bacterium that is able to enter host cells, escape from the endocytic vesicle, multiply within the cytoplasm, and spread directly from cell to cell without encountering the extracellular milieu. The ability of LM to gain access to the host cell cytosol allows proteins secreted by the bacterium to efficiently enter the pathway for major histocompatibility complex class I antigen processing and presentation. We have established a genetic system for expression and secretion of foreign antigens by recombinant strains, based on stable site-specific integration of expression cassettes into the LM genome. The ability of LM recombinants to induce protective immunity against a heterologous pathogen was demonstrated with lymphocytic choriomeningitis virus (LCMV). LM strains expressing the entire LCMV nucleoprotein or an H-2L^d-restricted nucleoprotein epitope (aa 118-126) were constructed. Immunization of mice with LM vaccine strains conferred protection against challenge with virulent strains of LCMV that otherwise establish chronic infection in naive adult mice. In vivo depletion of CD8^+ T cells from vaccinated mice abrogated their ability to clear viral infection, showing that protective anti-viral immunity was due to CD8^+ T cells.

Memory CD8+ T Cells: Orchestrators and Key Players of Innate Immunity?

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Grégoire Lauvau

2016-09-01

Full Text Available Over the past decades, the dichotomy between innate and adaptive immune responses has largely dominated our understanding of immunology. Upon primary encounter with microbial pathogens, differentiation of adaptive immune cells into functional effectors usually takes several days or even longer, making them contribute to host protection only late during primary infection. However, once generated, antigen-experienced T lymphocytes can persist in the organism and constitute a pool of memory cells that mediate fast and effective protection to a recall infection with the same microbial pathogen. Herein, we challenge this classical paradigm by highlighting the "innate nature" of memory CD8+ T cells. First, within the thymus or in the periphery, naïve CD8+ T cells may acquire phenotypic and functional characteristics of memory CD8+ T cells independently of challenge with foreign antigens. Second, both the "unconventional" and the "conventional" memory cells can rapidly express protective effector functions in response to sets of inflammatory cytokines and chemokines signals, independent of cognate antigen triggering. Third, memory CD8+ T cells can act by orchestrating the recruitment, activation, and licensing of innate cells, leading to broad antimicrobial states. Thus, collectively, memory CD8+ T cells may represent important actors of innate immune defenses.

Immune Cell-Supplemented Human Skin Model for Studying Fungal Infections.

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Kühbacher, Andreas; Sohn, Kai; Burger-Kentischer, Anke; Rupp, Steffen

2017-01-01

Human skin is a niche for various fungal species which either colonize the surface of this tissue as commensals or, primarily under conditions of immunosuppression, invade the skin and cause infection. Here we present a method for generation of a human in vitro skin model supplemented with immune cells of choice. This model represents a complex yet amenable tool to study molecular mechanisms of host-fungi interactions at human skin.

Effect of L-arginine on the growth of Plasmodium falciparum and immune modulation of host cells.

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Awasthi, Vikky; Chauhan, Rubika; Chattopadhyay, Debprasad; Das, Jyoti

2017-01-01

Malaria is a life-threatening disease caused by Plasmodium parasites. The life-cycle of Plasmodium species involves several stages both in mosquito and the vertebrate host. In the erythrocytic stage, Plasmodium resides inside the red blood cells (RBCs), where it meets most of its nutritional requirement by degrad- ing host's haemoglobin. L-arginine is required for growth and division of cells. The present study was aimed to demonstrate the effect of supplementation of different concentrations of L-arginine and L-citrulline on the growth of parasite, and effect of the culture supernatant on the host's peripheral blood mononuclear cells (PBMCs). To examine the effect of supplementation of L-arginine and L-citrulline, Plasmodium falciparum (3D7 strain) was cultured in RPMI 1640, L-arginine deficient RPMI 1640, and in different concentrations of L-arginine, and L-citrulline supplemented in arginine deficient RPMI 1640 medium. To have a holistic view of in vivo cell activation, the PBMCs isolated from healthy human host were cultured in the supernatant collected from P. falciparum culture. Growth of the parasite was greatly enhanced in L-arginine supplemented media and was found to be concentration dependent. However, parasite growth was compromised in L-citrulline supplemented and L-arginine deficient media. The supernatant collected from L-arginine supplemented parasite media (sArg) showed increased FOXP3 and interleukin-10 (IL-10) expression as compared to the supernatant collected from L-citrulline supple- mented parasite media (sCit). The in vitro culture results showed, decreased parasite growth, and decreased expression of programmed cell death-1 (PD-1) (a coinhibitory molecule) and IL-10 in the L-citrulline supplemented media as compared to L-arginine supplemented media. Hence, it was concluded that L-citrulline supplementation would be a better alternative than L-arginine to inhibit the parasite growth.

Vaccination with an Attenuated Mutant of Ehrlichia chaffeensis Induces Pathogen-Specific CD4+ T Cell Immunity and Protection from Tick-Transmitted Wild-Type Challenge in the Canine Host.

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Jodi L McGill

Full Text Available Ehrlichia chaffeensis is a tick-borne rickettsial pathogen and the causative agent of human monocytic ehrlichiosis. Transmitted by the Amblyomma americanum tick, E. chaffeensis also causes disease in several other vertebrate species including white-tailed deer and dogs. We have recently described the generation of an attenuated mutant strain of E. chaffeensis, with a mutation in the Ech_0660 gene, which is able to confer protection from secondary, intravenous-administered, wild-type E. chaffeensis infection in dogs. Here, we extend our previous results, demonstrating that vaccination with the Ech_0660 mutant protects dogs from physiologic, tick-transmitted, secondary challenge with wild-type E. chaffeensis; and describing, for the first time, the cellular and humoral immune responses induced by Ech_0660 mutant vaccination and wild-type E. chaffeensis infection in the canine host. Both vaccination and infection induced a rise in E. chaffeensis-specific antibody titers and a significant Th1 response in peripheral blood as measured by E. chaffeensis antigen-dependent CD4+ T cell proliferation and IFNγ production. Further, we describe for the first time significant IL-17 production by peripheral blood leukocytes from both Ech_0660 mutant vaccinated animals and control animals infected with wild-type E. chaffeensis, suggesting a previously unrecognized role for IL-17 and Th17 cells in the immune response to rickettsial pathogens. Our results are a critical first step towards defining the role of the immune system in vaccine-induced protection from E. chaffeensis infection in an incidental host; and confirm the potential of the attenuated mutant clone, Ech_0660, to be used as a vaccine candidate for protection against tick-transmitted E. chaffeensis infection.

Host translational inhibition by Pseudomonas aeruginosa Exotoxin A Triggers an immune response in Caenorhabditis elegans.

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McEwan, Deborah L; Kirienko, Natalia V; Ausubel, Frederick M

2012-04-19

Intestinal epithelial cells are exposed to both innocuous and pathogenic microbes, which need to be distinguished to mount an effective immune response. To understand the mechanisms underlying pathogen recognition, we investigated how Pseudomonas aeruginosa triggers intestinal innate immunity in Caenorhabditis elegans, a process independent of Toll-like pattern recognition receptors. We show that the P. aeruginosa translational inhibitor Exotoxin A (ToxA), which ribosylates elongation factor 2 (EF2), upregulates a significant subset of genes normally induced by P. aeruginosa. Moreover, immune pathways involving the ATF-7 and ZIP-2 transcription factors, which protect C. elegans from P. aeruginosa, are required for preventing ToxA-mediated lethality. ToxA-responsive genes are not induced by enzymatically inactive ToxA protein but can be upregulated independently of ToxA by disruption of host protein translation. Thus, C. elegans has a surveillance mechanism to recognize ToxA through its effect on protein translation rather than by direct recognition of either ToxA or ribosylated EF2. Copyright © 2012 Elsevier Inc. All rights reserved.

Immune regulation by microbiome metabolites.

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Kim, Chang H

2018-03-22

Commensal microbes and the host immune system have been co-evolved for mutual regulation. Microbes regulate the host immune system, in part, by producing metabolites. A mounting body of evidence indicates that diverse microbial metabolites profoundly regulate the immune system via host receptors and other target molecules. Immune cells express metabolite-specific receptors such as P2X 7 , GPR41, GPR43, GPR109A, aryl hydrocarbon receptor precursor (AhR), pregnane X receptor (PXR), farnesoid X receptor (FXR), TGR5 and other molecular targets. Microbial metabolites and their receptors form an extensive array of signals to respond to changes in nutrition, health and immunological status. As a consequence, microbial metabolite signals contribute to nutrient harvest from diet, and regulate host metabolism and the immune system. Importantly, microbial metabolites bidirectionally function to promote both tolerance and immunity to effectively fight infection without developing inflammatory diseases. In pathogenic conditions, adverse effects of microbial metabolites have been observed as well. Key immune-regulatory functions of the metabolites, generated from carbohydrates, proteins and bile acids, are reviewed in this article. © 2018 John Wiley & Sons Ltd.

Granzyme A Is Required for Regulatory T-Cell Mediated Prevention of Gastrointestinal Graft-versus-Host Disease.

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Sarvari Velaga

Full Text Available In our previous work we could identify defects in human regulatory T cells (Tregs likely favoring the development of graft-versus-host disease (GvHD following allogeneic stem cell transplantation (SCT. Treg transcriptome analyses comparing GvHD and immune tolerant patients uncovered regulated gene transcripts highly relevant for Treg cell function. Moreover, granzyme A (GZMA also showed a significant lower expression at the protein level in Tregs of GvHD patients. GZMA induces cytolysis in a perforin-dependent, FAS-FASL independent manner and represents a cell-contact dependent mechanism for Tregs to control immune responses. We therefore analyzed the functional role of GZMA in a murine standard model for GvHD. For this purpose, adoptively transferred CD4+CD25+ Tregs from gzmA-/- mice were analyzed in comparison to their wild type counterparts for their capability to prevent murine GvHD. GzmA-/- Tregs home efficiently to secondary lymphoid organs and do not show phenotypic alterations with respect to activation and migration properties to inflammatory sites. Whereas gzmA-/- Tregs are highly suppressive in vitro, Tregs require GZMA to rescue hosts from murine GvHD, especially regarding gastrointestinal target organ damage. We herewith identify GZMA as critical effector molecule of human Treg function for gastrointestinal immune response in an experimental GvHD model.

Rationale for immune-based therapies in Merkel polyomavirus-positive and -negative Merkel cell carcinomas.

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Vandeven, Natalie; Nghiem, Paul

2016-07-01

Merkel cell carcinoma (MCC) is a rare but often deadly skin cancer that is typically caused by the Merkel cell polyomavirus (MCPyV). Polyomavirus T-antigen oncoproteins are persistently expressed in virus-positive MCCs (˜80% of cases), while remarkably high numbers of tumor-associated neoantigens are detected in virus-negative MCCs, suggesting that both MCC subsets may be immunogenic. Here we review mechanisms by which these immunogenic tumors evade multiple levels of host immunity. Additionally, we summarize the exciting potential of diverse immune-based approaches to treat MCC. In particular, agents blocking the PD-1 axis have yielded strikingly high response rates in MCC as compared with other solid tumors, highlighting the potential for immune-mediated treatment of this disease.

Immunity to fish rhabdoviruses

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Purcell, Maureen K.; Laing, Kerry J.; Winton, James R.

2012-01-01

Members of the family Rhabdoviridae are single-stranded RNA viruses and globally important pathogens of wild and cultured fish and thus relatively well studied in their respective hosts or other model systems. Here, we review the protective immune mechanisms that fish mount in response to rhabdovirus infections. Teleost fish possess the principal components of innate and adaptive immunity found in other vertebrates. Neutralizing antibodies are critical for long-term protection from fish rhabdoviruses, but several studies also indicate a role for cell-mediated immunity. Survival of acute rhabdoviral infection is also dependent on innate immunity, particularly the interferon (IFN) system that is rapidly induced in response to infection. Paradoxically, rhabdoviruses are sensitive to the effects of IFN but virulent rhabdoviruses can continue to replicate owing to the abilities of the matrix (M) protein to mediate host-cell shutoff and the non-virion (NV) protein to subvert programmed cell death and suppress functional IFN. While many basic features of the fish immune response to rhabdovirus infections are becoming better understood, much less is known about how factors in the environment affect the ecology of rhabdovirus infections in natural populations of aquatic animals.

Immunity to fish rhabdoviruses.

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Purcell, Maureen K; Laing, Kerry J; Winton, James R

2012-01-01

Members of the family Rhabdoviridae are single-stranded RNA viruses and globally important pathogens of wild and cultured fish and thus relatively well studied in their respective hosts or other model systems. Here, we review the protective immune mechanisms that fish mount in response to rhabdovirus infections. Teleost fish possess the principal components of innate and adaptive immunity found in other vertebrates. Neutralizing antibodies are critical for long-term protection from fish rhabdoviruses, but several studies also indicate a role for cell-mediated immunity. Survival of acute rhabdoviral infection is also dependent on innate immunity, particularly the interferon (IFN) system that is rapidly induced in response to infection. Paradoxically, rhabdoviruses are sensitive to the effects of IFN but virulent rhabdoviruses can continue to replicate owing to the abilities of the matrix (M) protein to mediate host-cell shutoff and the non‑virion (NV) protein to subvert programmed cell death and suppress functional IFN. While many basic features of the fish immune response to rhabdovirus infections are becoming better understood, much less is known about how factors in the environment affect the ecology of rhabdovirus infections in natural populations of aquatic animals.

Immunity to Fish Rhabdoviruses

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Maureen K. Purcell

2012-01-01

Full Text Available Members of the family Rhabdoviridae are single-stranded RNA viruses and globally important pathogens of wild and cultured fish and thus relatively well studied in their respective hosts or other model systems. Here, we review the protective immune mechanisms that fish mount in response to rhabdovirus infections. Teleost fish possess the principal components of innate and adaptive immunity found in other vertebrates. Neutralizing antibodies are critical for long-term protection from fish rhabdoviruses, but several studies also indicate a role for cell-mediated immunity. Survival of acute rhabdoviral infection is also dependent on innate immunity, particularly the interferon (IFN system that is rapidly induced in response to infection. Paradoxically, rhabdoviruses are sensitive to the effects of IFN but virulent rhabdoviruses can continue to replicate owing to the abilities of the matrix (M protein to mediate host-cell shutoff and the non‑virion (NV protein to subvert programmed cell death and suppress functional IFN. While many basic features of the fish immune response to rhabdovirus infections are becoming better understood, much less is known about how factors in the environment affect the ecology of rhabdovirus infections in natural populations of aquatic animals.

Use of an Optical Trap for Study of Host-Pathogen Interactions for Dynamic Live Cell Imaging

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Tam, Jenny M.; Castro, Carlos E.; Heath, Robert J. W.; Mansour, Michael K.; Cardenas, Michael L.; Xavier, Ramnik J.; Lang, Matthew J.; Vyas, Jatin M.

2011-01-01

Dynamic live cell imaging allows direct visualization of real-time interactions between cells of the immune system1, 2; however, the lack of spatial and temporal control between the phagocytic cell and microbe has rendered focused observations into the initial interactions of host response to pathogens difficult. Historically, intercellular contact events such as phagocytosis3 have been imaged by mixing two cell types, and then continuously scanning the field-of-view to find serendipitous int...

Neurofibromin 1 Impairs Natural Killer T-Cell-Dependent Antitumor Immunity against a T-Cell Lymphoma

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Jianyun Liu

2018-01-01

Full Text Available Neurofibromin 1 (NF1 is a tumor suppressor gene encoding a Ras GTPase that negatively regulates Ras signaling pathways. Mutations in NF1 are linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. In terms of antitumor immunity, CD1d-dependent natural killer T (NKT cells play an important role in the innate antitumor immune response. Generally, Type-I NKT cells protect (and Type-II NKT cells impair host antitumor immunity. We have previously shown that CD1d-mediated antigen presentation to NKT cells is regulated by cell signaling pathways. To study whether a haploinsufficiency in NF1 would affect CD1d-dependent activation of NKT cells, we analyzed the NKT-cell population as well as the functional expression of CD1d in Nf1+/− mice. Nf1+/− mice were found to have similar levels of NKT cells as wildtype (WT littermates. Interestingly, however, reduced CD1d expression was observed in Nf1+/− mice compared with their WT littermates. When inoculated with a T-cell lymphoma in vivo, Nf1+/− mice survived longer than their WT littermates. Furthermore, blocking CD1d in vivo significantly enhanced antitumor activity in WT, but not in Nf1+/− mice. In contrast, a deficiency in Type-I NKT cells increased antitumor activity in Nf1+/− mice, but not in WT littermates. Therefore, these data suggest that normal NF1 expression impairs CD1d-mediated NKT-cell activation and antitumor activity against a T-cell lymphoma.

Dual analysis of the murine cytomegalovirus and host cell transcriptomes reveal new aspects of the virus-host cell interface.

