scholarly journals New Insights on the Early Interaction Between Typhoid and Non-typhoid Salmonella Serovars and the Host Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Bárbara M. Schultz ◽  
Felipe Melo-Gonzalez ◽  
Geraldyne A. Salazar ◽  
Bárbara N. Porto ◽  
Claudia A. Riedel ◽  
...  
Keyword(s):  
Immune Responses ◽  
Mouse Models ◽  
Host Cells ◽  
Common Source ◽  
Bacterial Burden ◽  
Host Immune Responses ◽  
Wide Range ◽  
Animal Hosts ◽  
Early Interaction ◽  
Water Borne

Salmonella enterica is a common source of food and water-borne infections, causing a wide range of clinical ailments in both human and animal hosts. Immunity to Salmonella involves an interplay between different immune responses, which are rapidly initiated to control bacterial burden. However, Salmonella has developed several strategies to evade and modulate the host immune responses. In this sense, the main knowledge about the pathogenicity of this bacterium has been obtained by the study of mouse models with non-typhoidal serovars. However, this knowledge is not representative of all the pathologies caused by non-typhoidal serovars in the human. Here we review the most important features of typhoidal and non-typhoidal serovars and the diseases they cause in the human host, describing the virulence mechanisms used by these pathogens that have been identified in different models of infection.

scholarly journals Transcriptome Analysis of Mouse Brain Infected with Toxoplasma gondii

2013 ◽  
Vol 81 (10) ◽  
pp. 3609-3619 ◽  
Author(s):  
Sachi Tanaka ◽  
Maki Nishimura ◽  
Fumiaki Ihara ◽  
Junya Yamagishi ◽  
Yutaka Suzuki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Toxoplasma Gondii ◽  
Immune Responses ◽  
Mouse Brain ◽  
Transcriptome Analysis ◽  
Host Cells ◽  
Content Type ◽  
Host Immune Responses ◽  
Wide Range ◽  
The Brain

ABSTRACTToxoplasma gondiiis an obligate intracellular parasite that invades a wide range of vertebrate host cells. Chronic infections withT. gondiibecome established in the tissues of the central nervous system, where the parasites may directly or indirectly modulate neuronal function. However, the mechanisms underlying parasite-induced neuronal disorder in the brain remain unclear. This study evaluated host gene expression in mouse brain following infection withT. gondii. BALB/c mice were infected with the PLK strain, and after 32 days of infection, histopathological lesions in the frontal lobe were found to be more severe than in other areas of the brain. Total RNA extracted from infected and uninfected mouse brain samples was subjected to transcriptome analysis using RNA sequencing (RNA-seq). In theT. gondii-infected mice, 935 mouse brain genes were upregulated, whereas 12 genes were downregulated. GOstat analysis predicted that the upregulated genes were primarily involved in host immune responses and cell activation. Positive correlations were found between the numbers of parasites in the infected mouse brains and the expression levels of genes involved in host immune responses. In contrast, genes that had a negative correlation with parasite numbers were predicted to be involved in neurological functions, such as small-GTPase-mediated signal transduction and vesicle-mediated transport. Furthermore, differential gene expression was observed between mice exhibiting the clinical signs of toxoplasmosis and those that did not. Our findings may provide insights into the mechanisms underlying neurological changes duringT. gondiiinfection.

scholarly journals Extracellular Vesicles from Different Pneumococcal Serotypes Are Internalized by Macrophages and Induce Host Immune Responses

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1530
Author(s):  
Alfonso Olaya-Abril ◽  
Rafael Prados-Rosales ◽  
José A. González-Reyes ◽  
Arturo Casadevall ◽  
Liise-anne Pirofski ◽  
...  
Keyword(s):  
Immune Response ◽  
Biological Activity ◽  
Immune Responses ◽  
Extracellular Vesicles ◽  
Host Cells ◽  
Pneumococcal Serotypes ◽  
Human Pathogen ◽  
Host Immune Responses ◽  
Serotype 1 ◽  
Transient Loss

Bacterial extracellular vesicles are membranous ultrastructures released from the cell surface. They play important roles in the interaction between the host and the bacteria. In this work, we show how extracellular vesicles produced by four different serotypes of the important human pathogen, Streptococcus pneumoniae, are internalized by murine J774A.1 macrophages via fusion with the membrane of the host cells. We also evaluated the capacity of pneumococcal extracellular vesicles to elicit an immune response by macrophages. Macrophages treated with the vesicles underwent a serotype-dependent transient loss of viability, which was further reverted. The vesicles induced the production of proinflammatory cytokines, which was higher for serotype 1 and serotype 8-derived vesicles. These results demonstrate the biological activity of extracellular vesicles of clinically important pneumococcal serotypes.

