scholarly journals Indoleamine 2,3-Dioxygenase 1 Is a Lung-Specific Innate Immune Defense Mechanism That Inhibits Growth of Francisella tularensis Tryptophan Auxotrophs

2010 ◽  
Vol 78 (6) ◽  
pp. 2723-2733 ◽  
Author(s):  
Kaitian Peng ◽  
Denise M. Monack
Keyword(s):  
Francisella Tularensis ◽  
Defense Mechanisms ◽  
Defense Mechanism ◽  
Immune Defense ◽  
The Body ◽  
Innate Immune ◽  
Microbial Pathogens ◽  
Immune Mechanisms ◽  
Indoleamine 2,3 Dioxygenase ◽  
Organ Specific

ABSTRACT Upon microbial challenge, organs at various anatomic sites of the body employ different innate immune mechanisms to defend against potential infections. Accordingly, microbial pathogens evolved to subvert these organ-specific host immune mechanisms to survive and grow in infected organs. Francisella tularensis is a bacterium capable of infecting multiple organs and thus encounters a myriad of organ-specific defense mechanisms. This suggests that F. tularensis may possess specific factors that aid in evasion of these innate immune defenses. We carried out a microarray-based, negative-selection screen in an intranasal model of Francisella novicida infection to identify Francisella genes that contribute to bacterial growth specifically in the lungs of mice. Genes in the bacterial tryptophan biosynthetic pathway were identified as being important for F. novicida growth specifically in the lungs. In addition, a host tryptophan-catabolizing enzyme, indoleamine 2,3-dioxygenase 1 (IDO1), is induced specifically in the lungs of mice infected with F. novicida or Streptococcus pneumoniae. Furthermore, the attenuation of F. novicida tryptophan mutant bacteria was rescued in the lungs of IDO1−/− mice. IDO1 is a lung-specific innate immune mechanism that controls pulmonary Francisella infections.

scholarly journals Pattern Recognition Receptors and Cytokines inMycobacterium tuberculosisInfection—The Double-Edged Sword?

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Md. Murad Hossain ◽  
Mohd-Nor Norazmi
Keyword(s):  
Pattern Recognition ◽  
Innate Immunity ◽  
Defense Mechanisms ◽  
Defense Mechanism ◽  
Adaptive Immune Response ◽  
Protective Role ◽  
Pattern Recognition Receptors ◽  
Immune Defense ◽  
Innate Immune ◽  
Intercellular Adhesion Molecule

Tuberculosis, an infectious disease caused byMycobacterium tuberculosis(Mtb), remains a major cause of human death worldwide. Innate immunity provides host defense against Mtb. Phagocytosis, characterized by recognition of Mtb by macrophages and dendritic cells (DCs), is the first step of the innate immune defense mechanism. The recognition of Mtb is mediated by pattern recognition receptors (PRRs), expressed on innate immune cells, including toll-like receptors (TLRs), complement receptors, nucleotide oligomerization domain like receptors, dendritic cell-specific intercellular adhesion molecule grabbing nonintegrin (DC-SIGN), mannose receptors, CD14 receptors, scavenger receptors, and FCγreceptors. Interaction of mycobacterial ligands with PRRs leads macrophages and DCs to secrete selected cytokines, which in turn induce interferon-γ- (IFNγ-) dominated immunity. IFNγand other cytokines like tumor necrosis factor-α(TNFα) regulate mycobacterial growth, granuloma formation, and initiation of the adaptive immune response to Mtb and finally provide protection to the host. However, Mtb can evade destruction by antimicrobial defense mechanisms of the innate immune system as some components of the system may promote survival of the bacteria in these cells and facilitate pathogenesis. Thus, although innate immunity components generally play a protective role against Mtb, they may also facilitate Mtb survival. The involvement of selected PRRs and cytokines on these seemingly contradictory roles is discussed.

scholarly journals Cooperative Immune Suppression by Escherichia coli and Shigella Effector Proteins