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Vanda Juranic Lisnic

Full Text Available Major gaps in our knowledge of pathogen genes and how these gene products interact with host gene products to cause disease represent a major obstacle to progress in vaccine and antiviral drug development for the herpesviruses. To begin to bridge these gaps, we conducted a dual analysis of Murine Cytomegalovirus (MCMV and host cell transcriptomes during lytic infection. We analyzed the MCMV transcriptome during lytic infection using both classical cDNA cloning and sequencing of viral transcripts and next generation sequencing of transcripts (RNA-Seq. We also investigated the host transcriptome using RNA-Seq combined with differential gene expression analysis, biological pathway analysis, and gene ontology analysis. We identify numerous novel spliced and unspliced transcripts of MCMV. Unexpectedly, the most abundantly transcribed viral genes are of unknown function. We found that the most abundant viral transcript, recently identified as a noncoding RNA regulating cellular microRNAs, also codes for a novel protein. To our knowledge, this is the first viral transcript that functions both as a noncoding RNA and an mRNA. We also report that lytic infection elicits a profound cellular response in fibroblasts. Highly upregulated and induced host genes included those involved in inflammation and immunity, but also many unexpected transcription factors and host genes related to development and differentiation. Many top downregulated and repressed genes are associated with functions whose roles in infection are obscure, including host long intergenic noncoding RNAs, antisense RNAs or small nucleolar RNAs. Correspondingly, many differentially expressed genes cluster in biological pathways that may shed new light on cytomegalovirus pathogenesis. Together, these findings provide new insights into the molecular warfare at the virus-host interface and suggest new areas of research to advance the understanding and treatment of cytomegalovirus

Immune reaction and colorectal cancer: friends or foes?

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Formica, Vincenzo; Cereda, Vittore; Nardecchia, Antonella; Tesauro, Manfredi; Roselli, Mario

2014-09-21

The potential clinical impact of enhancing antitumor immunity is increasingly recognized in oncology therapeutics for solid tumors. Colorectal cancer is one of the most studied neoplasms for the tumor-host immunity relationship. Although immune cell populations involved in such a relationship and their prognostic role in colorectal cancer development have clearly been identified, still no approved therapies based on host immunity intensification have so far been introduced in clinical practice. Moreover, a recognized risk in enhancing immune reaction for colitis-associated colorectal cancer development has limited the emphasis of this approach. The aim of the present review is to discuss immune components involved in the host immune reaction against colorectal cancer and analyze the fine balance between pro-tumoral and anti-tumoral effect of immunity in this model of disease.

Cycle Inhibiting Factors (Cifs: Cyclomodulins That Usurp the Ubiquitin-Dependent Degradation Pathway of Host Cells

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Eric Oswald

2011-03-01

Full Text Available Cycle inhibiting factors (Cifs are type III secreted effectors produced by diverse pathogenic bacteria. Cifs are “cyclomodulins” that inhibit the eukaryotic host cell cycle and also hijack other key cellular processes such as those controlling the actin network and apoptosis. This review summarizes current knowledge on Cif since its first characterization in enteropathogenic Escherichia coli, the identification of several xenologues in distant pathogenic bacteria, to its structure elucidation and the recent deciphering of its mode of action. Cif impairs the host ubiquitin proteasome system through deamidation of ubiquitin or the ubiquitin-like protein NEDD8 that regulates Cullin-Ring-ubiquitin Ligase (CRL complexes. The hijacking of the ubiquitin-dependent degradation pathway of host cells results in the modulation of various cellular functions such as epithelium renewal, apoptosis and immune response. Cif is therefore a powerful weapon in the continuous arm race that characterizes host-bacteria interactions.

Tracing Conidial Fate and Measuring Host Cell Antifungal Activity Using a Reporter of Microbial Viability in the Lung

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Anupam Jhingran

2012-12-01

Full Text Available Fluorescence can be harnessed to monitor microbial fate and to investigate functional outcomes of individual microbial cell-host cell encounters at portals of entry in native tissue environments. We illustrate this concept by introducing fluorescent Aspergillus reporter (FLARE conidia that simultaneously report phagocytic uptake and fungal viability during cellular interactions with the murine respiratory innate immune system. Our studies using FLARE conidia reveal stepwise and cell-type-specific requirements for CARD9 and Syk, transducers of C-type lectin receptor and integrin signals, in neutrophil recruitment, conidial uptake, and conidial killing in the lung. By achieving single-event resolution in defined leukocyte populations, the FLARE method enables host cell profiling on the basis of pathogen uptake and killing and may be extended to other pathogens in diverse model host organisms to query molecular, cellular, and pharmacologic mechanisms that shape host-microbe interactions.

Function of endoplasmic reticulum calcium ATPase in innate immunity-mediated programmed cell death

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Zhu, Xiaohong; Caplan, Jeffrey; Mamillapalli, Padmavathi; Czymmek, Kirk; Dinesh-Kumar, Savithramma P

2010-01-01

Programmed cell death (PCD) initiated at the pathogen-infected sites during the plant innate immune response is thought to prevent the development of disease. Here, we describe the identification and characterization of an ER-localized type IIB Ca2+-ATPase (NbCA1) that function as a regulator of PCD. Silencing of NbCA1 accelerates viral immune receptor N- and fungal-immune receptor Cf9-mediated PCD, as well as non-host pathogen Pseudomonas syringae pv. tomato DC3000 and the general elicitor cryptogein-induced cell death. The accelerated PCD rescues loss-of-resistance phenotype of Rar1, HSP90-silenced plants, but not SGT1-silenced plants. Using a genetically encoded calcium sensor, we show that downregulation of NbCA1 results in the modulation of intracellular calcium signalling in response to cryptogein elicitor. We further show that NbCAM1 and NbrbohB function as downstream calcium decoders in N-immune receptor-mediated PCD. Our results indicate that ER-Ca2+-ATPase is a component of the calcium efflux pathway that controls PCD during an innate immune response. PMID:20075858

Immune evasion in ebolavirus infections.

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Audet, Jonathan; Kobinger, Gary P

2015-02-01

Ebola virus (EBOV) infects humans as well as several animal species. It can lead to a highly lethal disease, with mortality rates approaching 90% in primates. Recent advances have deepened our understanding of how this virus is able to prevent the development of protective immune responses. The EBOV genome encodes eight proteins, four of which were shown to interact with the host in ways that counteract the immune response. The viral protein 35 (VP35) is capable of capping dsRNA and interacts with IRF7 to prevent detection of the virus by immune cells. The main role of the soluble glycoprotein (sGP) is still unclear, but it is capable of subverting the anti-GP1,2 antibody response. The GP1,2 protein has shown anti-tetherin activity and the ability to hide cell-surface proteins. Finally, VP24 interferes with the production of interferons (IFNs) and with IFN signaling in infected cells. Taken together, these data point to extensive adaptation of EBOV to evade the immune system of dead end hosts. While our understanding of the interactions between the human and viral proteins increases, details of those interactions in other hosts remain largely unclear and represent a gap in our knowledge.

Characterization and monitoring of host immune responses to infectious agents: what a future for microbiological diagnostics?

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Riccardo Dolcetti

2009-06-01

Full Text Available Our knowledge on the mechanisms underlying microbial pathogenesis and host-microbe interactions has greatly improved over the last decade. In particular, the development of new and specific analytical methods has allowed the detailed characterization of innate and adaptive immune responses against clinically relevant microbial infections. Immunogenetic studies are continuously providing new insights on the genetic bases of individual differences in susceptibility to specific pathogens and most of the genetic markers identified so far include polymorphisms in genes controlling both innate and adaptive immune responses. Moreover, new standardized T cell assays allow reliable and reproducible evaluations of T cell phenotype and functions (i.e.: ELISPOT, including the identification of distinct functional signatures that are associated with the control of the infection.Although the number of these assays currently used in clinical practice is limited, a considerable increase is foreseen for the near future.This perspective constitutes an unprecedented opportunity for Clinical Microbiologists, who may now develop and apply integrated microbiologic/immunologic assays that may be useful for a more precise diagnostic definition and a more accurate clinical monitoring of the disease.

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells.

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Wunsch, Christopher M; Lewis, Janina P

2015-12-17

Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior. However, ensuring that the anaerobic bacteria are live during experimental investigation of the events may pose challenges. Porphyromonas gingivalis, a Gram-negative anaerobe, is capable of invading a variety of eukaryotic non-phagocytic cells. This article outlines how to successfully culture and assess the ability of P. gingivalis to invade human umbilical vein endothelial cells (HUVECs). Two protocols were developed: one to measure bacteria that can successfully invade and survive within the host, and the other to visualize bacteria interacting with host cells. These techniques necessitate the use of an anaerobic chamber to supply P. gingivalis with an anaerobic environment for optimal growth. The first protocol is based on the antibiotic protection assay, which is largely used to study the invasion of host cells by bacteria. However, the antibiotic protection assay is limited; only intracellular bacteria that are culturable following antibiotic treatment and host cell lysis are measured. To assess all bacteria interacting with host cells, both live and dead, we developed a protocol that uses fluorescent microscopy to examine host-pathogen interaction. Bacteria are fluorescently labeled with 2',7'-Bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and used to infect eukaryotic cells under anaerobic conditions. Following fixing with paraformaldehyde and permeabilization with 0.2% Triton X-100, host cells are labeled with TRITC phalloidin and DAPI to label the cell cytoskeleton and nucleus, respectively. Multiple images taken at different focal points (Z-stack) are obtained for temporal

The Host Immune Response to Streptococcus pneumoniae: Bridging Innate and Adaptive Immunity

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2006-07-06

P.J. (1989) Effect of Streptococcus pneumoniae on human respiratory epithelium in vitro. Infect. Immun. 57: 2006-2013. Stoop, J.N., van der Molen ...antibiotics. Clin. Microbiol. Rev. 3: 171-196. Knapp, S., Wieland, C.W., van ’t Veer, C., Takeuchi, O., Akira, S., Florquin, S., and van der Poll...R.G., Baan, C.C., van der Laan, L.J., Kuipers, E.J., Kusters, J.G., and Janssen, H.L. (2005) Regulatory T cells contribute to the impaired immune

Experimentally-induced immune activation in natural hosts of SIV induces significant increases in viral replication and CD4+ T cell depletion

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Ribeiro, Ruy M [Los Alamos National Laboratory

2008-01-01

Chronically SIVagm-infected African green monkeys (AGMs) have a remarkably stable non-pathogenic disease course, with levels of immune activation in chronic SIVagm infection similar to those observed in uninfected monkeys and stable viral loads (VLs) for long periods of time. In vivo administration of lipopolysaccharide (LPS) or an IL-2/diphtheria toxin fusion protein (Ontak) to chronically SIVagm-infected AGMs triggered increases in immune activation and subsequently of viral replication and depletion of intestinal CD4{sup +} T cells. Our study indicates that circulating microbial products can increase viral replication by inducing immune activation and increasing the number of viral target cells, thus demonstrating that immune activation and T cell prolifeation are key factors in AIDS pathogenesis.

Interaction Between 2 Nutraceutical Treatments and Host Immune Status in the Pediatric Critical Illness Stress-Induced Immune Suppression Comparative Effectiveness Trial.

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Carcillo, Joseph A; Dean, J Michael; Holubkov, Richard; Berger, John; Meert, Kathleen L; Anand, Kanwaljeet J S; Zimmerman, Jerry J; Newth, Christopher J L; Harrison, Rick; Burr, Jeri; Willson, Douglas F; Nicholson, Carol; Bell, Michael J; Berg, Robert A; Shanley, Thomas P; Heidemann, Sabrina M; Dalton, Heidi; Jenkins, Tammara L; Doctor, Allan; Webster, Angie; Tamburro, Robert F

2017-11-01

The pediatric Critical Illness Stress-induced Immune Suppression (CRISIS) trial compared the effectiveness of 2 nutraceutical supplementation strategies and found no difference in the development of nosocomial infection and sepsis in the overall population. We performed an exploratory post hoc analysis of interaction between nutraceutical treatments and host immune status related to the development of nosocomial infection/sepsis. Children from the CRISIS trial were analyzed according to 3 admission immune status categories marked by decreasing immune competence: immune competent without lymphopenia, immune competent with lymphopenia, and previously immunocompromised. The comparative effectiveness of the 2 treatments was analyzed for interaction with immune status category. There were 134 immune-competent children without lymphopenia, 79 previously immune-competent children with lymphopenia, and 27 immunocompromised children who received 1 of the 2 treatments. A significant interaction was found between treatment arms and immune status on the time to development of nosocomial infection and sepsis ( P patient characteristic.

A novel monoclonal anti-CD81 antibody produced by genetic immunization efficiently inhibits Hepatitis C virus cell-cell transmission.

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Isabel Fofana

Full Text Available Hepatitis C virus (HCV infection is a challenge to prevent and treat because of the rapid development of drug resistance and escape. Viral entry is required for initiation, spread, and maintenance of infection, making it an attractive target for antiviral strategies.Using genetic immunization, we produced four monoclonal antibodies (mAbs against the HCV host entry factor CD81. The effects of antibodies on inhibition of HCV infection and dissemination were analyzed in HCV permissive human liver cell lines.The anti-CD81 mAbs efficiently inhibited infection by HCV of different genotypes as well as a HCV escape variant selected during liver transplantation and re-infecting the liver graft. Kinetic studies indicated that anti-CD81 mAbs target a post-binding step during HCV entry. In addition to inhibiting cell-free HCV infection, one antibody was also able to block neutralizing antibody-resistant HCV cell-cell transmission and viral dissemination without displaying any detectable toxicity.A novel anti-CD81 mAb generated by genetic immunization efficiently blocks HCV spread and dissemination. This antibody will be useful to further unravel the role of virus-host interactions during HCV entry and cell-cell transmission. Furthermore, this antibody may be of interest for the development of antivirals for prevention and treatment of HCV infection.

Feast or famine: the host-pathogen battle over amino acids.

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Zhang, Yanjia J; Rubin, Eric J

2013-07-01

Intracellular bacterial pathogens often rely on their hosts for essential nutrients. Host cells, in turn, attempt to limit nutrient availability, using starvation as a mechanism of innate immunity. Here we discuss both host mechanisms of amino acid starvation and the diverse adaptations of pathogens to their nutrient-deprived environments. These processes provide both key insights into immune subversion and new targets for drug development. © 2013 John Wiley & Sons Ltd.

The Role of MicroRNAs in Myeloid Cells during Graft-versus-Host Disease

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Sophia Chen

2018-01-01

Full Text Available The successful treatment of various hematologic diseases with allogeneic hematopoietic cell transplantation is often limited by the occurrence of graft-versus-host disease (GvHD. Several microRNAs (miRs have recently been shown to impact the biology of GvHD by regulating pro- as well as anti-inflammatory target genes. There is increasing evidence that a single miR can have different effects by preferentially targeting certain genes depending on the cell type that the miR is analyzed in. This review will focus on the role of miRs in myeloid cells during the development of acute and chronic GvHD and autoimmune diseases. Because miRs act on the expression of multiple target genes and may thereby influence the immune system at different functional levels, they are potentially attractive targets for the modification of allogeneic immune responses using miR mimics and inhibitors.

Identification of bovine leukemia virus tax function associated with host cell transcription, signaling, stress response and immune response pathway by microarray-based gene expression analysis

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Arainga Mariluz

2012-03-01

Full Text Available Abstract Background Bovine leukemia virus (BLV is associated with enzootic bovine leukosis and is closely related to human T-cell leukemia virus type I. The Tax protein of BLV is a transcriptional activator of viral replication and a key contributor to oncogenic potential. We previously identified interesting mutant forms of Tax with elevated (TaxD247G or reduced (TaxS240P transactivation effects on BLV replication and propagation. However, the effects of these mutations on functions other than transcriptional activation are unknown. In this study, to identify genes that play a role in the cascade of signal events regulated by wild-type and mutant Tax proteins, we used a large-scale host cell gene-profiling approach. Results Using a microarray containing approximately 18,400 human mRNA transcripts, we found several alterations after the expression of Tax proteins in genes involved in many cellular functions such as transcription, signal transduction, cell growth, apoptosis, stress response, and immune response, indicating that Tax protein has multiple biological effects on various cellular environments. We also found that TaxD247G strongly regulated more genes involved in transcription, signal transduction, and cell growth functions, contrary to TaxS240P, which regulated fewer genes. In addition, the expression of genes related to stress response significantly increased in the presence of TaxS240P as compared to wild-type Tax and TaxD247G. By contrast, the largest group of downregulated genes was related to immune response, and the majority of these genes belonged to the interferon family. However, no significant difference in the expression level of downregulated genes was observed among the Tax proteins. Finally, the expression of important cellular factors obtained from the human microarray results were validated at the RNA and protein levels by real-time quantitative reverse transcription-polymerase chain reaction and western blotting

Platelets subvert T cell immunity against cancer via GARP-TGFβ axis.

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Rachidi, Saleh; Metelli, Alessandra; Riesenberg, Brian; Wu, Bill X; Nelson, Michelle H; Wallace, Caroline; Paulos, Chrystal M; Rubinstein, Mark P; Garrett-Mayer, Elizabeth; Hennig, Mirko; Bearden, Daniel W; Yang, Yi; Liu, Bei; Li, Zihai

2017-05-05

Cancer-associated thrombocytosis has long been linked to poor clinical outcome, but the underlying mechanism is enigmatic. We hypothesized that platelets promote malignancy and resistance to therapy by dampening host immunity. We show that genetic targeting of platelets enhances adoptive T cell therapy of cancer. An unbiased biochemical and structural biology approach established transforming growth factor β (TGFβ) and lactate as major platelet-derived soluble factors to obliterate CD4 + and CD8 + T cell functions. Moreover, we found that platelets are the dominant source of functional TGFβ systemically as well as in the tumor microenvironment through constitutive expression of the TGFβ-docking receptor glycoprotein A repetitions predominant (GARP) rather than secretion of TGFβ per se. Platelet-specific deletion of the GARP-encoding gene Lrrc32 blunted TGFβ activity at the tumor site and potentiated protective immunity against both melanoma and colon cancer. Last, this study shows that T cell therapy of cancer can be substantially improved by concurrent treatment with readily available antiplatelet agents. We conclude that platelets constrain T cell immunity through a GARP-TGFβ axis and suggest a combination of immunotherapy and platelet inhibitors as a therapeutic strategy against cancer. Copyright © 2017, American Association for the Advancement of Science.

