scholarly journals Innate Immune Recognition: Implications for the Interaction of Francisella tularensis with the Host Immune System

2017 ◽  
Vol 7 ◽  
Author(s):  
Zuzana Krocova ◽  
Ales Macela ◽  
Klara Kubelkova
Keyword(s):  
Immune System ◽  
Francisella Tularensis ◽  
Innate Immune ◽  
Host Immune System ◽  
Immune Recognition

scholarly journals CD46 Plays a Key Role in Tailoring Innate Immune Recognition of Apoptotic and Necrotic Cells

2005 ◽  
Vol 280 (43) ◽  
pp. 36342-36354 ◽  
Author(s):  
Kristina Elward ◽  
Mark Griffiths ◽  
Masashi Mizuno ◽  
Claire L. Harris ◽  
Jim W. Neal ◽  
...  
Keyword(s):  
Immune System ◽  
Innate Immune System ◽  
Apoptotic Cell ◽  
Membrane Attack Complex ◽  
Factor H ◽  
Innate Immune ◽  
Immune Recognition ◽  
Alternative Pathways ◽  
Complement Regulator ◽  
Complement C1q

Complement is the canonical innate immune system involved in host defense and tissue repair with the clearance of cell debris. In contrast to the robust armory mounted against microbial nonself-pathogens, complement is selectively activated on altered self (i.e. apoptotic and necrotic cells) to instruct the safe demise by poorly characterized mechanisms. Our data shed new light on the role of complement C1q in sensing nucleic acids (NA) rapidly exposed on apoptotic Jurkat T cell membranes and in driving C3 opsonization but without the lytic membrane attack complex. DNA/RNase-treated apoptotic cells failed to activate complement. We found that several other apoptotic cell models, including senescent keratinocytes, ionophore-treated sperm cells, and CMK-derived platelets, stained for cleaved caspase 3 were rapidly losing the key complement regulator CD46. CD46 from nuclear and membrane stores was found to cluster into blebs and shed into microparticles together with NA, phosphatidylserine, C1q, and factor H. Classical and alternative pathways of complement were involved in the recognition of H2O2-treated necrotic cells. Membrane attack complex was detected on necrotic cells possibly as a result of CD46 and CD59 shedding into soluble forms. Our data highlight a novel and universal paradigm whereby the complement innate immune system is using two synergistic strategies with the recognition of altered self-NA and missing self-CD46 signals to instruct and tailor the efficient removal of apoptotic and necrotic cells in immunoprivileged sites.

scholarly journals The Interplay between Host Innate Immunity and Hepatitis E Virus

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 541 ◽  
Author(s):  
Yang Li ◽  
Changbo Qu ◽  
Peifa Yu ◽  
Xumin Ou ◽  
Qiuwei Pan ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune System ◽  
Hepatitis E Virus ◽  
Inflammatory Responses ◽  
Hepatitis E ◽  
Experimental Models ◽  
Innate Immune ◽  
Host Immune System ◽  
Global Health Issue ◽  
Host Innate Immunity

Hepatitis E virus (HEV) infection represents an emerging global health issue, whereas the clinical outcomes vary dramatically among different populations. The host innate immune system provides a first-line defense against the infection, but dysregulation may partially contribute to severe pathogenesis. A growing body of evidence has indicated the active response of the host innate immunity to HEV infection both in experimental models and in patients. In turn, HEV has developed sophisticated strategies to counteract the host immune system. In this review, we aim to comprehensively decipher the processes of pathogen recognition, interferon, and inflammatory responses, and the involvement of innate immune cells in HEV infection. We further discuss their implications in understanding the pathogenic mechanisms and developing antiviral therapies.

scholarly journals Peptidoglycan O-Acetylation as a Virulence Factor: Its Effect on Lysozyme in the Innate Immune System

Antibiotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 94 ◽  
Author(s):  
Ashley S. Brott ◽  
Anthony J. Clarke
Keyword(s):  
Immune System ◽  
Virulence Factor ◽  
Innate Immune System ◽  
Innate Immune ◽  
Host Immune System ◽  
Gram Negative Bacteria ◽  
First Line ◽  
Structural Support ◽  
Important Virulence Factor ◽  
Novel Target

The peptidoglycan sacculus of both Gram-positive and Gram-negative bacteria acts as a protective mesh and provides structural support around the entirety of the cell. The integrity of this structure is of utmost importance for cell viability and so naturally is the first target for attack by the host immune system during bacterial infection. Lysozyme, a muramidase and the first line of defense of the innate immune system, targets the peptidoglycan sacculus hydrolyzing the β-(1→4) linkage between repeating glycan units, causing lysis and the death of the invading bacterium. The O-acetylation of N-acetylmuramoyl residues within peptidoglycan precludes the productive binding of lysozyme, and in doing so renders it inactive. This modification has been shown to be an important virulence factor in pathogens such as Staphylococcus aureus and Neisseria gonorrhoeae and is currently being investigated as a novel target for anti-virulence therapies. This article reviews interactions made between peptidoglycan and the host immune system, specifically with respect to lysozyme, and how the O-acetylation of the peptidoglycan interrupts these interactions, leading to increased pathogenicity.

scholarly journals Bacterial lipids: powerful modifiers of the innate immune response

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1334 ◽  
Author(s):  
Courtney E. Chandler ◽  
Robert K. Ernst
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Lipoteichoic Acid ◽  
Innate Immune ◽  
Microbial Pathogens ◽  
Host Immune System ◽  
Receptor Proteins ◽  
Bacterial Membranes ◽  
Host Innate Immune Response

The innate immune system serves as a first line of defense against microbial pathogens. The host innate immune response can be triggered by recognition of conserved non-self-microbial signature molecules by specific host receptor proteins called Toll-like receptors. For bacteria, many of these molecular triggers reside on or are embedded in the bacterial membrane, the interface exposed to the host environment. Lipids are the most abundant component of membranes, and bacteria possess a unique set of lipids that can initiate or modify the host innate immune response. Bacterial lipoproteins, peptidoglycan, and outer membrane molecules lipoteichoic acid and lipopolysaccharide are key modulators of the host immune system. This review article will highlight some of the research emerging at the crossroads of bacterial membranes and innate immunity.