2018 ◽  
Vol 86 (4) ◽  
Author(s):  
Maarten F. de Jong ◽  
Neal M. Alto
Keyword(s):  
Escherichia Coli ◽  
Defense Mechanisms ◽  
Immune Defense ◽  
Effector Proteins ◽  
Innate Immune ◽  
Host Cells ◽  
Secretion Systems ◽  
Content Type ◽  
E Coli ◽  
Type Iii Secretion Systems

ABSTRACT The enteric attaching and effacing (A/E) pathogens enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) and the invasive pathogens enteroinvasive E. coli (EIEC) and Shigella encode type III secretion systems (T3SS) used to inject effector proteins into human host cells during infection. Among these are a group of effectors required for NF-κB-mediated host immune evasion. Recent studies have identified several effector proteins from A/E pathogens and EIEC/ Shigella that are involved in suppression of NF-κB and have uncovered their cellular and molecular functions. A novel mechanism among these effectors from both groups of pathogens is to coordinate effector function during infection. This cooperativity among effector proteins explains how bacterial pathogens are able to effectively suppress innate immune defense mechanisms in response to diverse classes of immune receptor signaling complexes (RSCs) stimulated during infection.

Detection of Microbial Infections Through Innate Immune Sensing of Nucleic Acids

2018 ◽  
Vol 72 (1) ◽  
pp. 447-478 ◽  
Author(s):  
Xiaojun Tan ◽  
Lijun Sun ◽  
Jueqi Chen ◽  
Zhijian J. Chen
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Immune Defense ◽  
Innate Immune ◽  
Type I Interferons ◽  
Microbial Pathogens ◽  
Type I ◽  
Immune Recognition ◽  
Microbial Infection ◽  
Microbial Infections

Microbial infections are recognized by the innate immune system through germline-encoded pattern recognition receptors (PRRs). As most microbial pathogens contain DNA and/or RNA during their life cycle, nucleic acid sensing has evolved as an essential strategy for host innate immune defense. Pathogen-derived nucleic acids with distinct features are recognized by specific host PRRs localized in endolysosomes and the cytosol. Activation of these PRRs triggers signaling cascades that culminate in the production of type I interferons and proinflammatory cytokines, leading to induction of an antimicrobial state, activation of adaptive immunity, and eventual clearance of the infection. Here, we review recent progress in innate immune recognition of nucleic acids upon microbial infection, including pathways involving endosomal Toll-like receptors, cytosolic RNA sensors, and cytosolic DNA sensors. We also discuss the mechanisms by which infectious microbes counteract host nucleic acid sensing to evade immune surveillance.

scholarly journals Cnidarian Interaction with Microbial Communities: From Aid to Animal’s Health to Rejection Responses

Marine Drugs ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. 296 ◽  
Author(s):  
Loredana Stabili ◽  
Maria Parisi ◽  
Daniela Parrinello ◽  
Matteo Cammarata
Keyword(s):  
Microbial Communities ◽  
Environmental Changes ◽  
Defense Mechanism ◽  
Immune Defense ◽  
Innate Immune ◽  
Animal Disease ◽  
Normal Microbiota ◽  
Essential Components ◽  
Pathogenic Agents ◽  
And Behavior

The phylum Cnidaria is an ancient branch in the tree of metazoans. Several species exert a remarkable longevity, suggesting the existence of a developed and consistent defense mechanism of the innate immunity capable to overcome the potential repeated exposure to microbial pathogenic agents. Increasing evidence indicates that the innate immune system in Cnidarians is not only involved in the disruption of harmful microorganisms, but also is crucial in structuring tissue-associated microbial communities that are essential components of the Cnidarian holobiont and useful to the animal’s health for several functions, including metabolism, immune defense, development, and behavior. Sometimes, the shifts in the normal microbiota may be used as “early” bio-indicators of both environmental changes and/or animal disease. Here the Cnidarians relationships with microbial communities and the potential biotechnological applications are summarized and discussed.

scholarly journals Individual and social immune mechanisms of the honey bee (Apis mellifera)