Host immunity in the protective response to vaccination with heat-killed Burkholderia mallei

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Paessler Slobodan

2008-09-01

Full Text Available Abstract Background We performed initial cell, cytokine and complement depletion studies to investigate the possible role of these effectors in response to vaccination with heat-killed Burkholderia mallei in a susceptible BALB/c mouse model of infection. Results While protection with heat-killed bacilli did not result in sterilizing immunity, limited protection was afforded against an otherwise lethal infection and provided insight into potential host protective mechanisms. Our results demonstrated that mice depleted of either B cells, TNF-α or IFN-γ exhibited decreased survival rates, indicating a role for these effectors in obtaining partial protection from a lethal challenge by the intraperitoneal route. Additionally, complement depletion had no effect on immunoglobulin production when compared to non-complement depleted controls infected intranasally. Conclusion The data provide a basis for future studies of protection via vaccination using either subunit or whole-organism vaccine preparations from lethal infection in the experimental BALB/c mouse model. The results of this study demonstrate participation of B220+ cells and pro-inflammatory cytokines IFN-γ and TNF-α in protection following HK vaccination.

Expansion of myeloid immune suppressor Gr+CD11b+ cells in tumor-bearing host directly promotes tumor angiogenesis | Center for Cancer Research

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We demonstrate a novel tumor-promoting role of myeloid immune suppressor Gr+CD11b+ cells, which are evident in cancer patients and tumor-bearing animals. These cells constitute approximately 5% of total cells in tumors. Tumors coinjected with Gr+CD11b+ cells exhibited increased vascular density, vascular maturation, and decreased necrosis. These immune cells produce high

Immune tolerance in radiation chimeras

International Nuclear Information System (INIS)

Awaya, Kazuhiko; Kuniki, Hiromichi; Neki, Miyuki

1978-01-01

Establishment of immune tolerance in radiation chimeras and the mechanism of maintaining it were discussed from certain points. Semiallogeneic radiation chimeras are mostly of long-living, and the hematopoietic organ of this individual consists mainly of the cells derived from the marrow donor, i. e., F 1 -type cells. F 1 -type lymphocytes can distinguish parental strain cells from themselves. In these chimeras, a F 1 -skin graft maintains to be fresh as long as the host is alive, showing immune tolerance effective through its life. In establishment and maintenance of this immune tolerance, the suppressing mechanism of host-type or F 1 -type seems to be involved. The allogeneic radiation chimera has very poor long-survival rate compared with that of the semiallogeneic radiation chimera. To raise this survival rate, efforts are now being made from the immunological point of view. (Ueda, J.)

Immune activation induces immortalization of HTLV-1 LTR-Tax transgenic CD4+ T cells

OpenAIRE

Swaims, Alison Y.; Khani, Francesca; Zhang, Yingyu; Roberts, Arthur I.; Devadas, Satish; Shi, Yufang; Rabson, Arnold B.

2010-01-01

Infection with the human T-cell leukemia virus-1 (HTLV-1) results in a variety of diseases including adult T-cell leukemia/lymphoma (ATL). Although the pathogenesis of these disorders is poorly understood, it involves complex interactions with the host immune system. Activation of infected T cells may play an important role in disease pathogenesis through induction of the oncogenic HTLV-1 Tax transactivator protein. To test this hypothesis, we employed transgenic mice in which Tax is regulate...

Adenylate Cyclases of Trypanosoma brucei, Environmental Sensors and Controllers of Host Innate Immune Response.

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Salmon, Didier

2018-04-25

Trypanosoma brucei , etiological agent of Sleeping Sickness in Africa, is the prototype of African trypanosomes, protozoan extracellular flagellate parasites transmitted by saliva ( Salivaria ). In these parasites the molecular controls of the cell cycle and environmental sensing are elaborate and concentrated at the flagellum. Genomic analyses suggest that these parasites appear to differ considerably from the host in signaling mechanisms, with the exception of receptor-type adenylate cyclases (AC) that are topologically similar to receptor-type guanylate cyclase (GC) of higher eukaryotes but control a new class of cAMP targets of unknown function, the cAMP response proteins (CARPs), rather than the classical protein kinase A cAMP effector (PKA). T. brucei possesses a large polymorphic family of ACs, mainly associated with the flagellar membrane, and these are involved in inhibition of the innate immune response of the host prior to the massive release of immunomodulatory factors at the first peak of parasitemia. Recent evidence suggests that in T. brucei several insect-specific AC isoforms are involved in social motility, whereas only a few AC isoforms are involved in cytokinesis control of bloodstream forms, attesting that a complex signaling pathway is required for environmental sensing. In this review, after a general update on cAMP signaling pathway and the multiple roles of cAMP, I summarize the existing knowledge of the mechanisms by which pathogenic microorganisms modulate cAMP levels to escape immune defense.

Adenylate Cyclases of Trypanosoma brucei, Environmental Sensors and Controllers of Host Innate Immune Response

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Didier Salmon

2018-04-01

Full Text Available Trypanosoma brucei, etiological agent of Sleeping Sickness in Africa, is the prototype of African trypanosomes, protozoan extracellular flagellate parasites transmitted by saliva (Salivaria. In these parasites the molecular controls of the cell cycle and environmental sensing are elaborate and concentrated at the flagellum. Genomic analyses suggest that these parasites appear to differ considerably from the host in signaling mechanisms, with the exception of receptor-type adenylate cyclases (AC that are topologically similar to receptor-type guanylate cyclase (GC of higher eukaryotes but control a new class of cAMP targets of unknown function, the cAMP response proteins (CARPs, rather than the classical protein kinase A cAMP effector (PKA. T. brucei possesses a large polymorphic family of ACs, mainly associated with the flagellar membrane, and these are involved in inhibition of the innate immune response of the host prior to the massive release of immunomodulatory factors at the first peak of parasitemia. Recent evidence suggests that in T. brucei several insect-specific AC isoforms are involved in social motility, whereas only a few AC isoforms are involved in cytokinesis control of bloodstream forms, attesting that a complex signaling pathway is required for environmental sensing. In this review, after a general update on cAMP signaling pathway and the multiple roles of cAMP, I summarize the existing knowledge of the mechanisms by which pathogenic microorganisms modulate cAMP levels to escape immune defense.

Mnn10 Maintains Pathogenicity in Candida albicans by Extending α-1,6-Mannose Backbone to Evade Host Dectin-1 Mediated Antifungal Immunity.

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Shi Qun Zhang

2016-05-01

Full Text Available The cell wall is a dynamic structure that is important for the pathogenicity of Candida albicans. Mannan, which is located in the outermost layer of the cell wall, has been shown to contribute to the pathogenesis of C. albicans, however, the molecular mechanism by which this occurs remains unclear. Here we identified a novel α-1,6-mannosyltransferase encoded by MNN10 in C. albicans. We found that Mnn10 is required for cell wall α-1,6-mannose backbone biosynthesis and polysaccharides organization. Deletion of MNN10 resulted in significant attenuation of the pathogenesis of C. albicans in a murine systemic candidiasis model. Inhibition of α-1,6-mannose backbone extension did not, however, impact the invasive ability of C. albicans in vitro. Notably, mnn10 mutant restored the invasive capacity in athymic nude mice, which further supports the notion of an enhanced host antifungal defense related to this backbone change. Mnn10 mutant induced enhanced Th1 and Th17 cell mediated antifungal immunity, and resulted in enhanced recruitment of neutrophils and monocytes for pathogen clearance in vivo. We also demonstrated that MNN10 could unmask the surface β-(1,3-glucan, a crucial pathogen-associated molecular pattern (PAMP of C. albicans recognized by host Dectin-1. Our results demonstrate that mnn10 mutant could stimulate an enhanced Dectin-1 dependent immune response of macrophages in vitro, including the activation of nuclear factor-κB, mitogen-activated protein kinase pathways, and secretion of specific cytokines such as TNF-α, IL-6, IL-1β and IL-12p40. In summary, our study indicated that α-1,6-mannose backbone is critical for the pathogenesis of C. albicans via shielding β-glucan from recognition by host Dectin-1 mediated immune recognition. Moreover, our work suggests that inhibition of α-1,6-mannose extension by Mnn10 may represent a novel modality to reduce the pathogenicity of C. albicans.

Ebola VP40 in Exosomes Can Cause Immune Cell Dysfunction.

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Pleet, Michelle L; Mathiesen, Allison; DeMarino, Catherine; Akpamagbo, Yao A; Barclay, Robert A; Schwab, Angela; Iordanskiy, Sergey; Sampey, Gavin C; Lepene, Benjamin; Nekhai, Sergei; Aman, M J; Kashanchi, Fatah

2016-01-01

and eventual destruction of the T-cell and myeloid arms of the immune system (bystander lymphocyte apoptosis), allowing the virus to replicate to high titers in the immunocompromised host. Moreover, our results suggest that the use of drugs such as Oxytetracycline to modulate the levels of exosomes exiting EBOV-infected cells may be able to prevent the devastation of the adaptive immune system and allow for an improved rate of survival.

Ebola VP40 in Exosomes Can Cause Immune Cell Dysfunction

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Michelle L. Pleet

2016-11-01

for the deregulation and eventual destruction of the T-cell and myeloid arms of the immune system (bystander lymphocyte apoptosis, allowing the virus to replicate to high titers in the immunocompromised host. Moreover, our results suggest that the use of drugs such as Oxytetracycline to modulate the levels of exosomes exiting EBOV-infected cells may be able to prevent the devastation of the adaptive immune system and allow for an improved rate of survival.

The role of acquired immunity and periodontal disease progression.

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Teng, Yen-Tung A

2003-01-01

Our understanding of the pathogenesis in human periodontal diseases is limited by the lack of specific and sensitive tools or models to study the complex microbial challenges and their interactions with the host's immune system. Recent advances in cellular and molecular biology research have demonstrated the importance of the acquired immune system not only in fighting the virulent periodontal pathogens but also in protecting the host from developing further devastating conditions in periodontal infections. The use of genetic knockout and immunodeficient mouse strains has shown that the acquired immune response-in particular, CD4+ T-cells-plays a pivotal role in controlling the ongoing infection, the immune/inflammatory responses, and the subsequent host's tissue destruction. In particular, studies of the pathogen-specific CD4+ T-cell-mediated immunity have clarified the roles of: (i) the relative diverse immune repertoire involved in periodontal pathogenesis, (ii) the contribution of pathogen-associated Th1-Th2 cytokine expressions in periodontal disease progression, and (iii) micro-organism-triggered periodontal CD4+ T-cell-mediated osteoclastogenic factor, 'RANK-L', which is linked to the induction of alveolar bone destruction in situ. The present review will focus on some recent advances in the acquired immune responses involving B-cells, CD8+ T-cells, and CD4+ T-cells in the context of periodontal disease progression. New approaches will further facilitate our understanding of their underlying molecular mechanisms that may lead to the development of new treatment modalities for periodontal diseases and their associated complications.

Antigen modulation of the immune response. III. Evaluation of the hypothetical short-lived memory cell

International Nuclear Information System (INIS)

Feldbush, T.L.; Lande, I.; Bryan, B.; O'Neill, E.

1974-01-01

The putative short-lived memory cells, whose existence has been suggested by the results of secondary adoptive transfer experiments, were investigated. On the basis of the following evidences we have concluded that the short-lived memory cell is probably an artifact of the adoptive transfer technique: when immune thoracic duct lymphocytes, known to consist predominantly of long-lived memory cells, were transferred to irradiated recipients and challenged at various times after transfer, approximately 80 to 90 percent of the initial response was absent by Day 14 challenge; preirradiating adoptive recipients with increasing dose of x-irradiation tended to lengthen the observed half life of memory cells; single or multiple treatments of immune donors with 0.3 mg Vinblastin before transfer resulted in neither a depression of the initial secondary response nor an alteration in the rate of decline of the memory potential; reconstitution of irradiated hosts with normal spleen cells one day before transfer of memory cells and challenge resulted in inhibition of the adoptive secondary response; and the transfer of memory cells to antigen free intermediate hosts, in which they were allowed to reside for one day or fourteen days before transfer to irradiated recipients, resulted in only a slight decline in their capacity to respond. We propose that the rapid decline of memory potential in adoptive recipients challenged at various times after transfer is due to modulating effects by the hosts as it recovers from irradiation. These effects may be the result of cell crowding or the loss of irradiation-produced stimulatory factors. The relevance of these findings to adoptive transfer systems in general and the secondary response of intact animals is discussed

Regulation of host metabolism and immunity by the gut microbiome

DEFF Research Database (Denmark)

Laursen, Janne Marie

During recent years, central roles of the gut microbiome in metabolic and immunological diseases have been uncovered, and multiple studies have shown that bacterial-derived components shape host physiology and immune responses via direct cellular interactions. The intestinal immune system...... developed a computational framework for identifying bacteria that produce specific endotoxin variants with opposing immunological effects in metagenomic fecal samples. This framework was used to identify the endotoxin variant distribution amongst bacteria in the gut microbiome of Danes and Chinese...... with obesity and type 2 diabetes. We show for the first time that species producing pro-inflammatory endotoxin variants are vastly underrepresented in the gut microbiome compared to species producing non-inflammatory endotoxin and we identify country-specific gram-negative bacterial modules associated...

Nutrition and Helicobacter pylori: Host Diet and Nutritional Immunity Influence Bacterial Virulence and Disease Outcome

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Kathryn P. Haley

2016-01-01

Full Text Available Helicobacter pylori colonizes the stomachs of greater than 50% of the world’s human population making it arguably one of the most successful bacterial pathogens. Chronic H. pylori colonization results in gastritis in nearly all patients; however in a subset of people, persistent infection with H. pylori is associated with an increased risk for more severe disease outcomes including B-cell lymphoma of mucosal-associated lymphoid tissue (MALT lymphoma and invasive adenocarcinoma. Research aimed at elucidating determinants that mediate disease progression has revealed genetic differences in both humans and H. pylori which increase the risk for developing gastric cancer. Furthermore, host diet and nutrition status have been shown to influence H. pylori-associated disease outcomes. In this review we will discuss how H. pylori is able to create a replicative niche within the hostile host environment by subverting and modifying the host-generated immune response as well as successfully competing for limited nutrients such as transition metals by deploying an arsenal of metal acquisition proteins and virulence factors. Lastly, we will discuss how micronutrient availability or alterations in the gastric microbiome may exacerbate negative disease outcomes associated with H. pylori colonization.

The cellular immune response of Daphnia magna under host-parasite genetic variation and variation in initial dose.

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Auld, Stuart K J R; Edel, Kai H; Little, Tom J

2012-10-01

In invertebrate-parasite systems, the likelihood of infection following parasite exposure is often dependent on the specific combination of host and parasite genotypes (termed genetic specificity). Genetic specificity can maintain diversity in host and parasite populations and is a major component of the Red Queen hypothesis. However, invertebrate immune systems are thought to only distinguish between broad classes of parasite. Using a natural host-parasite system with a well-established pattern of genetic specificity, the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa, we found that only hosts from susceptible host-parasite genetic combinations mounted a cellular response following exposure to the parasite. These data are compatible with the hypothesis that genetic specificity is attributable to barrier defenses at the site of infection (the gut), and that the systemic immune response is general, reporting the number of parasite spores entering the hemocoel. Further supporting this, we found that larger cellular responses occurred at higher initial parasite doses. By studying the natural infection route, where parasites must pass barrier defenses before interacting with systemic immune responses, these data shed light on which components of invertebrate defense underlie genetic specificity. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

A computational tool integrating host immunity with antibiotic dynamics to study tuberculosis treatment.

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Pienaar, Elsje; Cilfone, Nicholas A; Lin, Philana Ling; Dartois, Véronique; Mattila, Joshua T; Butler, J Russell; Flynn, JoAnne L; Kirschner, Denise E; Linderman, Jennifer J

2015-02-21

While active tuberculosis (TB) is a treatable disease, many complex factors prevent its global elimination. Part of the difficulty in developing optimal therapies is the large design space of antibiotic doses, regimens and combinations. Computational models that capture the spatial and temporal dynamics of antibiotics at the site of infection can aid in reducing the design space of costly and time-consuming animal pre-clinical and human clinical trials. The site of infection in TB is the granuloma, a collection of immune cells and bacteria that form in the lung, and new data suggest that penetration of drugs throughout granulomas is problematic. Here we integrate our computational model of granuloma formation and function with models for plasma pharmacokinetics, lung tissue pharmacokinetics and pharmacodynamics for two first line anti-TB antibiotics. The integrated model is calibrated to animal data. We make four predictions. First, antibiotics are frequently below effective concentrations inside granulomas, leading to bacterial growth between doses and contributing to the long treatment periods required for TB. Second, antibiotic concentration gradients form within granulomas, with lower concentrations toward their centers. Third, during antibiotic treatment, bacterial subpopulations are similar for INH and RIF treatment: mostly intracellular with extracellular bacteria located in areas non-permissive for replication (hypoxic areas), presenting a slowly increasing target population over time. Finally, we find that on an individual granuloma basis, pre-treatment infection severity (including bacterial burden, host cell activation and host cell death) is predictive of treatment outcome. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA.