scholarly journals The DBL-1/TGF-β signaling pathway regulates pathogen-specific innate immune responses in C. elegans

2021 ◽  
Author(s):  
Bhoomi Madhu ◽  
Tina L. Gumienny
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Defense Responses ◽  
C Elegans ◽  
Host Immune Responses ◽  
Wide Range ◽  
Independent Functions ◽  
Multiple Cell

Innate immunity in animals is orchestrated by multiple cell signaling pathways, including the TGF-β; superfamily pathway. While the role of TGF-β signaling in innate immunity has been clearly identified, the requirement for this pathway in generating specific, robust responses to different bacterial challenges has not been characterized. Here, we address the role of DBL-1/TGF-β in regulating signature host defense responses to a wide range of bacteria in C. elegans. This work reveals a role of DBL-1/TGF-β in animal survival, organismal behaviors, and molecular responses in different environments. Additionally, we identify a novel role for SMA-4/Smad that suggests both DBL-1/TGF-β-dependent and -independent functions in host avoidance responses. RNA-seq analyses and immunity reporter studies indicate DBL-1/TGF-β differentially regulates target gene expression upon exposure to different bacteria. Furthermore, the DBL-1/TGF-β pathway is itself differentially affected by the bacteria exposure. Collectively, these findings demonstrate bacteria-specific host immune responses regulated by the DBL-1/TGF-β signaling pathway.

scholarly journals Glycopeptides and -Mimetics to Detect, Monitor and Inhibit Bacterial and Viral Infections: Recent Advances and Perspectives

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1004 ◽  
Author(s):  
Sandra Behren ◽  
Ulrika Westerlind
Keyword(s):  
Cell Surface ◽  
Immune Responses ◽  
Viral Infections ◽  
Host Cells ◽  
Initial Contact ◽  
Host Immune Responses ◽  
Recent Advances ◽  
Multivalent Display ◽  
Important Objective ◽  
Pathogenic Infection

The initial contact of pathogens with host cells is usually mediated by their adhesion to glycan structures present on the cell surface in order to enable infection. Furthermore, glycans play important roles in the modulation of the host immune responses to infection. Understanding the carbohydrate-pathogen interactions are of importance for the development of novel and efficient strategies to either prevent, or interfere with pathogenic infection. Synthetic glycopeptides and mimetics thereof are capable of imitating the multivalent display of carbohydrates at the cell surface, which have become an important objective of research over the last decade. Glycopeptide based constructs may function as vaccines or anti-adhesive agents that interfere with the ability of pathogens to adhere to the host cell glycans and thus possess the potential to improve or replace treatments that suffer from resistance. Additionally, synthetic glycopeptides are used as tools for epitope mapping of antibodies directed against structures present on various pathogens and have become important to improve serodiagnostic methods and to develop novel epitope-based vaccines. This review will provide an overview of the most recent advances in the synthesis and application of glycopeptides and glycopeptide mimetics exhibiting a peptide-like backbone in glycobiology.

scholarly journals The effects of host heterogeneity on pathogen population structure

1999 ◽  
Vol 354 (1384) ◽  
pp. 711-719 ◽  
Author(s):  
Sunetra Gupta ◽  
Alison Galvani
Keyword(s):  
Immune Responses ◽  
High Frequency ◽  
Host Population ◽  
Immune Selection ◽  
Pathogen Population ◽  
Host Immune Responses ◽  
Wide Range ◽  
Specific Manner ◽  
Variable Antigen ◽  
The Individual

We have shown that among pathogens, populations may self–organize into strains with non–overlapping repertoires of antigenic variants as a consequence of strong immune selection operating on polymorphic antigens. Recently, we have also demonstrated that over a wide range of intermediate levels of immune selection, pathogens may still be structured into discrete strains, but different sets of non–overlapping pathogen types will replace each other in a cyclical or chaotic manner. These models assume that the ranking of antigens in terms of the strength of the induced immune response is the same for every host. However, host immune responses may be restricted by the genotype of the individual. To explore this issue, a mathematical model was constructed under the assumption that a proportion of the host population responds principally to a variable antigen while the remainder of the population responds principally to a conserved antigen. The results of this analysis indicate that discrete strain structure (DSS) will be maintained even with a high frequency of hosts that do not respond in a variant–specific manner. Furthermore, the range of the immune selection pressure over which DSS prevails is increased (and the region of cyclical or chaotic behaviour reduced) by the inclusion of hosts that respond in a cross–reactive rather than a variant–specific manner.