2018 ◽  
Vol 74 (1) ◽  
pp. 6013-2018
Author(s):  
ANETA STRACHECKA ◽  
ALEKSANDRA ŁOŚ ◽  
JOANNA FILIPCZUK ◽  
MICHAŁ SCHULZ
Keyword(s):  
Apis Mellifera ◽  
Defense Mechanism ◽  
Resistance Mechanisms ◽  
The Body ◽  
Natural Resistance ◽  
Cell Mediated Immunity ◽  
Individual Level ◽  
Immune Mechanisms ◽  
Rebel Workers ◽  
The Individual

Honey bees (Apis mellifera) are constantly exposed to contact with many types of pathogens. However, during evolution they developed a number of immune mechanisms. At the individual level, they comprise 1) resistance mechanisms associated with anatomical and physiological barriers of the body, 2) cell-mediated immunity involving hemocytes (including plasmocytes, lamellocytes, and granulocytes), 3a) congenital humoral resistance related to the activity of lysozyme (N-acetylmuramylhydrolase), the prophenylooxidase system (ProPO) and hemagglutinins (lectins), and 3b) induced humoral resistence based on the action of antimicrobial peptides: apidicines, hymenoptecin, and defensins. In addition to the individual resistance of each bee, there is also a defense mechanism activated at the colony level. Shared secretion resistance is connected with the presence of antipathogenic compounds in secreta and in bee products. Social immunity is associated with hygienic and nursing behaviors, as well as with age polyethism in the colony, swarming (and the emergence of rebel workers), and the changing behavior of sick individuals. Many aspects and interactions between different types of resistance and immunity still remain unexplored. However, current research trends revolve around clarifying uncertainties so as to strengthen the natural resistance of bees and fight against pathogens that threaten the insects..

scholarly journals Redundant roles for inflammasome receptors NLRP3 and NLRC4 in host defense against Salmonella

2010 ◽  
Vol 207 (8) ◽  
pp. 1745-1755 ◽  
Author(s):  
Petr Broz ◽  
Kim Newton ◽  
Mohamed Lamkanfi ◽  
Sanjeev Mariathasan ◽  
Vishva M. Dixit ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Host Defense ◽  
Immune Defense ◽  
Innate Immune ◽  
Microbial Pathogens ◽  
Intracellular Pathogens ◽  
Danger Signals ◽  
Caspase 1 ◽  
Innate Immune Defense

Intracellular pathogens and endogenous danger signals in the cytosol engage NOD-like receptors (NLRs), which assemble inflammasome complexes to activate caspase-1 and promote the release of proinflammatory cytokines IL-1β and IL-18. However, the NLRs that respond to microbial pathogens in vivo are poorly defined. We show that the NLRs NLRP3 and NLRC4 both activate caspase-1 in response to Salmonella typhimurium. Responding to distinct bacterial triggers, NLRP3 and NLRC4 recruited ASC and caspase-1 into a single cytoplasmic focus, which served as the site of pro–IL-1β processing. Consistent with an important role for both NLRP3 and NLRC4 in innate immune defense against S. typhimurium, mice lacking both NLRs were markedly more susceptible to infection. These results reveal unexpected redundancy among NLRs in host defense against intracellular pathogens in vivo.

scholarly journals Plant Antimicrobial Peptides as Potential Anticancer Agents

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Jaquelina Julia Guzmán-Rodríguez ◽  
Alejandra Ochoa-Zarzosa ◽  
Rodolfo López-Gómez ◽  
Joel E. López-Meza
Keyword(s):  
Antimicrobial Peptides ◽  
Anticancer Agents ◽  
Pathogenic Bacteria ◽  
Defense Mechanism ◽  
Immune Defense ◽  
Innate Immune ◽  
High Morbidity ◽  
Anticancer Activities ◽  
Innate Immune Defense ◽  
Wide Range

Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms and are promising candidates to treat infections caused by pathogenic bacteria to animals and humans. AMPs also display anticancer activities because of their ability to inactivate a wide range of cancer cells. Cancer remains a cause of high morbidity and mortality worldwide. Therefore, the development of methods for its control is desirable. Attractive alternatives include plant AMP thionins, defensins, and cyclotides, which have anticancer activities. Here, we provide an overview of plant AMPs anticancer activities, with an emphasis on their mode of action, their selectivity, and their efficacy.

scholarly journals Innate Immune Defense Mechanisms by Myeloid Cells That Hamper Cancer Immunotherapy

2020 ◽  
Vol 11 ◽  
Author(s):  
Els Lebegge ◽  
Sana M. Arnouk ◽  
Pauline M. R. Bardet ◽  
Máté Kiss ◽  
Geert Raes ◽  
...  
Keyword(s):  
Cancer Immunotherapy ◽  
Defense Mechanisms ◽  
Myeloid Cells ◽  
Immune Defense ◽  
Innate Immune ◽  
Innate Immune Defense

scholarly journals COVID-19 Vaccines for HIV-Infected Patients

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1890
Author(s):  
Maria M. Plummer ◽  
Charles S. Pavia
Keyword(s):  
T Cells ◽  
Defense Mechanisms ◽  
Etiologic Agent ◽  
Immune Defense ◽  
Microbial Pathogens ◽  
Protective Measure ◽  
People Living With Hiv ◽  
Reverse Transcriptase Enzyme ◽  
Molecular Tests ◽  
Hiv Aids

Nearly 40 years have passed since the initial cases of infection with the human mmunodeficiency virus (HIV) were identified as a new disease entity and the cause of acquired immunodeficiency disease (AIDS). This virus, unlike any other, is capable of causing severe suppression of our adaptive immune defense mechanisms by directly infecting and destroying helper T cells leading to increased susceptibility to a wide variety of microbial pathogens, especially those considered to be intracellular or opportunistic. After T cells are infected, HIV reproduces itself via a somewhat unique mechanism involving various metabolic steps, which includes the use of a reverse transcriptase enzyme that enables the viral RNA to produce copies of its complementary DNA. Subsequent physiologic steps lead to the production of new virus progeny and the eventual death of the invaded T cell. Fortunately, both serologic and molecular tests (such as PCR) can be used to confirm the diagnosis of an HIV infection. In the wake of the current COVID-19 pandemic, it appears that people living with HIV/AIDS are equally or slightly more susceptible to the etiologic agent, SARS-CoV-2, than the general population having intact immune systems, but they may have more serious outcomes. Limited clinical trials have also shown that the currently available COVID-19 vaccines are both safe and effective in affording protection to HIV/AIDS patients. In this review, we further explore the unique dynamic of HIV/AIDS in the context of the worldwide COVID-19 pandemic and the implementation of vaccines as a protective measure against COVID-19, as well as what immune parameters and safeguards should be monitored in this immunocompromised group following vaccination.

scholarly journals A Debate on Vitamin C: Supplementation on the Hotline for COVID-19

2020 ◽  
Vol 11 (3) ◽  
pp. 395-396
Author(s):  
Ata Mahmoodpoor ◽  
Ali Shamekh ◽  
Sarvin Sanaie
Keyword(s):  
Vitamin C ◽  
Respiratory Distress ◽  
Innate Immune System ◽  
Defense Mechanisms ◽  
Distress Syndrome ◽  
Viral Disease ◽  
The Body ◽  
Innate Immune ◽  
Vitamin C Supplementation ◽  
Almost All

SARS-CoV-2 causes acute respiratory distress syndrome. As any other newly emerged viral disease, there are no definite and curative treatments available for the COVID-19 till now, so almost all of the available therapies are designed to support the body against the virus. A healthy and complete nutrition provides the resources to the body’s defense mechanisms. Vitamin C supplementation has shown promising results in the activation of the innate immune system and may protect against respiratory viral diseases. Here, we briefly discuss about its role in critically ill patients, respiratory distress, sepsis and possible role in COVID-19.

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