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Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

2014-07-01

Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant pathogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantly less virulent on both tomato and Arabidopsis thaliana. Moreover, infiltration of A. thaliana Col-0 leaves with DC3000 ΔaprA evoked a significantly higher level of expression of the defense-related genes FRK1 and PR-1 than did wild-type DC3000. In the flagellin receptor mutant fls2, pathogen virulence and defense-related gene activation did not differ between DC3000 and DC3000 ΔaprA. Together, these results suggest that AprA of DC3000 is important for evasion of recognition by the FLS2 receptor, allowing wild-type DC3000 to be more virulent on its host plant than AprA-deficient DC3000 ΔaprA. To provide further evidence for the role of DC3000 AprA in host immune evasion, we overexpressed the AprA inhibitory peptide AprI of DC3000 in A. thaliana to counteract the immune evasive capacity of DC3000 AprA. Ectopic expression of aprI in A. thaliana resulted in an enhanced level of resistance against wild-type DC3000, while the already elevated level of resistance against DC3000 ΔaprA remained unchanged. Together, these results indicate that evasion of host immunity by the alkaline protease AprA is important for full virulence of strain DC3000 and likely acts by preventing flagellin monomers from being recognized by its cognate immune receptor.

Role of Interleukin-33 in Innate-Type Immune Cells in Allergy

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Susumu Nakae

2013-01-01

Full Text Available Interleukin-33 (IL-33, a member of the IL-1 cytokine family, is preferentially and constitutively expressed in epithelial cells, and it is especially localized in the cells' nucleus. The nuclear IL-33 is released by necrotic cells after tissue injury and/or trauma, and subsequently provokes local inflammation as an alarmin, like high-mobility group box protein-1 (HMGB-1 and IL-1α. IL-33 mainly activates Th2 cells and such innate-type immune cells as mast cells, basophils, eosinophils and natural helper cells that express IL-33R (a heterodimer of IL-1 receptor-like 1 [IL-1RL1; also called ST2, T1, Der4, fit-1] and IL-1 receptor accessory protein [IL-1RAcP]. That activation causes the cells to produce Th2 cytokines, which contribute to host defense against nematodes. On the other hand, excessive and/or inappropriate production of IL-33 is also considered to be involved in the development of such disorders as allergy. In this review, we summarize current knowledge regarding the pathogenic roles of IL-33 in the development of allergic inflammation by focusing on its effects on innate-type immune cells.

Xenopus-FV3 host-pathogen interactions and immune evasion.

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Jacques, Robert; Edholm, Eva-Stina; Jazz, Sanchez; Odalys, Torres-Luquis; Francisco, De Jesús Andino

2017-11-01

We first review fundamental insights into anti-ranavirus immunity learned with the Xenopus laevis/ranavirus FV3 model that are generally applicable to ectothermic vertebrates. We then further investigate FV3 genes involved in immune evasion. Focusing on FV3 knockout (KO) mutants defective for a putative viral caspase activation and recruitment domain-containing (CARD)-like protein (Δ64R-FV3), a β-hydroxysteroid dehydrogenase homolog (Δ52L-FV3), and an immediate-early18kDa protein (FV3-Δ18K), we assessed the involvement of these viral genes in replication, dissemination and interaction with peritoneal macrophages in tadpole and adult frogs. Our results substantiate the role of 64R and 52L as critical immune evasion genes, promoting persistence and dissemination in the host by counteracting type III IFN in tadpoles and type I IFN in adult frogs. Comparably, the substantial accumulation of genome copy numbers and exacerbation of type I and III IFN gene expression responses but deficient release of infectious virus suggests that 18K is a viral regulatory gene. Copyright © 2017 Elsevier Inc. All rights reserved.

Immunoregulatory Effects Triggered by Lactic Acid Bacteria Exopolysaccharides: New Insights into Molecular Interactions with Host Cells

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Jonathan Laiño

2016-08-01

Full Text Available Researchers have demonstrated that lactic acid bacteria (LAB with immunomodulatory capabilities (immunobiotics exert their beneficial effects through several molecules, including cell wall, peptidoglycan, and exopolysaccharides (EPS, that are able to interact with specific host cell receptors. EPS from LAB show a wide heterogeneity in its composition, meaning that biological properties depend on the strain and. therefore, only a part of the mechanism of action has been elucidated for these molecules. In this review, we summarize the current knowledge of the health-promoting actions of EPS from LAB with special focus on their immunoregulatory actions. In addition, we describe our studies using porcine intestinal epithelial cells (PIE cells as a model to evaluate the molecular interactions of EPS from two immunobiotic LAB strains and the host cells. Our studies showed that EPS from immunobiotic LAB have anti-inflammatory capacities in PIE cells since they are able to reduce the production of inflammatory cytokines in cells challenged with the Toll-like receptor (TLR-4-agonist lipopolysaccharide. The effects of EPS were dependent on TLR2, TLR4, and negative regulators of TLR signaling. We also reported that the radioprotective 105 (RP105/MD1 complex, a member of the TLR family, is partially involved in the immunoregulatory effects of the EPS from LAB. Our work described, for the first time, that LAB and their EPS reduce inflammation in intestinal epithelial cells in a RP105/MD1-dependent manner. A continuing challenge for the future is to reveal more effector-receptor relationships in immunobiotic-host interactions that contribute to the beneficial effects of these bacteria on mucosal immune homeostasis. A detailed molecular understanding should lead to a more rational use of immunobiotics in general, and their EPS in particular, as efficient prevention and therapies for specific immune-related disorders in humans and animals.

I-L-C-2 it: type 2 immunity and group 2 innate lymphoid cells in homeostasis.

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von Moltke, Jakob; Locksley, Richard M

2014-12-01

Innate type 2 immune cells are activated in response to helminths, allergens, and certain types of proteases and particulates. Recently, innate type 2 immune pathways have also been implicated in protective host responses to homeostatic perturbations, such as metabolic dysfunction, atherosclerosis, and tissue injury. In this context, innate type 2 cytokines stimulate local tissues, recruit eosinophils, and alternatively activate macrophages to restore homeostasis. As the major source of innate interleukin (IL)-5 and IL-13, group 2 innate lymphoid cells are positioned to initiate and maintain homeostatic type 2 responses. The absence of exogenous stimuli in these processes implicates endogenous pathways in the activation of type 2 immunity and suggests an alternative evolutionary trajectory for type 2 immunity, apart from its role in response to helminths and allergens. Copyright © 2014 Elsevier Ltd. All rights reserved.

The role of the cell wall in plant immunity

DEFF Research Database (Denmark)

Malinovsky, Frederikke Gro; Fangel, Jonatan Ulrik; Willats, William George Tycho

2014-01-01

The battle between plants and microbes is evolutionarily ancient, highly complex, and often co-dependent. A primary challenge for microbes is to breach the physical barrier of host cell walls whilst avoiding detection by the plant's immune receptors. While some receptors sense conserved microbial...... features, others monitor physical changes caused by an infection attempt. Detection of microbes leads to activation of appropriate defense responses that then challenge the attack. Plant cell walls are formidable and dynamic barriers. They are constructed primarily of complex carbohydrates joined...... by numerous distinct connection types, and are subject to extensive post-synthetic modification to suit prevailing local requirements. Multiple changes can be triggered in cell walls in response to microbial attack. Some of these are well described, but many remain obscure. The study of the myriad of subtle...

TH17 cells promote microbial killing and innate immune sensing of DNA via interleukin 26

KAUST Repository

Meller, Stephan

2015-07-13

Interleukin 17-producing helper T cells (TH 17 cells) have a major role in protection against infections and in mediating autoimmune diseases, yet the mechanisms involved are incompletely understood. We found that interleukin 26 (IL-26), a human TH17 cell-derived cytokine, is a cationic amphipathic protein that kills extracellular bacteria via membrane-pore formation. Furthermore, TH17 cell-derived IL-26 formed complexes with bacterial DNA and self-DNA released by dying bacteria and host cells. The resulting IL-26-DNA complexes triggered the production of type I interferon by plasmacytoid dendritic cells via activation of Toll-like receptor 9, but independently of the IL-26 receptor. These findings provide insights into the potent antimicrobial and proinflammatory function of TH17 cells by showing that IL-26 is a natural human antimicrobial that promotes immune sensing of bacterial and host cell death. © 2015 Nature America, Inc.

TH17 cells promote microbial killing and innate immune sensing of DNA via interleukin 26

KAUST Repository

Meller, Stephan; Di Domizio, Jeremy; Voo, Kui S; Friedrich, Heike C; Chamilos, Georgios; Ganguly, Dipyaman; Conrad, Curdin; Gregorio, Josh; Le Roy, Didier; Roger, Thierry; Ladbury, John E; Homey, Bernhard; Watowich, Stanley; Modlin, Robert L; Kontoyiannis, Dimitrios P; Liu, Yong-Jun; Arold, Stefan T.; Gilliet, Michel

2015-01-01

Interleukin 17-producing helper T cells (TH 17 cells) have a major role in protection against infections and in mediating autoimmune diseases, yet the mechanisms involved are incompletely understood. We found that interleukin 26 (IL-26), a human TH17 cell-derived cytokine, is a cationic amphipathic protein that kills extracellular bacteria via membrane-pore formation. Furthermore, TH17 cell-derived IL-26 formed complexes with bacterial DNA and self-DNA released by dying bacteria and host cells. The resulting IL-26-DNA complexes triggered the production of type I interferon by plasmacytoid dendritic cells via activation of Toll-like receptor 9, but independently of the IL-26 receptor. These findings provide insights into the potent antimicrobial and proinflammatory function of TH17 cells by showing that IL-26 is a natural human antimicrobial that promotes immune sensing of bacterial and host cell death. © 2015 Nature America, Inc.

A method for high purity intestinal epithelial cell culture from adult human and murine tissues for the investigation of innate immune function.

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Graves, Christina L; Harden, Scott W; LaPato, Melissa; Nelson, Michael; Amador, Byron; Sorenson, Heather; Frazier, Charles J; Wallet, Shannon M

2014-12-01

Intestinal epithelial cells (IECs) serve as an important physiologic barrier between environmental antigens and the host intestinal immune system. Thus, IECs serve as a first line of defense and may act as sentinel cells during inflammatory insults. Despite recent renewed interest in IEC contributions to host immune function, the study of primary IEC has been hindered by lack of a robust culture technique, particularly for small intestinal and adult tissues. Here, a novel adaptation for culture of primary IEC is described for human duodenal organ donor tissue as well as duodenum and colon of adult mice. These epithelial cell cultures display characteristic phenotypes and are of high purity. In addition, the innate immune function of human primary IEC, specifically with regard to Toll-like receptor (TLR) expression and microbial ligand responsiveness, is contrasted with a commonly used intestinal epithelial cell line (HT-29). Specifically, TLR expression at the mRNA level and production of cytokine (IFNγ and TNFα) in response to TLR agonist stimulation is assessed. Differential expression of TLRs as well as innate immune responses to ligand stimulation is observed in human-derived cultures compared to that of HT-29. Thus, use of this adapted method to culture primary epithelial cells from adult human donors and from adult mice will allow for more appropriate studies of IECs as innate immune effectors. Published by Elsevier B.V.

Induction of cell-mediated immunity against B16-BL6 melanoma in mice vaccinated with cells modified by hydrostatic pressure and chemical crosslinking.

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Eisenthal, A; Ramakrishna, V; Skornick, Y; Shinitzky, M

1993-05-01

In the preceding paper we have demonstrated an increase in presentation of both major histocompatibility complex antigens (MHC) and a tumor-associated antigen of the weakly immunogenic B16 melanoma by a straight-forward technique. The method consists in modulating the tumor cell membrane by hydrostatic pressure and simultaneous chemical crosslinking of the cell-surface proteins. In B16-BL6 melanoma, the induced antigenic modulation was found to persist for over 48 h, which permitted the evaluation of the ability of modified B16-BL6 cells to induce immunity against unmodified B16-BL6 cells. In the present study, we have shown that a significant systemic immunity was induced only in mice that were immunized with modified B16-BL6 melanoma cells, whereas immunization with unmodified B16-BL6 cells had only a marginal effect when compared to the results in control sham-immunized mice. The induced immunity was specific since a single immunization affected the growth of B16-BL6 tumors but had no effect on MCA 106, an antigenically unrelated tumor. The addition of interleukin-2 to the immunization regimen had no effect on the antitumor responses induced by the modified B16-BL6 cells. The cell-mediated immunity conferred by immunization with treated B16-BL6 cells was confirmed in experiments in vitro where splenocytes from immunized mice could be sensitized to proliferate by the presence of B16-BL6 cells. In addition, the altered antigenicity of these melanoma cells appeared to correlate with their increased susceptibility to specific effectors. Thus, 51Cr-labeled B16-BL6 target cells, modified by pressure and crosslinking, in comparison to control labeled target cells, were lysed in much greater numbers by effectors such as lymphokine-activated killer cells and allogeneic cytotoxic lymphocytes (anti-H-2b), while such cells remained resistant to lysis by natural killer cells. Our findings indicate that the physical and chemical modifications of the tumor cells that are

Alcohol, aging, and innate immunity.

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Boule, Lisbeth A; Kovacs, Elizabeth J

2017-07-01

The global population is aging: in 2010, 8% of the population was older than 65 y, and that is expected to double to 16% by 2050. With advanced age comes a heightened prevalence of chronic diseases. Moreover, elderly humans fair worse after acute diseases, namely infection, leading to higher rates of infection-mediated mortality. Advanced age alters many aspects of both the innate and adaptive immune systems, leading to impaired responses to primary infection and poor development of immunologic memory. An often overlooked, yet increasingly common, behavior in older individuals is alcohol consumption. In fact, it has been estimated that >40% of older adults consume alcohol, and evidence reveals that >10% of this group is drinking more than the recommended limit by the National Institute on Alcohol Abuse and Alcoholism. Alcohol consumption, at any level, alters host immune responses, including changes in the number, phenotype, and function of innate and adaptive immune cells. Thus, understanding the effect of alcohol ingestion on the immune system of older individuals, who are already less capable of combating infection, merits further study. However, there is currently almost nothing known about how drinking alters innate immunity in older subjects, despite innate immune cells being critical for host defense, resolution of inflammation, and maintenance of immune homeostasis. Here, we review the effects of aging and alcohol consumption on innate immune cells independently and highlight the few studies that have examined the effects of alcohol ingestion in aged individuals. © Society for Leukocyte Biology.

A novel mechanism of bacterial toxin transfer within host blood cell-derived microvesicles.

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Anne-lie Ståhl

2015-02-01

Full Text Available Shiga toxin (Stx is the main virulence factor of enterohemorrhagic Escherichia coli, which are non-invasive strains that can lead to hemolytic uremic syndrome (HUS, associated with renal failure and death. Although bacteremia does not occur, bacterial virulence factors gain access to the circulation and are thereafter presumed to cause target organ damage. Stx was previously shown to circulate bound to blood cells but the mechanism by which it would potentially transfer to target organ cells has not been elucidated. Here we show that blood cell-derived microvesicles, shed during HUS, contain Stx and are found within patient renal cortical cells. The finding was reproduced in mice infected with Stx-producing Escherichia coli exhibiting Stx-containing blood cell-derived microvesicles in the circulation that reached the kidney where they were transferred into glomerular and peritubular capillary endothelial cells and further through their basement membranes followed by podocytes and tubular epithelial cells, respectively. In vitro studies demonstrated that blood cell-derived microvesicles containing Stx undergo endocytosis in glomerular endothelial cells leading to cell death secondary to inhibited protein synthesis. This study demonstrates a novel virulence mechanism whereby bacterial toxin is transferred within host blood cell-derived microvesicles in which it may evade the host immune system.

Immune Responses Involved in Mycobacterium Tuberculosis Infection

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Roghayeh Teimourpour

2016-09-01

Full Text Available Background and Objectives: Mycobacterium tuberculosis is the causative agent of tuberculosis (TB. Approximately one-third of the world's population is infected with M. tuberculosis. Despite the availability of drug and vaccine, it remains one of the leading causes of death in humans especially in developing countries. Epidemiological studies have indicated that only 10-30% of people exposed to tubercle bacillus are infected with M. tuberculosis, and at least 90% of the infected people finally do not acquire TB. The studies have indicated that the host efficient immune system has essential roles in the control of TB infection such that the highest rate of mortality and morbidity is seen in immunocompromised patients such as people infected with HIV. M. tuberculosis is an obligatory intracellular bacterium. It enters the body mainly through the respiratory tract and alveolar macrophages combat this pathogen most commonly. In addition to alveolar macrophages, various T-cell subpopulations need to be activated to overcome this bacterium's resistance to the host defense systems. CD4+ T cells, through production of several cytokines such as IFN-γ and TNF-α, and CD8+ T cells, through cytotoxic activities and induction of apoptosis in infected cells, play critical roles in inducing appropriate immune responses against M. tuberculosis. Although cell-mediated immunity is the cornerstone of host responses against TB and the recent studies have provided evidence for the importance of humoral and innate immune system in the control of TB, a profound understanding of the immune responses would provide a basis for development of new generations of vaccines and drugs. The present study addresses immune responses involved in M. tuberculosis infection.

Genetics and Molecular Biology of Epstein-Barr Virus-Encoded BART MicroRNA: A Paradigm for Viral Modulation of Host Immune Response Genes and Genome Stability

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David H. Dreyfus

2017-01-01

Full Text Available Epstein-Barr virus, a ubiquitous human herpesvirus, is associated through epidemiologic evidence with common autoimmune syndromes and cancers. However, specific genetic mechanisms of pathogenesis have been difficult to identify. In this review, the author summarizes evidence that recently discovered noncoding RNAs termed microRNA encoded by Epstein-Barr virus BARF (BamHI A right frame termed BART (BamHI A right transcripts are modulators of human immune response genes and genome stability in infected and bystander cells. BART expression is apparently regulated by complex feedback loops with the host immune response regulatory NF-κB transcription factors. EBV-encoded BZLF-1 (ZEBRA protein could also regulate BART since ZEBRA contains a terminal region similar to ankyrin proteins such as IκBα that regulate host NF-κB. BALF-2 (BamHI A left frame transcript, a viral homologue of the immunoglobulin and T cell receptor gene recombinase RAG-1 (recombination-activating gene-1, may also be coregulated with BART since BALF-2 regulatory sequences are located near the BART locus. Viral-encoded microRNA and viral mRNA transferred to bystander cells through vesicles, defective viral particles, or other mechanisms suggest a new paradigm in which bystander or hit-and-run mechanisms enable the virus to transiently or chronically alter human immune response genes as well as the stability of the human genome.