Drivers of persistent infection: pathogen-induced extracellular vesicles

2018 ◽  
Vol 62 (2) ◽  
pp. 135-147 ◽  
Author(s):  
Michael J. Cipriano ◽  
Stephen L. Hajduk
Keyword(s):  
Immune Responses ◽  
Extracellular Vesicles ◽  
Host Cells ◽  
Infected Host ◽  
Immune Recognition ◽  
Adhesive Properties ◽  
Host Immune Responses ◽  
Recognition And Response ◽  
And Function ◽  
Induced Changes

Extracellular vesicles (EVs) are produced by invading pathogens and also by host cells in response to infection. The origin, composition, and function of EVs made during infection are diverse and provide effective vehicles for localized and broad dissimilation of effector molecules in the infected host. Extracellular pathogens use EVs to communicate with each other by sensing the host environment contributing to social motility, tissue tropism, and persistence of infection. Pathogen-derived EVs can also interact with host cells to influence the adhesive properties of host membranes and to alter immune recognition and response. Intracellular pathogens can affect both the protein and RNA content of EVs produced by infected host cells. Release of pathogen-induced host EVs can affect host immune responses to infection. In this review, we will describe both the biogenesis and content of EVs produced by a number of diverse pathogens. In addition, we will examine the pathogen-induced changes to EVs produced by infected host cells.

scholarly journals Production of Eicosanoids and Other Oxylipins by Pathogenic Eukaryotic Microbes

2003 ◽  
Vol 16 (3) ◽  
pp. 517-533 ◽  
Author(s):  
Mairi C. Noverr ◽  
John R. Erb-Downward ◽  
Gary B. Huffnagle
Keyword(s):  
Immune Responses ◽  
Pathogenic Fungi ◽  
Host Cells ◽  
Chemokine Production ◽  
Host Immune Responses ◽  
Potential Link ◽  
Leukocyte Chemotaxis ◽  
Eukaryotic Microbes ◽  
Precise Role

SUMMARY Oxylipins are oxygenated metabolites of fatty acids. Eicosanoids are a subset of oxylipins and include the prostaglandins and leukotrienes, which are potent regulators of host immune responses. Host cells are one source of eicosanoids and oxylipins during infection; however, another potential source of eicosanoids is the pathogen itself. A broad range of pathogenic fungi, protozoa, and helminths produce eicosanoids and other oxylipins by novel synthesis pathways. Why do these organisms produce oxylipins? Accumulating data suggest that phase change and differentiation in these organisms are controlled by oxylipins, including prostaglandins and lipoxygenase products. The precise role of pathogen-derived eicosanoids in pathogenesis remains to be determined, but the potential link between pathogen eicosanoids and the development of TH2 responses in the host is intriguing. Mammalian prostaglandins and leukotrienes have been studied extensively, and these molecules can modulate Th1 versus Th2 immune responses, chemokine production, phagocytosis, lymphocyte proliferation, and leukocyte chemotaxis. Thus, eicosanoids and oxylipins (host or microbe) may be mediators of a direct host-pathogen “cross-talk” that promotes chronic infection and hypersensitivity disease, common features of infection by eukaryotic pathogens.

scholarly journals Ail Binding to Fibronectin Facilitates Yersinia pestis Binding to Host Cells and Yop Delivery

2010 ◽  
Vol 78 (8) ◽  
pp. 3358-3368 ◽  
Author(s):  
Tiffany M. Tsang ◽  
Suleyman Felek ◽  
Eric S. Krukonis
Keyword(s):  
Escherichia Coli ◽  
Extracellular Matrix ◽  
Immune Responses ◽  
Yersinia Pestis ◽  
Matrix Protein ◽  
Host Cells ◽  
Extracellular Matrix Protein ◽  
Cell Binding ◽  
E Coli ◽  
Host Immune Responses