The aryl hydrocarbon receptor is a modulator of anti-viral immunity

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Head, Jennifer L.; Lawrence, B. Paige

2009-01-01

Although immune modulation by AhR ligands has been studied for many years, the impact of AhR activation on host defenses against viral infection has not, until recently, garnered much attention. The development of novel reagents and model systems, new information regarding antiviral immunity, and a growing appreciation for the global health threat posed by viruses have invigorated interest in understanding how environmental signals affect susceptibility to and pathological consequences of viral infection. Using influenza A virus as a model of respiratory viral infection, recent studies show that AhR activation cues signaling events in both leukocytes and non-immune cells. Functional alterations include suppressed lymphocyte responses and increased inflammation in the infected lung. AhR-mediated events within and extrinsic to hematopoietic cells has been investigated using bone marrow chimeras, which show that AhR alters different elements of the immune response by affecting different tissue targets. In particular, suppressed CD8+ T cell responses are due to deregulated events within leukocytes themselves, whereas increased neutrophil recruitment to and IFN-γ levels in the lung result from AhR-regulated events extrinsic to bone marrow-derived cells. This latter discovery suggests that epithelial and endothelial cells are overlooked targets of AhR-mediated changes in immune function. Further support that AhR influences host cell responses to viral infection are provided by several studies demonstrating that AhR interacts directly with viral proteins and affects viral latency. While AhR clearly modulates host responses to viral infection, we still have much to understand about the complex interactions between immune cells, viruses, and the host environment. PMID:19027719

Glycosylation of Candida albicans cell wall proteins is critical for induction of innate immune responses and apoptosis of epithelial cells.

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Jeanette Wagener

Full Text Available C. albicans is one of the most common fungal pathogen of humans, causing local and superficial mucosal infections in immunocompromised individuals. Given that the key structure mediating host-C. albicans interactions is the fungal cell wall, we aimed to identify features of the cell wall inducing epithelial responses and be associated with fungal pathogenesis. We demonstrate here the importance of cell wall protein glycosylation in epithelial immune activation with a predominant role for the highly branched N-glycosylation residues. Moreover, these glycan moieties induce growth arrest and apoptosis of epithelial cells. Using an in vitro model of oral candidosis we demonstrate, that apoptosis induction by C. albicans wild-type occurs in early stage of infection and strongly depends on intact cell wall protein glycosylation. These novel findings demonstrate that glycosylation of the C. albicans cell wall proteins appears essential for modulation of epithelial immunity and apoptosis induction, both of which may promote fungal pathogenesis in vivo.

Cytomegalovirus immune evasion of myeloid lineage cells.

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Brinkmann, Melanie M; Dağ, Franziska; Hengel, Hartmut; Messerle, Martin; Kalinke, Ulrich; Čičin-Šain, Luka

2015-06-01

Cytomegalovirus (CMV) evades the immune system in many different ways, allowing the virus to grow and its progeny to spread in the face of an adverse environment. Mounting evidence about the antiviral role of myeloid immune cells has prompted the research of CMV immune evasion mechanisms targeting these cells. Several cells of the myeloid lineage, such as monocytes, dendritic cells and macrophages, play a role in viral control, but are also permissive for CMV and are naturally infected by it. Therefore, CMV evasion of myeloid cells involves mechanisms that qualitatively differ from the evasion of non-CMV-permissive immune cells of the lymphoid lineage. The evasion of myeloid cells includes effects in cis, where the virus modulates the immune signaling pathways within the infected myeloid cell, and those in trans, where the virus affects somatic cells targeted by cytokines released from myeloid cells. This review presents an overview of CMV strategies to modulate and evade the antiviral activity of myeloid cells in cis and in trans.

Interaction of pathogens with host cholesterol metabolism.

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Sviridov, Dmitri; Bukrinsky, Michael

2014-10-01

Pathogens of different taxa, from prions to protozoa, target cellular cholesterol metabolism to advance their own development and to impair host immune responses, but also causing metabolic complications, for example, atherosclerosis. This review describes recent findings of how pathogens do it. A common theme in interaction between pathogens and host cholesterol metabolism is pathogens targeting lipid rafts of the host plasma membrane. Many intracellular pathogens use rafts as an entry gate, taking advantage of the endocytic machinery and high abundance of outward-looking molecules that can be used as receptors. At the same time, disruption of the rafts' functional capacity, achieved by the pathogens through a number of various means, impairs the ability of the host to generate immune response, thus helping pathogen to thrive. Pathogens cannot synthesize cholesterol, and salvaging host cholesterol helps pathogens build advanced cholesterol-containing membranes and assembly platforms. Impact on cholesterol metabolism is not limited to the infected cells; proteins and microRNAs secreted by infected cells affect lipid metabolism systemically. Given an essential role that host cholesterol metabolism plays in pathogen development, targeting this interaction may be a viable strategy to fight infections, as well as metabolic complications of the infections.

Suppression of adaptive immunity to heterologous antigens during Plasmodium infection through hemozoin-induced failure of dendritic cell function

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Phillips R

2006-04-01

Full Text Available Abstract Background Dendritic cells (DCs are central to the initiation and regulation of the adaptive immune response during infection. Modulation of DC function may therefore allow evasion of the immune system by pathogens. Significant depression of the host's systemic immune response to both concurrent infections and heterologous vaccines has been observed during malaria infection, but the mechanisms underlying this immune hyporesponsiveness are controversial. Results Here, we demonstrate that the blood stages of malaria infection induce a failure of DC function in vitro and in vivo, causing suboptimal activation of T cells involved in heterologous immune responses. This effect on T-cell activation can be transferred to uninfected recipients by DCs isolated from infected mice. Significantly, T cells activated by these DCs subsequently lack effector function, as demonstrated by a failure to migrate to lymphoid-organ follicles, resulting in an absence of B-cell responses to heterologous antigens. Fractionation studies show that hemozoin, rather than infected erythrocyte (red blood cell membranes, reproduces the effect of intact infected red blood cells on DCs. Furthermore, hemozoin-containing DCs could be identified in T-cell areas of the spleen in vivo. Conclusion Plasmodium infection inhibits the induction of adaptive immunity to heterologous antigens by modulating DC function, providing a potential explanation for epidemiological studies linking endemic malaria with secondary infections and reduced vaccine efficacy.

Filarial parasites develop faster and reproduce earlier in response to host immune effectors that determine filarial life expectancy.

Science.gov (United States)

Babayan, Simon A; Read, Andrew F; Lawrence, Rachel A; Bain, Odile; Allen, Judith E

2010-10-19

Humans and other mammals mount vigorous immune assaults against helminth parasites, yet there are intriguing reports that the immune response can enhance rather than impair parasite development. It has been hypothesized that helminths, like many free-living organisms, should optimize their development and reproduction in response to cues predicting future life expectancy. However, immune-dependent development by helminth parasites has so far eluded such evolutionary explanation. By manipulating various arms of the immune response of experimental hosts, we show that filarial nematodes, the parasites responsible for debilitating diseases in humans like river blindness and elephantiasis, accelerate their development in response to the IL-5 driven eosinophilia they encounter when infecting a host. Consequently they produce microfilariae, their transmission stages, earlier and in greater numbers. Eosinophilia is a primary host determinant of filarial life expectancy, operating both at larval and at late adult stages in anatomically and temporally separate locations, and is implicated in vaccine-mediated protection. Filarial nematodes are therefore able to adjust their reproductive schedules in response to an environmental predictor of their probability of survival, as proposed by evolutionary theory, thereby mitigating the effects of the immune attack to which helminths are most susceptible. Enhancing protective immunity against filarial nematodes, for example through vaccination, may be less effective at reducing transmission than would be expected and may, at worst, lead to increased transmission and, hence, pathology.

Filarial parasites develop faster and reproduce earlier in response to host immune effectors that determine filarial life expectancy.

Directory of Open Access Journals (Sweden)

Simon A Babayan

Full Text Available Humans and other mammals mount vigorous immune assaults against helminth parasites, yet there are intriguing reports that the immune response can enhance rather than impair parasite development. It has been hypothesized that helminths, like many free-living organisms, should optimize their development and reproduction in response to cues predicting future life expectancy. However, immune-dependent development by helminth parasites has so far eluded such evolutionary explanation. By manipulating various arms of the immune response of experimental hosts, we show that filarial nematodes, the parasites responsible for debilitating diseases in humans like river blindness and elephantiasis, accelerate their development in response to the IL-5 driven eosinophilia they encounter when infecting a host. Consequently they produce microfilariae, their transmission stages, earlier and in greater numbers. Eosinophilia is a primary host determinant of filarial life expectancy, operating both at larval and at late adult stages in anatomically and temporally separate locations, and is implicated in vaccine-mediated protection. Filarial nematodes are therefore able to adjust their reproductive schedules in response to an environmental predictor of their probability of survival, as proposed by evolutionary theory, thereby mitigating the effects of the immune attack to which helminths are most susceptible. Enhancing protective immunity against filarial nematodes, for example through vaccination, may be less effective at reducing transmission than would be expected and may, at worst, lead to increased transmission and, hence, pathology.

Immune cells in term and preterm labor

Science.gov (United States)

Gomez-Lopez, Nardhy; StLouis, Derek; Lehr, Marcus A; Sanchez-Rodriguez, Elly N; Arenas-Hernandez, Marcia

2014-01-01

Labor resembles an inflammatory response that includes secretion of cytokines/chemokines by resident and infiltrating immune cells into reproductive tissues and the maternal/fetal interface. Untimely activation of these inflammatory pathways leads to preterm labor, which can result in preterm birth. Preterm birth is a major determinant of neonatal mortality and morbidity; therefore, the elucidation of the process of labor at a cellular and molecular level is essential for understanding the pathophysiology of preterm labor. Here, we summarize the role of innate and adaptive immune cells in the physiological or pathological activation of labor. We review published literature regarding the role of innate and adaptive immune cells in the cervix, myometrium, fetal membranes, decidua and the fetus in late pregnancy and labor at term and preterm. Accumulating evidence suggests that innate immune cells (neutrophils, macrophages and mast cells) mediate the process of labor by releasing pro-inflammatory factors such as cytokines, chemokines and matrix metalloproteinases. Adaptive immune cells (T-cell subsets and B cells) participate in the maintenance of fetomaternal tolerance during pregnancy, and an alteration in their function or abundance may lead to labor at term or preterm. Also, immune cells that bridge the innate and adaptive immune systems (natural killer T (NKT) cells and dendritic cells (DCs)) seem to participate in the pathophysiology of preterm labor. In conclusion, a balance between innate and adaptive immune cells is required in order to sustain pregnancy; an alteration of this balance will lead to labor at term or preterm. PMID:24954221

Immune responses to metastases

International Nuclear Information System (INIS)

Herberman, R.B.; Wiltrout, R.H.; Gorelik, E.

1987-01-01

The authors present the changes in the immune system in tumor-bearing hosts that may influence the development of progression of metastases. Included are mononuclear cell infiltration of metastases; alterations in natural resistance mediated by natural killer cells and macrophages; development of specific immunity mediated by T-lymphocytes or antibodies; modulation of tumor-associated antigen expression; and the down-regulation of the immune response to the tumor by several suppressor mechanisms; the augmentation of the immune response and its potential for therapeutic application; includes the prophylaxis of metastases formation by NK cells; the therapy of metastases by augmentation NK-, macrophage-, or T-lymphocyte-mediated responses by biological response modifiers; and the transfer of anticancer activity by cytoxic T-lymphocytes or immunoconjugates of monoclonal antibodies with specificity for tumors

Dual microRNA Screens Reveal That the Immune-Responsive miR-181 Promotes Henipavirus Entry and Cell-Cell Fusion.

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Chwan Hong Foo

2016-10-01

Full Text Available Hendra and Nipah viruses (family Paramyxoviridae, genus Henipavirus are bat-borne viruses that cause fatal disease in humans and a range of other mammalian species. Gaining a deeper understanding of host pathways exploited by henipaviruses for infection may identify targets for new anti-viral therapies. Here we have performed genome-wide high-throughput agonist and antagonist screens at biosafety level 4 to identify host-encoded microRNAs (miRNAs impacting henipavirus infection in human cells. Members of the miR-181 and miR-17~93 families strongly promoted Hendra virus infection. miR-181 also promoted Nipah virus infection, but did not affect infection by paramyxoviruses from other genera, indicating specificity in the virus-host interaction. Infection promotion was primarily mediated via the ability of miR-181 to significantly enhance henipavirus-induced membrane fusion. Cell signalling receptors of ephrins, namely EphA5 and EphA7, were identified as novel negative regulators of henipavirus fusion. The expression of these receptors, as well as EphB4, were suppressed by miR-181 overexpression, suggesting that simultaneous inhibition of several Ephs by the miRNA contributes to enhanced infection and fusion. Immune-responsive miR-181 levels was also up-regulated in the biofluids of ferrets and horses infected with Hendra virus, suggesting that the host innate immune response may promote henipavirus spread and exacerbate disease severity. This study is the first genome-wide screen of miRNAs influencing infection by a clinically significant mononegavirus and nominates select miRNAs as targets for future anti-viral therapy development.

The role of lipids in host microbe interactions.

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Lang, Roland; Mattner, Jochen

2017-06-01

Lipids are one of the major subcellular constituents and serve as signal molecules, energy sources, metabolic precursors and structural membrane components in various organisms. The function of lipids can be modified by multiple biochemical processes such as (de-)phosphorylation or (de-)glycosylation, and the organization of fatty acids into distinct cellular pools and subcellular compartments plays a pivotal role for the morphology and function of various cell populations. Thus, lipids regulate, for example, phagosome formation and maturation within host cells and thus, are critical for the elimination of microbial pathogens. Vice versa, microbial pathogens can manipulate the lipid composition of phagosomal membranes in host cells, and thus avoid their delivery to phagolysosomes. Lipids of microbial origin belong also to the strongest and most versatile inducers of mammalian immune responses upon engagement of distinct receptors on myeloid and lymphoid cells. Furthermore, microbial lipid toxins can induce membrane injuries and cell death. Thus, we will review here selected examples for mutual host-microbe interactions within the broad and divergent universe of lipids in microbial defense, tissue injury and immune evasion.

Role and contribution of pulmonary CD103+ dendritic cells in the adaptive immune response to Mycobacterium tuberculosis.

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Koh, Vanessa Hui Qi; Ng, See Liang; Ang, Michelle Lay Teng; Lin, Wenwei; Ruedl, Christiane; Alonso, Sylvie

2017-01-01

Despite international control programmes, the global burden of tuberculosis remains enormous. Efforts to discover novel drugs have largely focused on targeting the bacterium directly. Alternatively, manipulating the host immune response may represent a valuable approach to enhance immunological clearance of the bacilli, but necessitates a deeper understanding of the immune mechanisms associated with protection against Mycobacterium tuberculosis infection. Here, we examined the various dendritic cells (DC) subsets present in the lung and draining lymph nodes (LN) from mice intra-tracheally infected with M. tuberculosis. We showed that although limited in number, pulmonary CD103 + DCs appeared to be involved in the initial transport of mycobacteria to the draining mediastinal LN and subsequent activation of T cells. Using CLEC9A-DTR transgenic mice enabling the inducible depletion of CD103 + DCs, we established that this DC subset contributes to the control of mycobacterial burden and plays a role in the early activation of T cells, in particular CD8 + T cells. Our findings thus support a previously unidentified role for pulmonary CD103 + DCs in the rapid mobilization of mycobacteria from the lungs to the draining LN soon after exposure to M. tuberculosis, which is a critical step for the development of the host adaptive immune response. Copyright © 2016 Elsevier Ltd. All rights reserved.

Immune system and melanoma biology: a balance between immunosurveillance and immune escape.

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Passarelli, Anna; Mannavola, Francesco; Stucci, Luigia Stefania; Tucci, Marco; Silvestris, Francesco

2017-12-01

Melanoma is one of the most immunogenic tumors and its relationship with host immune system is currently under investigation. Many immunomodulatory mechanisms, favoring melanomagenesis and progression, have been described to interfere with the disablement of melanoma recognition and attack by immune cells resulting in immune resistance and immunosuppression. This knowledge produced therapeutic advantages, such as immunotherapy, aiming to overcome the immune evasion. Here, we review the current advances in cancer immunoediting and focus on melanoma immunology, which involves a dynamic interplay between melanoma and immune system, as well as on effects of "targeted therapies" on tumor microenvironment for combination strategies.

CMV immune evasion and manipulation of the immune system with aging.

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Jackson, Sarah E; Redeker, Anke; Arens, Ramon; van Baarle, Debbie; van den Berg, Sara P H; Benedict, Chris A; Čičin-Šain, Luka; Hill, Ann B; Wills, Mark R

2017-06-01

Human cytomegalovirus (HCMV) encodes numerous proteins and microRNAs that function to evade the immune response and allow the virus to replicate and disseminate in the face of a competent innate and acquired immune system. The establishment of a latent infection by CMV, which if completely quiescent at the level of viral gene expression would represent an ultimate in immune evasion strategies, is not sufficient for lifelong persistence and dissemination of the virus. CMV needs to reactivate and replicate in a lytic cycle of infection in order to disseminate further, which occurs in the face of a fully primed secondary immune response. Without reactivation, latency itself would be redundant for the virus. It is also becoming clear that latency is not a totally quiescent state, but is characterized by limited viral gene expression. Therefore, the virus also needs immune evasion strategies during latency. An effective immune response to CMV is required or viral replication will cause morbidity and ultimately mortality in the host. There is clearly a complex balance between virus immune evasion and host immune recognition over a lifetime. This poses the important question of whether long-term evasion or manipulation of the immune response driven by CMV is detrimental to health. In this meeting report, three groups used the murine model of CMV (MCMV) to examine if the contribution of the virus to immune senescence is set by the (i) initial viral inoculum, (ii) inflation of T cell responses, (iii) or the balance between functionally distinct effector CD4+ T cells. The work of other groups studying the CMV response in humans is discussed. Their work asks whether the ability to make immune responses to new antigens is compromised by (i) age and HCMV carriage, (ii) long-term exposure to HCMV giving rise to an overall immunosuppressive environment and increased levels of latent virus, or (iii) adapted virus mutants (used as potential vaccines) that have the capacity to

Immune Recognition of the Epidemic Cystic Fibrosis Pathogen Burkholderia dolosa.

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Roux, Damien; Weatherholt, Molly; Clark, Bradley; Gadjeva, Mihaela; Renaud, Diane; Scott, David; Skurnik, David; Priebe, Gregory P; Pier, Gerald; Gerard, Craig; Yoder-Himes, Deborah R

2017-06-01

Burkholderia dolosa caused an outbreak in the cystic fibrosis (CF) clinic at Boston Children's Hospital from 1998 to 2005 and led to the infection of over 40 patients, many of whom died due to complications from infection by this organism. To assess whether B. dolosa significantly contributes to disease or is recognized by the host immune response, mice were infected with a sequenced outbreak B. dolosa strain, AU0158, and responses were compared to those to the well-studied CF pathogen Pseudomonas aeruginosa In parallel, mice were also infected with a polar flagellin mutant of B. dolosa to examine the role of flagella in B. dolosa lung colonization. The results showed a higher persistence in the host by B. dolosa strains, and yet, neutrophil recruitment and cytokine production were lower than those with P. aeruginosa The ability of host immune cells to recognize B. dolosa was then assessed, B. dolosa induced a robust cytokine response in cultured cells, and this effect was dependent on the flagella only when bacteria were dead. Together, these results suggest that B. dolosa can be recognized by host cells in vitro but may avoid or suppress the host immune response in vivo through unknown mechanisms. B. dolosa was then compared to other Burkholderia species and found to induce similar levels of cytokine production despite being internalized by macrophages more than Burkholderia cenocepacia strains. These data suggest that B. dolosa AU0158 may act differently with host cells and is recognized differently by immune systems than are other Burkholderia strains or species. Copyright © 2017 American Society for Microbiology.

Cytokines in the host response to Candida vaginitis: Identifying a role for non-classical immune mediators, S100 alarmins

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Yano, Junko; Noverr, Mairi C.; Fidel, Paul L.

2011-01-01

Vulvovaginal candidiasis (VVC), caused by Candida albicans, affects a significant number of women during their reproductive years. More than two decades of research have been focused on the mechanisms associated with susceptibility or resistance to symptomatic infection. Adaptive immunity by Th1-type CD4+ T cells and downstream cytokine responses are considered the predominant host defense mechanisms against mucosal Candida infections. However, numerous clinical and animal studies have indicated no or limited protective role of cells and cytokines of the Th1 or Th2 lineage against vaginal infection. The role for Th17 is only now begun to be investigated in-depth for VVC with results already showing significant controversy. On the other hand, a clinical live-challenge study and an established animal model have shown that a symptomatic condition is intimately associated with the vaginal infiltration of polymorphonuclear leukocytes (PMNs) but with no effect on vaginal fungal burden. Subsequent studies identified S100A8 and S100A9 Alarmins as key chemotactic mediators of the acute PMN response. These chemotactic danger signals appear to be secreted by vaginal epithelial cells upon interaction and early adherence of Candida. Thus, instead of a putative immunodeficiency against Candida involving classical immune cells and cytokines of the adaptive response, the pathological inflammation in VVC is now considered a consequence of a non-productive innate response initiated by non-classical immune mediators. PMID:22182685

Theoretical analysis of the evolution of immune memory

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Magnus Carsten

2010-12-01

Full Text Available Abstract Background The ability of an immune system to remember pathogens improves the chance of the host to survive a second exposure to the same pathogen. This immunological memory has evolved in response to the pathogen environment of the hosts. In vertebrates, the memory of previous infection is physiologically accomplished by the development of memory T and B cells. Many questions concerning the generation and maintenance of immunological memory are still debated. Is there a limit to how many memory cells a host can generate and maintain? If there is a limit, how should new cells be incorporated into a filled memory compartment? And how many different pathogens should the immune system remember? Results In this study, we examine how memory traits evolve as a response to different pathogen environments using an individual-based model. We find that even without a cost related to the maintenance of a memory pool, the positive effect of bigger memory pool sizes saturates. The optimal diversity of a limited memory pool is determined by the probability of re-infection, rather than by the prevalence of a pathogen in the environment, or the frequency of exposure. Conclusions Relating immune memory traits to the pathogen environment of the hosts, our population biological framework sheds light on the evolutionary determinants of immune memory.

Effect of human papillomavirus infection on the immune system and its role in the course of cervical cancer.

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Song, Dan; Li, Hong; Li, Haibo; Dai, Jianrong

2015-08-01

Human papillomavirus (HPV) is widely known as a cause of cervical intraepithelial neoplasia (CIN) and cervical cancer. The mechanisms involved have been studied by numerous studies. The integration of the virus genome into the host cells results in the abnormal regulation of cell cycle control. HPV can also induce immune evasion of the infected cells, which enable the virus to be undetectable for long periods of time. The induction of immunotolerance of the host's immune system by the persistent infection of HPV is one of the most important mechanisms for cervical lesions. The present review elaborates on the roles of several types of immune cells, such as macrophages and natural killer cells, which are classified as innate immune cells, and dendritic cells (DCs), cluster of differentiation (CD)4 + /CD8 + T cells and regulatory T cells, which are classified as adaptive immune cells. HPV infection could effect the differentiation of these immune cells in a unique way, resulting in the host's immune tolerance to the infection. The immune system modifications induced by HPV infection include tumor-associated macrophage differentiation, a compromised cellular immune response, an abnormal imbalance between type 1 T-helper cells (Th1) and Th2 cells, regulatory T cell infiltration, and downregulated DC activation and maturation. To date, numerous types of preventative vaccines have been created to slow down carcinogenesis. Immune response activation-based therapeutic vaccine is becoming more and more attractive for the treatment of HPV-associated diseases.

Role of pathogen-derived cell wall carbohydrates and prostaglandin E2 in immune response and suppression of fish immunity by the oomycete Saprolegnia parasitica.

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Belmonte, Rodrigo; Wang, Tiehui; Duncan, Gary J; Skaar, Ida; Mélida, Hugo; Bulone, Vincent; van West, Pieter; Secombes, Christopher J

2014-11-01

Saprolegnia parasitica is a freshwater oomycete that is capable of infecting several species of fin fish. Saprolegniosis, the disease caused by this microbe, has a substantial impact on Atlantic salmon aquaculture. No sustainable treatment against saprolegniosis is available, and little is known regarding the host response. In this study, we examined the immune response of Atlantic salmon to S. parasitica infection and to its cell wall carbohydrates. Saprolegnia triggers a strong inflammatory response in its host (i.e., induction of interleukin-1β1 [IL-1β1], IL-6, and tumor necrosis factor alpha), while severely suppressing the expression of genes associated with adaptive immunity in fish, through downregulation of T-helper cell cytokines, antigen presentation machinery, and immunoglobulins. Oomycete cell wall carbohydrates were recognized by fish leukocytes, triggering upregulation of genes involved in the inflammatory response, similar to what is observed during infection. Our data suggest that S. parasitica is capable of producing prostaglandin [corrected] E2 (PGE2) in vitro, a metabolite not previously shown to be produced by oomycetes, and two proteins with homology to vertebrate enzymes known to play a role in prostaglandin biosynthesis have been identified in the oomycete genome. Exogenous PGE2 was shown to increase the inflammatory response in fish leukocytes incubated with cell wall carbohydrates while suppressing genes involved in cellular immunity (gamma interferon [IFN-γ] and the IFN-γ-inducible protein [γ-IP]). Inhibition of S. parasitica zoospore germination and mycelial growth by two cyclooxygenase inhibitors (aspirin and indomethacin) also suggests that prostaglandins may be involved in oomycete development. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

An update: Epstein-Barr virus and immune evasion via microRNA regulation.

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Zuo, Lielian; Yue, Wenxin; Du, Shujuan; Xin, Shuyu; Zhang, Jing; Liu, Lingzhi; Li, Guiyuan; Lu, Jianhong

2017-06-01

Epstein-Barr virus (EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategies to evade host immune responses. Emerging evidence has shown that microRNAs (miRNAs) are powerful regulators of the maintenance of cellular homeostasis. In this review, we summarize current progress on how EBV utilizes miRNAs for immune evasion. EBV encodes miRNAs targeting both viral and host genes involved in the immune response. The miRNAs are found in two gene clusters, and recent studies have demonstrated that lack of these clusters increases the CD4 + and CD8 + T cell response of infected cells. These reports strongly indicate that EBV miRNAs are critical for immune evasion. In addition, EBV is able to dysregulate the expression of a variety of host miRNAs, which influence multiple immune-related molecules and signaling pathways. The transport via exosomes of EBV-regulated miRNAs and viral proteins contributes to the construction and modification of the inflammatory tumor microenvironment. During EBV immune evasion, viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and pro-apoptosis molecules are involved. Our increasing knowledge of the role of miRNAs in immune evasion will improve the understanding of EBV persistence and help to develop new treatments for EBV-associated cancers and other diseases.

Nanomimics of host cell membranes block invasion and expose invasive malaria parasites.

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Najer, Adrian; Wu, Dalin; Bieri, Andrej; Brand, Françoise; Palivan, Cornelia G; Beck, Hans-Peter; Meier, Wolfgang

2014-12-23

The fight against most infectious diseases, including malaria, is often hampered by the emergence of drug resistance and lack or limited efficacies of vaccines. Therefore, new drugs, vaccines, or other strategies to control these diseases are needed. Here, we present an innovative nanotechnological strategy in which the nanostructure itself represents the active substance with no necessity to release compounds to attain therapeutic effect and which might act in a drug- and vaccine-like dual function. Invasion of Plasmodium falciparum parasites into red blood cells was selected as a biological model for the initial validation of this approach. Stable nanomimics-polymersomes presenting receptors required for parasite attachment to host cells-were designed to efficiently interrupt the life cycle of the parasite by inhibiting invasion. A simple way to build nanomimics without postformation modifications was established. First, a block copolymer of the receptor with a hydrophobic polymer was synthesized and then mixed with a polymersome-forming block copolymer. The resulting nanomimics bound parasite-derived ligands involved in the initial attachment to host cells and they efficiently blocked reinvasion of malaria parasites after their egress from host cells in vitro. They exhibited efficacies of more than 2 orders of magnitude higher than the soluble form of the receptor, which can be explained by multivalent interactions of several receptors on one nanomimic with multiple ligands on the infective parasite. In the future, our strategy might offer interesting treatment options for severe malaria or a way to modulate the immune response.

Viral (hepatitis C virus, hepatitis B virus, HIV) persistence and immune homeostasis

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Zhou, Yun; Zhang, Ying; Moorman, Jonathan P; Yao, Zhi Q; Jia, Zhan S

2014-01-01

Immune homeostasis is a host characteristic that maintains biological balance within a host. Humans have evolved many host defence mechanisms that ensure the survival of individuals upon encountering a pathogenic infection, with recovery or persistence from a viral infection being determined by both viral factors and host immunity. Chronic viral infections, such as hepatitis B virus, hepatitis C virus and HIV, often result in chronic fluctuating viraemia in the face of host cellular and humoral immune responses, which are dysregulated by multi-faceted mechanisms that are incompletely understood. This review attempts to illuminate the mechanisms involved in this process, focusing on immune homeostasis in the setting of persistent viral infection from the aspects of host defence mechanism, including interferon-stimulated genes, apolipoprotein B mRNA editing enzyme catalytic polypeptide 3 (APOBEC3), autophagy and interactions of various immune cells, cytokines and regulatory molecules. PMID:24965611

Proteomics and its applications to aquaculture in China: infection, immunity, and interaction of aquaculture hosts with pathogens.

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Peng, Xuan-Xian

2013-01-01

China is the largest fishery producer worldwide in term of its aquaculture output, and plays leading and decisive roles in international aquaculture development. To improve aquaculture output further and promote aquaculture business development, infectious diseases and immunity of fishes and other aquaculture species must be studied. In this regard, aquaculture proteomics has been widely carried out in China to get a better understanding of aquaculture host immunity and microbial pathogenesis as well as host-pathogen interactions, and to identify novel disease targets and vaccine candidates for therapeutic interventions. These proteomics studies include development of novel methods, assays, and advanced concepts in order to characterize proteomics mechanisms of host innate immune defense and microbial pathogenesis. This review article summarizes some recently published technical approaches and their applications to aquaculture proteomics with an emphasis on the responses of aquaculture animals to bacteria, viruses, and other aqua-environmental stresses, and development of broadly cross-protective vaccine candidates. The reviewed articles are those that have been published in international peer reviewed journals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Immunity to intestinal pathogens: lessons learned from Salmonella

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McSorley, Stephen J.

2014-01-01

Summary Salmonella are a common source of food or water-borne infection and cause a wide range of clinical disease in human and animal hosts. Salmonella are relatively easy to culture and manipulate in a laboratory setting, and the infection of laboratory animals induces robust innate and adaptive immune responses. Thus, immunologists have frequently turned to Salmonella infection models to expand understanding of immunity to intestinal pathogens. In this review, I summarize current knowledge of innate and adaptive immunity to Salmonella and highlight features of this response that have emerged from recent studies. These include the heterogeneity of the antigen-specific T-cell response to intestinal infection, the prominence of microbial mechanisms to impede T and B-cell responses, and the contribution of non-cognate pathways for elicitation of T-cell effector functions. Together, these different issues challenge an overly simplistic view of host-pathogen interaction during mucosal infection but also allow deeper insight into the real-world dynamic of protective immunity to intestinal pathogens. PMID:24942689

Immune Reconstitution Inflammatory Syndrome (IRIS): What pathologists should know.

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Nelson, Ann Marie; Manabe, Yukari C; Lucas, Sebastian B

2017-07-01

Antiretroviral therapy has significantly improved the quality and length of life for those patients able to access effective and sustained treatment. The resulting restoration of the immune response is associated with a change in the clinical presentation of opportunistic infections, and the histologic reaction to pathogens. A complex combination of alterations in host response across the stages of HIV infection has been documented over the past 3 decades. The defects are seen in both acute and chronic phases of inflammation and involve innate and adaptive immunity. In advanced stages of HIV infection, the marked disruption of lymphoid tissue and loss of follicular dendritic cells limits the host's ability to process antigen and mount specific responses to pathogens. There are qualitative and quantitative defects in CD4 T cells due to HIV infection. The resulting indirect effects include loss of cytokine production, dysregulation of B-cell function, loss of cellular mediated immunity and "holes" in the immunologic repertoire that may not be restored with the use of antiretroviral therapy. Immune reconstitution allows the host to respond to and control infection, but a significant number of patients will have atypical inflammatory syndromes during the recovery period. We briefly discuss the impact of HIV infection on the immune system and give an overview of the spectrum of conditions attributed to the Immune Reconstitution Inflammatory syndrome (IRIS). Copyright © 2017 Elsevier Inc. All rights reserved.

A Cross-Talk Between Microbiota-Derived Short-Chain Fatty Acids and the Host Mucosal Immune System Regulates Intestinal Homeostasis and Inflammatory Bowel Disease.

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Gonçalves, Pedro; Araújo, João Ricardo; Di Santo, James P

2018-02-15

Gut microbiota has a fundamental role in the energy homeostasis of the host and is essential for proper "education" of the immune system. Intestinal microbial communities are able to ferment dietary fiber releasing short-chain fatty acids (SCFAs). The SCFAs, particularly butyrate (BT), regulate innate and adaptive immune cell generation, trafficing, and function. For example, BT has an anti-inflammatory effect by inhibiting the recruitment and proinflammatory activity of neutrophils, macrophages, dendritic cells, and effector T cells and by increasing the number and activity of regulatory T cells. Gut microbial dysbiosis, ie, a microbial community imbalance, has been suggested to play a role in the development of inflammatory bowel disease (IBD). The relationship between dysbiosis and IBD has been difficult to prove, especially in humans, and is probably complex and dynamic, rather than one of a simple cause and effect relationship. However, IBD patients have dysbiosis with reduced numbers of SCFAs-producing bacteria and reduced BT concentration that is linked to a marked increase in the number of proinflammatory immune cells in the gut mucosa of these patients. Thus, microbial dysbiosis and reduced BT concentration may be a factor in the emergence and severity of IBD. Understanding the relationship between microbial dysbiosis and reduced BT concentration to IBD may lead to novel therapeutic interventions.

Immune Cells in Blood Recognize Tumors

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NCI scientists have developed a novel strategy for identifying immune cells circulating in the blood that recognize specific proteins on tumor cells, a finding they believe may have potential implications for immune-based therapies.