ABSTRACT Yersinia pestis, the causative agent of plague, evades host immune responses and rapidly causes disease. The Y. pestis adhesin Ail mediates host cell binding and is critical for Yop delivery. To identify the Ail receptor(s), Ail was purified following overexpression in Escherichia coli. Ail bound specifically to fibronectin, an extracellular matrix protein with the potential to act as a bridge between Ail and host cells. Ail expressed by E. coli also mediated binding to purified fibronectin, and Ail-mediated E. coli adhesion to host cells was dependent on fibronectin. Ail expressed by Y. pestis bound purified fibronectin, as did the Y. pestis adhesin plasminogen activator (Pla). However, a KIM5 Δail mutant had decreased binding to host cells, while a KIM5 Δpla mutant had no significant defect in adhesion. Furthermore, treatment with antifibronectin antibodies decreased Ail-mediated adhesion by KIM5 and the KIM5 Δpla mutant, indicating that the Ail-fibronectin interaction was important for cell binding. Finally, antifibronectin antibodies inhibited the KIM5-mediated cytotoxicity of host cells in an Ail-dependent fashion. These data indicate that Ail is a key adhesin that mediates binding to host cells through interaction with fibronectin on the surface of host cells, and this interaction is important for Yop delivery by Y. pestis.

scholarly journals Singapore grouper iridovirus-encoded semaphorin homologue (SGIV-sema) contributes to viral replication, cytoskeleton reorganization and inhibition of cellular immune responses

2014 ◽  
Vol 95 (5) ◽  
pp. 1144-1155 ◽  
Author(s):  
Yang Yan ◽  
Huachun Cui ◽  
Chuanyu Guo ◽  
Jingguang Wei ◽  
Youhua Huang ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Replication ◽  
Host Cells ◽  
Early Gene ◽  
Coding Region ◽  
Cytoskeletal Structure ◽  
Wide Range ◽  
Fish Cells ◽  
Cellular Immune

Semaphorins are a large, phylogenetically conserved family of proteins that are involved in a wide range of biological processes including axonal steering, organogenesis, neoplastic transformation, as well as immune responses. In this study, a novel semaphorin homologue gene belonging to the Singapore grouper iridovirus (SGIV), ORF155R (termed SGIV-sema), was cloned and characterized. The coding region of SGIV-sema is 1728 bp in length, encoding a predicted protein with 575 aa. SGIV-sema contains a ~370 aa N-terminal Sema domain, a conserved plexin-semaphorin-integrin (PSI) domain, and an immunoglobulin (Ig)-like domain near the C terminus. SGIV-sema is an early gene product during viral infection and predominantly distributed in the cytoplasm with a speckled and clubbed pattern of appearance. Functionally, SGIV-sema could promote viral replication during SGIV infection in vitro, with no effect on the proliferation of host cells. Intriguingly, ectopically expressed SGIV-sema could alter the cytoskeletal structure of fish cells, characterized by a circumferential ring of microtubules near the nucleus and a disrupted microfilament organization. Furthermore, SGIV-sema was able to attenuate the cellular immune response, as demonstrated by decreased expression of inflammation/immune-related genes such as IL-8, IL-15, TNF-α and mediator of IRF3 activation (MITA), in SGIV-sema-expressing cells before and after SGIV infection. Ultimately, our study identified a novel, functional SGIV gene that could regulate cytoskeletal structure, immune responses and facilitate viral replication.

scholarly journals TICK SALIVA TOXINS, HOST IMMUNE RESPONSES AND ITS BIOLOGICAL EFFECTS

2021 ◽  
pp. 9-19
Author(s):  
NIDHI YADAV ◽  
RAVI KANT UPADHYAY
Keyword(s):  
Immune Responses ◽  
Biological Effects ◽  
Immune Therapy ◽  
Economic Losses ◽  
Tick Saliva ◽  
Tropical Regions ◽  
Terrestrial Vertebrates ◽  
Host Immune Responses ◽  
Blood Sucking ◽  
Wide Range

Ticks are the most important ancient group of obligate blood-sucking ectoparasites of terrestrial vertebrates mainly of livestock. These small-sized animals are found in tropical and sub-tropical regions of the world. These act as vectors and transmit a wide range of protozoa, bacteria and viruses tick-borne diseases. These attach to host skin for blood-sucking and transmit disease pathogens through saliva. Ticks withdraw large volumes of blood from livestock and make them anemic and do significant weight loss. Ticks cause severe economic losses in livestock directly through blood-feeding and indirectly by transmitting protozoan, rickettsial and viral diseases This article highlights toxins/proteins secreted in tick saliva, and its important biological effects like anti-inflammatory, immunosuppressant peptide, and immunomodulatory and anti-chemokine activities. The present article clears host-pathogen interactions and invasion of a host by ticks, biological effects of tick saliva toxins and its host immune responses. These toxins could be used as immunoreactive proteins as a prerequisite for the development of specific and sensitive immunoassays for the determination of tick-borne illness. The authors suggest important management strategies for successful control of cattle, bird and canine ticks. This article also suggests tick control methods such as physical, chemical, hormonal and including prophylactic use of antibody and vaccine immune therapy.

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