Relative Contribution of Th1 and Th17 Cells in Adaptive Immunity to Bordetella pertussis: Towards the Rational Design of an Improved Acellular Pertussis Vaccine

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Ross, Pádraig J.; Allen, Aideen C.; Walsh, Kevin; Misiak, Alicja; Lavelle, Ed C.; McLoughlin, Rachel M.; Mills, Kingston H. G.

2013-01-01

Whooping cough caused by Bordetella pertussis is a re-emerging infectious disease despite the introduction of safer acellular pertussis vaccines (Pa). One explanation for this is that Pa are less protective than the more reactogenic whole cell pertussis vaccines (Pw) that they replaced. Although Pa induce potent antibody responses, and protection has been found to be associated with high concentrations of circulating IgG against vaccine antigens, it has not been firmly established that host protection induced with this vaccine is mediated solely by humoral immunity. The aim of this study was to examine the relative contribution of Th1 and Th17 cells in host immunity to infection with B. pertussis and in immunity induced by immunization with Pw and Pa and to use this information to help rationally design a more effective Pa. Our findings demonstrate that Th1 and Th17 both function in protective immunity induced by infection with B. pertussis or immunization with Pw. In contrast, a current licensed Pa, administered with alum as the adjuvant, induced Th2 and Th17 cells, but weak Th1 responses. We found that IL-1 signalling played a central role in protective immunity induced with alum-adsorbed Pa and this was associated with the induction of Th17 cells. Pa generated strong antibody and Th2 responses, but was fully protective in IL-4-defective mice, suggesting that Th2 cells were dispensable. In contrast, Pa failed to confer protective immunity in IL-17A-defective mice. Bacterial clearance mediated by Pa-induced Th17 cells was associated with cell recruitment to the lungs after challenge. Finally, protective immunity induced by an experimental Pa could be enhanced by substituting alum with a TLR agonist that induces Th1 cells. Our findings demonstrate that alum promotes protective immunity through IL-1β-induced IL-17A production, but also reveal that optimum protection against B. pertussis requires induction of Th1, but not Th2 cells. PMID:23592988

A novel Meloidogyne graminicola effector, MgMO237, interacts with multiple host defence-related proteins to manipulate plant basal immunity and promote parasitism.

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Chen, Jiansong; Hu, Lili; Sun, Longhua; Lin, Borong; Huang, Kun; Zhuo, Kan; Liao, Jinling

2018-02-27

Plant-parasitic nematodes can secrete effector proteins into the host tissue to facilitate their parasitism. In this study, we report a novel effector protein, MgMO237, from Meloidogyne graminicola, which is exclusively expressed within the dorsal oesophageal gland cell and markedly up-regulated in parasitic third-/fourth-stage juveniles of M. graminicola. Transient expression of MgMO237 in protoplasts from rice roots showed that MgMO237 was localized in the cytoplasm and nucleus of the host cells. Rice plants overexpressing MgMO237 showed an increased susceptibility to M. graminicola. In contrast, rice plants expressing RNA interference vectors targeting MgMO237 showed an increased resistance to M. graminicola. In addition, yeast two-hybrid and co-immunoprecipitation assays showed that MgMO237 interacted specifically with three rice endogenous proteins, i.e. 1,3-β-glucan synthase component (OsGSC), cysteine-rich repeat secretory protein 55 (OsCRRSP55) and pathogenesis-related BetvI family protein (OsBetvI), which are all related to host defences. Moreover, MgMO237 can suppress host defence responses, including the expression of host defence-related genes, cell wall callose deposition and the burst of reactive oxygen species. These results demonstrate that the effector MgMO237 probably promotes the parasitism of M. graminicola by interacting with multiple host defence-related proteins and suppressing plant basal immunity in the later parasitic stages of nematodes. © 2018 BSPP AND JOHN WILEY & SONS LTD.

Ironing Out the Wrinkles in Host Defense: Interactions between Iron Homeostasis and Innate Immunity

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Wang, Lijian; Cherayil, Bobby J.

2009-01-01

Iron is an essential micronutrient for both microbial pathogens and their mammalian hosts. Changes in iron availability and distribution have significant effects on pathogen virulence and on the immune response to infection. Recent advances in our understanding of the molecular regulation of iron metabolism have shed new light on how alterations in iron homeostasis both contribute to and influence innate immunity. In this article, we review what is currently known about the role of iron in the response to infection. PMID:20375603

Differences in the effects of host suppression on the adoptive immunotherapy of subcutaneous and visceral tumors

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Chang, A.E.; Shu, S.Y.; Chou, T.; Lafreniere, R.; Rosenberg, S.A.

1986-01-01

A syngeneic transplantable sarcoma induced in C57BL/6 mice, MCA 105, was used in studies to examine host suppression on the adoptive immunotherapy of established intradermal and experimentally induced pulmonary and hepatic metastases. Fresh immune splenocytes were generated from mice immunized to the MCA 105 tumor by a mixture of viable tumor cells and Corynebacterium parvum. The adoptive immunotherapy of intradermal MCA 105 tumor with immune cells required prior immunosuppression of the recipient by sublethal irradiation with 500 R or T-cell depletion. The effect of whole-body sublethal irradiation appeared to eliminate a systemic host suppression mechanism, since partialbody irradiation involving the tumor-bearing area did not permit successful immunotherapy. Host irradiation was not required to achieve successful immunotherapy of experimentally induced pulmonary or hepatic metastases. In nonirradiated recipients bearing both intradermal and pulmonary tumors, host suppression did not affect the function of transferred immune cells to induce regression of pulmonary metastases. Thus, suppression of adoptive immunotherapy appears to be relevant to tumors confined to the skin and subcutaneous tissue but not to tumor in visceral sites, such as the lung and liver

Roles of IFN-γ and γδ T cells in protective immunity against blood-stage malaria

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Shin-Ichi eInoue

2013-08-01

Full Text Available Malaria is caused by infection with Plasmodium parasites. Various studies with knockout mice have indicated that IFN-γ plays essential roles in protective immunity against blood-stage Plasmodium infection. However, after Plasmodium infection, increased IFN-γ production by various types of cells is involved not only in protective immunity, but also in immunopathology. Recent reports have shown that IFN-γ acts as a pro-inflammatory cytokine to induce not only the activation of macrophages, but also the generation of uncommon myelolymphoid progenitor cells after Plasmodium infection. However, the effects of IFN-γ on hematopoietic stem cells and progenitor cells are unclear. Therefore, the regulation of hematopoiesis by IFN-γ during Plasmodium infection remains to be clarified. Although there are conflicting reports concerning the significance of γδ T cells in protective immunity against Plasmodium infection, γδ T cells may respond to infection and produce IFN-γ as innate immune cells in the early phase of blood-stage malaria. Our recent studies have shown that γδ T cells express CD40 ligand and produce IFN-γ after Plasmodium infection, resulting in the enhancement of dendritic cell activation as part of the immune response to eliminate Plasmodium parasites. These data suggest that the function of γδ T cells is similar to that of NK cells. Although several reports suggest that γδ T cells have the potential to act as memory cells for various infections, it remains to be determined whether memory γδ T cells are generated by Plasmodium infection and whether memory γδ T cells can contribute to the host defense against re-infection with Plasmodium. Here, we summarize and discuss the effects of IFN-γ and the various functions of γδ T cells in blood-stage Plasmodium infection.

Studies on cross-immunity among syngeneic tumors by immunization with gamma-irradiated tumor cells

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Ito, Izumi

1977-01-01

In order to clarify whether cross-immunity among 3-methyl-cholanthrene (MCA)-induced sarcomas in C3H/He mice can be established or not, transplantations of syngeneic tumors were carried out in mice immunized with gamma-irradiated (13,000 rad 60 Co) tumor cells and in those immunized with living tumor cells thereafter. The following results were obtained. By using immunizing procedure with only gamma-irradiated tumor cells, a pair of tumors originating from one and the same mouse showed cross-resistance to each other. However, no such evidence was seen among tumors originating from different mice. Cross-immunity among syngeneic tumors originating from different mice could be clearly observed, when immunizing procedure using living tumor cells was added after the treatment with gamma-irradiated tumor cells. It was considered that common antigenicity among MCA-induced sarcoma cells was decreased by gamma-irradiation and that individual differences of tumor antigenecity were shown distinctly under such conditions. (auth.)

Enhanced host immune recognition of E.coli causing mastitis in CD-14 transgenic mice.

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Escherchia coli causes mastitis, an economically significant disease in dairy animals. E. coli endotoxin (lipopolysaccharide, LPS) when bound by host membrane proteins such as CD-14, causes release of pro-inflammatory cytokines recruiting neutrophils as a early innate immune response. Excessive pr...

Association of the Host Immune Response with Protection Using a Live Attenuated African Swine Fever Virus Model.

Science.gov (United States)

Carlson, Jolene; O'Donnell, Vivian; Alfano, Marialexia; Velazquez Salinas, Lauro; Holinka, Lauren G; Krug, Peter W; Gladue, Douglas P; Higgs, Stephen; Borca, Manuel V

2016-10-22

African swine fever (ASF) is a lethal hemorrhagic disease of swine caused by a double-stranded DNA virus, ASF virus (ASFV). There is no vaccine to prevent the disease and current control measures are limited to culling and restricting animal movement. Swine infected with attenuated strains are protected against challenge with a homologous virulent virus, but there is limited knowledge of the host immune mechanisms generating that protection. Swine infected with Pretoriuskop/96/4 (Pret4) virus develop a fatal severe disease, while a derivative strain lacking virulence-associated gene 9GL (Pret4Δ9GL virus) is completely attenuated. Swine infected with Pret4Δ9GL virus and challenged with the virulent parental virus at 7, 10, 14, 21, and 28 days post infection (dpi) showed a progressive acquisition of protection (from 40% at 7 dpi to 80% at 21 and 28 dpi). This animal model was used to associate the presence of host immune response (ASFV-specific antibody and interferon (IFN)-γ responses, or specific cytokine profiles) and protection against challenge. With the exception of ASFV-specific antibodies in survivors challenged at 21 and 28 dpi, no association between the parameters assessed and protection could be established. These results, encompassing data from 65 immunized swine, underscore the complexity of the system under study, suggesting that protection relies on the concurrence of different host immune mechanisms.

Secretion of Rhoptry and Dense Granule Effector Proteins by Nonreplicating Toxoplasma gondii Uracil Auxotrophs Controls the Development of Antitumor Immunity.

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Barbara A Fox

2016-07-01

Full Text Available Nonreplicating type I uracil auxotrophic mutants of Toxoplasma gondii possess a potent ability to activate therapeutic immunity to established solid tumors by reversing immune suppression in the tumor microenvironment. Here we engineered targeted deletions of parasite secreted effector proteins using a genetically tractable Δku80 vaccine strain to show that the secretion of specific rhoptry (ROP and dense granule (GRA proteins by uracil auxotrophic mutants of T. gondii in conjunction with host cell invasion activates antitumor immunity through host responses involving CD8α+ dendritic cells, the IL-12/interferon-gamma (IFN-γ TH1 axis, as well as CD4+ and CD8+ T cells. Deletion of parasitophorous vacuole membrane (PVM associated proteins ROP5, ROP17, ROP18, ROP35 or ROP38, intravacuolar network associated dense granule proteins GRA2 or GRA12, and GRA24 which traffics past the PVM to the host cell nucleus severely abrogated the antitumor response. In contrast, deletion of other secreted effector molecules such as GRA15, GRA16, or ROP16 that manipulate host cell signaling and transcriptional pathways, or deletion of PVM associated ROP21 or GRA3 molecules did not affect the antitumor activity. Association of ROP18 with the PVM was found to be essential for the development of the antitumor responses. Surprisingly, the ROP18 kinase activity required for resistance to IFN-γ activated host innate immunity related GTPases and virulence was not essential for the antitumor response. These data show that PVM functions of parasite secreted effector molecules, including ROP18, manipulate host cell responses through ROP18 kinase virulence independent mechanisms to activate potent antitumor responses. Our results demonstrate that PVM associated rhoptry effector proteins secreted prior to host cell invasion and dense granule effector proteins localized to the intravacuolar network and host nucleus that are secreted after host cell invasion coordinately

Effects of juvenile host density and food availability on adult immune response, parasite resistance and virulence in a Daphnia-parasite system.

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Corine N Schoebel

Full Text Available Host density can increase infection rates and reduce host fitness as increasing population density enhances the risk of becoming infected either through increased encounter rate or because host condition may decline. Conceivably, potential hosts could take high host density as a cue to up-regulate their defence systems. However, as host density usually covaries with food availability, it is difficult to examine the importance of host density in isolation. Thus, we performed two full-factorial experiments that varied juvenile densities of Daphnia magna (a freshwater crustacean and food availability independently. We also included a simulated high-density treatment, where juvenile experimental animals were kept in filtered media that previously maintained Daphnia at high-density. Upon reaching adulthood, we exposed the Daphnia to their sterilizing bacterial parasite, Pasteuria ramosa, and examined how the juvenile treatments influenced the likelihood and severity of infection (Experiment I and host immune investment (Experiment II. Neither juvenile density nor food treatments affected the likelihood of infection; however, well-fed hosts that were well-fed as juveniles produced more offspring prior to sterilization than their less well-fed counterparts. By contrast, parasite growth was independent of host juvenile resources or host density. Parasite-exposed hosts had a greater number of circulating haemocytes than controls (i.e., there was a cellular immune response, but the magnitude of immune response was not mediated by food availability or host density. These results suggest that density dependent effects on disease arise primarily through correlated changes in food availability: low food could limit parasitism and potentially curtail epidemics by reducing both the host's and parasite's reproduction as both depend on the same food.

The Major Players in Adaptive Immunity-Cell-mediated Immunity

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 6. The Major Players in Adaptive Immunity - Cell-mediated Immunity. Asma Ahmed Banishree Saha Anand Patwardhan Shwetha Shivaprasad Dipankar Nandi. General Article Volume 14 Issue 6 June 2009 pp 610-621 ...

The fungal quorum-sensing molecule farnesol activates innate immune cells but suppresses cellular adaptive immunity.

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Leonhardt, Ines; Spielberg, Steffi; Weber, Michael; Albrecht-Eckardt, Daniela; Bläss, Markus; Claus, Ralf; Barz, Dagmar; Scherlach, Kirstin; Hertweck, Christian; Löffler, Jürgen; Hünniger, Kerstin; Kurzai, Oliver

2015-03-17

important for fungal clearance and protective immunity. We show that farnesol is able to enhance inflammation by inducing activation of neutrophils and monocytes. At the same time, farnesol impairs differentiation of monocytes into immature dendritic cells (iDC) by modulating surface phenotype, cytokine release and migrational behavior. Consequently, iDC generated in the presence of farnesol are unable to induce proper T cell responses and fail to secrete Th1 promoting interleukin 12 (IL-12). As farnesol induced down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, desensitization to GM-CSF could potentially explain transcriptional reprofiling of iDC effector molecules. Taken together, our data show that farnesol can also mediate Candida-host communication and is able to act as a virulence factor. Copyright © 2015 Leonhardt et al.

Transfer of immunity by transfer of bone marrow cells: T-cell dependency

International Nuclear Information System (INIS)

Marusic, M.

1978-01-01

Thymectomized, lethally irradiated mice reconstituted with normal bone marrow cells succumbed when challenged ip with rat Yoshida ascites sarcoma (YAS) cells 40 days after irradiation and reconstitution. In contrast, thymectomized irradiated mice reconstituted with bone marrow cells from YAS-immune donors rejected the subsequent tumor challenge. Pretreatment of the bone marrow cells from immune donors with anti-Thy 1.2 antiserum and complement completely abolished the transfer of anti-YAS resistance. Bone marrow cells from donors thymectomized 2 months before immunization enabled almost all recipients to reject YAS, but bone marrow cells from donors thymectomized 8 months before immunization protected only 50 percent of the recipients. Further analysis showed that mice thymectomized 8 months before immunization failed to generate anti-YAS antibody response, whereas the antibody response of mice thymectomized 2 months before immunization did not differ from that of non-thymectomized age-matched control mice. The data suggest that the immune reaction of mice against xenogeneic YAS requires long-lived T 2 lymphocytes

Autoimmunity in Arabidopsis acd11 Is Mediated by Epigenetic Regulation of an Immune Receptor

DEFF Research Database (Denmark)

Palma, K.; Thorgrimsen, S.; Malinovsky, F.G.

2010-01-01

Certain pathogens deliver effectors into plant cells to modify host protein targets and thereby suppress immunity. These target modifications can be detected by intracellular immune receptors, or Resistance (R) proteins, that trigger strong immune responses including localized host cell death....... The accelerated cell death 11 (acd11) "lesion mimic" mutant of Arabidopsis thaliana exhibits autoimmune phenotypes such as constitutive defense responses and cell death without pathogen perception. ACD11 encodes a putative sphingosine transfer protein, but its precise role during these processes is unknown......, and that cell death in other lesion mimic mutants may also be caused by inappropriate activation of R genes. Moreover, SDG8 is required for basal and R protein-mediated pathogen resistance in Arabidopsis, revealing the importance of chromatin remodeling as a key process in plant innate immunity....

Conserved host response to highly pathogenic avian influenza virus infection in human cell culture, mouse and macaque model systems

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McDermott Jason E

2011-11-01

Full Text Available Abstract Background Understanding host response to influenza virus infection will facilitate development of better diagnoses and therapeutic interventions. Several different experimental models have been used as a proxy for human infection, including cell cultures derived from human cells, mice, and non-human primates. Each of these systems has been studied extensively in isolation, but little effort has been directed toward systematically characterizing the conservation of host response on a global level beyond known immune signaling cascades. Results In the present study, we employed a multivariate modeling approach to characterize and compare the transcriptional regulatory networks between these three model systems after infection with a highly pathogenic avian influenza virus of the H5N1 subtype. Using this approach we identified functions and pathways that display similar behavior and/or regulation including the well-studied impact on the interferon response and the inflammasome. Our results also suggest a primary response role for airway epithelial cells in initiating hypercytokinemia, which is thought to contribute to the pathogenesis of H5N1 viruses. We further demonstrate that we can use a transcriptional regulatory model from the human cell culture data to make highly accurate predictions about the behavior of important components of the innate immune system in tissues from whole organisms. Conclusions This is the first demonstration of a global regulatory network modeling conserved host response between in vitro and in vivo models.

Small hypoxia-primed mesenchymal stem cells attenuate graft-versus-host disease

KAUST Repository

Kim, YongHwan

2018-05-22

Mesenchymal stem cells (MSCs) are of particular interest for the treatment of immune-related diseases due to their immunosuppressive capacity. Here, we show that Small MSCs primed with Hypoxia and Calcium ions (SHC-MSCs) exhibit enhanced stemness and immunomodulatory functions for treating allogeneic conflicts. Compared with naïve cultured human umbilical cord blood-derived MSCs, SHC-MSCs were resistant to passage-dependent senescence mediated via the monocyte chemoattractant protein-1 and p53/p21 cascade and secreted large amounts of pro-angiogenic and immunomodulatory factors, resulting in suppression of T-cell proliferation. SHC-MSCs showed DNA demethylation in pluripotency, germline, and imprinted genes similarly to very small embryonic-like stem cells, suggesting a potential mutual relationship. Genome-wide DNA methylome and transcriptome analyses indicated that genes related to immune modulation, cell adhesion, and the cell cycle were up-regulated in SHC-MSCs. Particularly, polo-like kinase-1 (PLK1), zinc-finger protein-143, dehydrogenase/reductase-3, and friend-of-GATA2 play a key role in the beneficial effects of SHC-MSCs. Administration of SHC-MSCs or PLK1-overexpressing MSCs significantly ameliorated symptoms of graft-versus-host disease (GVHD) in a humanized mouse model, resulting in significantly improved survival, less weight loss, and reduced histopathologic injuries in GVHD target organs compared with naïve MSC-infused mice. Collectively, our findings suggest that SHC-MSCs can improve the clinical treatment of allogeneic conflicts, including GVHD.

Intestinal stromal cells in mucosal immunity and homeostasis.

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Owens, B M J; Simmons, A

2013-03-01

A growing body of evidence suggests that non-hematopoietic stromal cells of the intestine have multiple roles in immune responses and inflammation at this mucosal site. Despite this, many still consider gut stromal cells as passive structural entities, with past research focused heavily on their roles in fibrosis, tumor progression, and wound healing, rather than their contributions to immune function. In this review, we discuss our current knowledge of stromal cells in intestinal immunity, highlighting the many immunological axes in which stromal cells have a functional role. We also consider emerging data that broaden the potential scope of their contribution to immunity in the gut and argue that these so-called "non-immune" cells are reclassified in light of their diverse contributions to intestinal innate immunity and the maintenance of mucosal homeostasis.

A morphological and immunophenotypic map of the immune response in Merkel cell carcinoma.

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Walsh, Noreen M; Fleming, Kirsten E; Hanly, John G; Dakin Hache, Kelly; Doucette, Steve; Ferrara, Gerardo; Cerroni, Lorenzo

2016-06-01

The susceptibility of Merkel cell carcinoma to the host immune response has prompted a search for effective immunotherapy. CD8-positive T lymphocytes are considered key effectors of this response, but the cellular infiltrates also harbor tumor-protective agents. By developing a comprehensive morphological and immunophenotypic map of tumor-infiltrating lymphocytes (TILS) in Merkel cell carcinoma, we aimed to establish a useful template for future studies. Twenty-two cases (mean age, 79years [range, 52-95]; male-female ratio, 10:12) were studied. TILS were categorized as brisk (7), nonbrisk (9), and absent(6). Merkel cell polyomavirus (MCPyV)-positive (16) and -negative (6) cases were included, as were those with pure (18) and combined (4) morphologies. One MCPyV+ case had undergone spontaneous regression. Immunohistochemical markers included CD3, CD4, CD8, CD20, CD68, FoxP3, PD-1, and CD123. Statistical analysis used Fisher exact tests and Spearman correlations. There was a significant correlation between brisk TILs and MCPyV+ status (P=.025). CD8+ T lymphocytes predominated, were present in significantly higher proportions in brisk infiltrates (P=.003), and showed a significant predilection for the intratumoral environment (P=.003). Immune inhibitors including T regulatory cells (FOXP3+) and PD-1+ "exhausted" immunocytes were present in lower proportions. Our findings support (1) the link between a brisk immune response and MCPyV positivity, (2) the supremacy of CD8+ cells in effecting immunity, and (3) the incorporation of immune inhibitors within the global infiltrate. Efforts to therapeutically arm the "effectors" and disarm the "detractors" are well focused. These will likely have the greatest impact on MCPyV-positive cases. Copyright © 2016 Elsevier Inc. All rights reserved.

Protein-linked glycans in periodontal bacteria: prevalence and role at the immune interface.

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Settem, Rajendra P; Honma, Kiyonobu; Stafford, Graham P; Sharma, Ashu

2013-10-17

Protein modification with complex glycans is increasingly being recognized in many pathogenic and non-pathogenic bacteria, and is now thought to be central to the successful life-style of those species in their respective hosts. This review aims to convey current knowledge on the extent of protein glycosylation in periodontal pathogenic bacteria and its role in the modulation of the host immune responses. The available data show that surface glycans of periodontal bacteria orchestrate dendritic cell cytokine responses to drive T cell immunity in ways that facilitate bacterial persistence in the host and induce periodontal inflammation. In addition, surface glycans may help certain periodontal bacteria protect against serum complement attack or help them escape immune detection through glycomimicry. In this review we will focus mainly on the generalized surface-layer protein glycosylation system of the periodontal pathogen Tannerella forsythia in shaping innate and adaptive host immunity in the context of periodontal disease. In addition, we will also review the current state of knowledge of surface protein glycosylation and its potential for immune modulation in other periodontal pathogens.

Graft-versus-host reaction and immune function. III. Functional pre-T cells in the bone marrow of graft-versus-host-reactive mice displaying T cell immunodeficiency

International Nuclear Information System (INIS)

Seddik, M.; Seemayer, T.A.; Lapp, W.S.

1986-01-01

Studies were performed to determine whether pre-T cells develop normally in the bone marrow of mice displaying thymic dysplasia and T cell immunodeficiency as a consequence of a graft-versus-host (GVH) reaction. GVH reactions were induced in CBAxAF1 mice by the injection of A strain lymphoid cells. To test for the presence of pre-T cells in GVH-reactive mice, bone marrow from GVH-reactive mice (GVHBM) was injected into irradiated syngeneic F1 mice and 30-40 days later thymic morphology and function were studied. Morphology studies showed nearly normal thymic architectural restoration; moreover, such glands contained normal numbers of Thy-1-positive cells. Functional pre-T cells were evaluated by transferring thymocytes from the irradiated GVHBM-reconstituted mice into T-cell-deprived mice. These thymocytes reconstituted allograft reactivity, T helper cell function and Con A and PHA mitogen responses of T-cell-deprived mice. These results suggest that the pre-T cell population in the bone marrow is not affected by the GVH reaction. Therefore, the T cell immunodeficiency associated with the GVH reaction is not due to a deficiency of pre-T cells in the bone marrow but is more likely associated with GVH-induced thymic dysplasia

Foxp3(+) T cells regulate immunoglobulin a selection and facilitate diversification of bacterial species responsible for immune homeostasis.

Science.gov (United States)

Kawamoto, Shimpei; Maruya, Mikako; Kato, Lucia M; Suda, Wataru; Atarashi, Koji; Doi, Yasuko; Tsutsui, Yumi; Qin, Hongyan; Honda, Kenya; Okada, Takaharu; Hattori, Masahira; Fagarasan, Sidonia

2014-07-17

Foxp3(+) T cells play a critical role for the maintenance of immune tolerance. Here we show that in mice, Foxp3(+) T cells contributed to diversification of gut microbiota, particularly of species belonging to Firmicutes. The control of indigenous bacteria by Foxp3(+) T cells involved regulatory functions both outside and inside germinal centers (GCs), consisting of suppression of inflammation and regulation of immunoglobulin A (IgA) selection in Peyer's patches, respectively. Diversified and selected IgAs contributed to maintenance of diversified and balanced microbiota, which in turn facilitated the expansion of Foxp3(+) T cells, induction of GCs, and IgA responses in the gut through a symbiotic regulatory loop. Thus, the adaptive immune system, through cellular and molecular components that are required for immune tolerance and through the diversification as well as selection of antibody repertoire, mediates host-microbial symbiosis by controlling the richness and balance of bacterial communities required for homeostasis. Copyright © 2014 Elsevier Inc. All rights reserved.

The Tim-3-galectin-9 Secretory Pathway is Involved in the Immune Escape of Human Acute Myeloid Leukemia Cells

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Isabel Gonçalves Silva

2017-08-01

Full Text Available Acute myeloid leukemia (AML is a severe and often fatal systemic malignancy. Malignant cells are capable of escaping host immune surveillance by inactivating cytotoxic lymphoid cells. In this work we discovered a fundamental molecular pathway, which includes ligand-dependent activation of ectopically expressed latrophilin 1 and possibly other G-protein coupled receptors leading to increased translation and exocytosis of the immune receptor Tim-3 and its ligand galectin-9. This occurs in a protein kinase C and mTOR (mammalian target of rapamycin-dependent manner. Tim-3 participates in galectin-9 secretion and is also released in a free soluble form. Galectin-9 impairs the anti-cancer activity of cytotoxic lymphoid cells including natural killer (NK cells. Soluble Tim-3 prevents secretion of interleukin-2 (IL-2 required for the activation of cytotoxic lymphoid cells. These results were validated in ex vivo experiments using primary samples from AML patients. This pathway provides reliable targets for both highly specific diagnosis and immune therapy of AML.

Effects of ionizing radiation on the immune system

International Nuclear Information System (INIS)

Dubois, J.B.

1986-01-01

After reviewing the different lymphoid organs and the essential phases of the immune response, we studied the morphological and functional effects of ionizing radiation on the immunological system. Histologic changes in the lymph nodes, spleen, thymus, and different lymphocyte subpopulations were studied in relation with the radiation dose and irradiated volume (whole body irradiation, localized irradiation). Functional changes in the immune system induced by ionizing radiation were also investigated by a study of humoral-mediated immunity (antibody formation) and cell-mediated immunity (behavior of macrophages, B-cells, T suppressor cells, T helper cells, T effector cells, and natural killer cells). A study into the mechanisms of action of ionizing radiation and the immune processes it interferes with suggests several likely hypotheses (direct action on the immune cells, on their precursors, on seric mediators or on cell mediators). The effects on cancer patients' immune reactions of low radiation doses delivered to the various lymphoid organs are discussed, as well as the relationships between the host and the evolution of the tumor [fr

Defective pulmonary innate immune responses post-stem cell transplantation; review and results from one model system

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Racquel eDomingo-Gonzalez

2013-05-01

Full Text Available Infectious pulmonary complications limit the success of hematopoietic stem cell transplantation (HSCT as a therapy for malignant and nonmalignant disorders. Susceptibility to pathogens in both autologous and allogeneic HSCT recipients persists despite successful immune reconstitution. As studying the causal effects of these immune defects in the human population can be limiting, a bone marrow transplant (BMT mouse model can be used to understand the defect in mounting a productive innate immune response post-transplantation. When syngeneic BMT is performed, this system allows the study of BMT-induced alterations in innate immune cell function that are independent of the confounding effects of immunosuppressive therapy and graft-versus-host disease. Studies from several laboratories, including our own show that pulmonary susceptibility to bacterial infections post-BMT are largely due to alterations in the lung alveolar macrophages. Changes in these cells post-BMT include cytokine and eicosanoid dysregulations, scavenger receptor alterations, changes in micro RNA profiles, and alterations in intracellular signaling molecules that limit bacterial phagocytosis and killing. The changes that occur highlight mechanisms that promote susceptibility to infections commonly afflicting HSCT recipients and provide insight into therapeutic targets that may improve patient outcomes post-HSCT.

Viral degradasome hijacks mitochondria to suppress innate immunity

Science.gov (United States)

Goswami, Ramansu; Majumdar, Tanmay; Dhar, Jayeeta; Chattopadhyay, Saurabh; Bandyopadhyay, Sudip K; Verbovetskaya, Valentina; Sen, Ganes C; Barik, Sailen

2013-01-01

The balance between the innate immunity of the host and the ability of a pathogen to evade it strongly influences pathogenesis and virulence. The two nonstructural (NS) proteins, NS1 and NS2, of respiratory syncytial virus (RSV) are critically required for RSV virulence. Together, they strongly suppress the type I interferon (IFN)-mediated innate immunity of the host cells by degrading or inhibiting multiple cellular factors required for either IFN induction or response pathways, including RIG-I, IRF3, IRF7, TBK1 and STAT2. Here, we provide evidence for the existence of a large and heterogeneous degradative complex assembled by the NS proteins, which we named “NS-degradasome” (NSD). The NSD is roughly ∼300-750 kD in size, and its degradative activity was enhanced by the addition of purified mitochondria in vitro. Inside the cell, the majority of the NS proteins and the substrates of the NSD translocated to the mitochondria upon RSV infection. Genetic and pharmacological evidence shows that optimal suppression of innate immunity requires mitochondrial MAVS and mitochondrial motility. Together, we propose a novel paradigm in which the mitochondria, known to be important for the innate immune activation of the host, are also important for viral suppression of the innate immunity. PMID:23877405

Human immune cell targeting of protein nanoparticles - caveospheres

Science.gov (United States)

Glass, Joshua J.; Yuen, Daniel; Rae, James; Johnston, Angus P. R.; Parton, Robert G.; Kent, Stephen J.; de Rose, Robert

2016-04-01

Nanotechnology has the power to transform vaccine and drug delivery through protection of payloads from both metabolism and off-target effects, while facilitating specific delivery of cargo to immune cells. However, evaluation of immune cell nanoparticle targeting is conventionally restricted to monocultured cell line models. We generated human caveolin-1 nanoparticles, termed caveospheres, which were efficiently functionalized with monoclonal antibodies. Using this platform, we investigated CD4+ T cell and CD20+ B cell targeting within physiological mixtures of primary human blood immune cells using flow cytometry, imaging flow cytometry and confocal microscopy. Antibody-functionalization enhanced caveosphere binding to targeted immune cells (6.6 to 43.9-fold) within mixed populations and in the presence of protein-containing fluids. Moreover, targeting caveospheres to CCR5 enabled caveosphere internalization by non-phagocytic CD4+ T cells--an important therapeutic target for HIV treatment. This efficient and flexible system of immune cell-targeted caveosphere nanoparticles holds promise for the development of advanced immunotherapeutics and vaccines.

The cell-mediated immunity of Drosophila melanogaster: hemocyte lineages, immune compartments, microanatomy and regulation.

Science.gov (United States)

Honti, Viktor; Csordás, Gábor; Kurucz, Éva; Márkus, Róbert; Andó, István

2014-01-01

In the animal kingdom, innate immunity is the first line of defense against invading pathogens. The dangers of microbial and parasitic attacks are countered by similar mechanisms, involving the prototypes of the cell-mediated immune responses, the phagocytosis and encapsulation. Work on Drosophila has played an important role in promoting an understanding of the basic mechanisms of phylogenetically conserved modules of innate immunity. The aim of this review is to survey the developments in the identification and functional definition of immune cell types and the immunological compartments of Drosophila melanogaster. We focus on the molecular and developmental aspects of the blood cell types and compartments, as well as the dynamics of blood cell development and the immune response. Further advances in the characterization of the innate immune mechanisms in Drosophila will provide basic clues to the understanding of the importance of the evolutionary conserved mechanisms of innate immune defenses in the animal kingdom. Copyright © 2013 Elsevier Ltd. All rights reserved.

The immune response to sand fly salivary proteins and its influence on Leishmania immunity

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Regis eGomes

2012-05-01

Full Text Available Leishmaniasis is a vector-borne disease transmitted by bites of phlebotomine sand flies. During Leishmania transmission, sand fly saliva is co-inoculated with parasites into the skin of the mammalian host. Sand fly saliva consists of roughly thirty different salivary proteins, many with known roles linked to blood feeding facilitation. Apart from the anti-hemostatic capacity of saliva, several sand fly salivary proteins have been shown to be immunogenic upon multiple contacts with a mammalian host. Immunization with single immunogenic salivary proteins or exposure to uninfected bites can produce protective immune responses against leishmaniasis. These sand fly salivary proteins induce cellular immune responses and/or antibodies. Antibodies to saliva are not required for protection in a mouse model against leishmaniasis. A strong body of evidence points to the role for saliva-specific T cells producing IFN-γ in the form of a delayed-type hypersensitivity reaction at the bite site as the main protective response. Herein, we review immunity to sand fly salivary proteins in the context of its vector-parasite-host combinations and vaccine potential, as well as some recent advances to shed light on the mechanism of how an immune response to sand fly saliva protects against leishmaniasis.

[The role of gut microbiota in the regulation of the immune response].