Leishmanial apolipoprotein A-I expression: a possible strategy used by the parasite to evade the host’s immune response

2021 ◽  
Author(s):  
Kurosh Kalantar ◽  
Raúl Manzano-Román ◽  
Esmaeel Ghani ◽  
Reza Mansouri ◽  
Gholamreza Hatam ◽  
...  
Keyword(s):  
Immune System ◽  
Molecular Mimicry ◽  
Innate Immune ◽  
Host Immune System ◽  
Innate Immune Responses ◽  
Multiple Strategies ◽  
Apolipoprotein A ◽  
Trypanosome Lytic Factor ◽  
Main Component ◽  
Leishmania Parasites

Apolipoprotein A-I (apo A-I) represents the main component of the Trypanosome lytic factor (TLF) which contributes to the host innate immunity against Trypanosoma and Leishmania. These parasites use complex and multiple strategies such as molecular mimicry to evade or subvert the host immune system. Previous studies have highlighted the adaptation mechanisms of TLF-resistant Trypanosoma species. These data might support the hypothesis that Leishmania parasites (amastigote forms in macrophages) might express apo A-I to bypass and escape from TLF action as a component of the host innate immune responses. The anti-inflammatory property of apo A-I is another mechanism that supports our idea that apo A-I may play a role in Leishmania parasites allowing them to bypass the host innate immune system.

Changes of Lymphocyte Subsets in Pulmonary Tuberculosis

2021 ◽  
Author(s):  
Hao Feng ◽  
Xue Yang
Keyword(s):  
Immune System ◽  
B Cells ◽  
Pulmonary Tuberculosis ◽  
Defense Mechanism ◽  
Positive Control ◽  
Community Acquired Pneumonia ◽  
Innate Immune ◽  
Host Immune System ◽  
Cd8 Cells ◽  
Pathogen Elimination

Abstract Background and AimsThe host immune system plays an important role in the pathogenesis and defense mechanism of Mycobacterium tuberculosis (Mtb). This study aimed to explore the changes of immune system in Pulmonary Tuberculosis (PTB) patients.MethodsA total of 85 active PTB patients and 50 healthy adults were enrolled, fifty patients with community-acquired pneumonia (CAP) were enrolled as the positive control. Chest CT and lymphocyte subgroup counts in peripheral blood were measured in all participants.ResultsIn the PTB group, the level of CD4 + and B cells and the ratio of CD4+/CD8 + cells were significantly increased, the frequency of NK cells was significantly decreased at the same time.ConclusionsThe manifestation of immune system was changed in PTB patients, the inflammation in the infected lesion was limited which decreased innate immune activation, and the increased of T and B cells responses as the main pathogen elimination method.

scholarly journals Glances in Immunology of HIV and HCV Infection

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Maria Giovanna Quaranta ◽  
Benedetta Mattioli ◽  
Stefano Vella
Keyword(s):  
Immune System ◽  
Immune Escape ◽  
Current Knowledge ◽  
Research Field ◽  
New Drugs ◽  
Host Immune System ◽  
Immune Recognition ◽  
Genetic Associations ◽  
Efficient Treatment ◽  
Adaptive Immune

Since the identification of HIV and HCV much progress has been made in the understanding of their life cycle and interaction with the host immune system. Despite these viruses markedly differ in their virological properties and in their pathogenesis, they share many common features in their immune escape and survival strategy. Both viruses have developed sophisticated ways to subvert and antagonize host innate and adaptive immune responses. In the last years, much effort has been done in the study of the AIDS pathogenesis and in the development of efficient treatment strategies, and a fatal infection has been transformed in a potentially chronic pathology. Much of this knowledge is now being transferred in the HCV research field, especially in the development of new drugs, although a big difference still remains between the outcome of the two infections, being HCV eradicable after treatment, whereas HIV eradication remains at present unachievable due to the establishment of reservoirs. In this review, we present current knowledge on innate and adaptive immune recognition and activation during HIV and HCV mono-infections and evasion strategies. We also discuss the genetic associations between components of the immune system, the course of infection, and the outcome of the therapies.

scholarly journals Viral Modulation of TLRs and Cytokines and the Related Immunotherapies for HPV-Associated Cancers

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Marconi Rego Barros ◽  
Talita Helena Araújo de Oliveira ◽  
Cristiane Moutinho Lagos de Melo ◽  
Aldo Venuti ◽  
Antonio Carlos de Freitas
Keyword(s):  
Immune Response ◽  
Human Papillomavirus ◽  
Immune System ◽  
Immune Evasion ◽  
Innate Immune System ◽  
Innate Immune ◽  
Cell Maturation ◽  
Host Immune System ◽  
Key Factor ◽  
Infected Cells

The modulation of the host innate immune system is a well-established carcinogenesis feature of several tumors, including human papillomavirus- (HPV-) related cancers. This virus is able to interrupt the initial events of the immune response, including the expression of Toll-like receptors (TLRs), cytokines, and inflammation. Both TLRs and cytokines play a central role in HPV recognition, cell maturation and differentiation as well as immune signalling. Therefore, the imbalance of this sensitive control of the immune response is a key factor for developing immunotherapies, which strengthen the host immune system to accomplish an efficient defence against HPV and HPV-infected cells. Based on this, the review is aimed at exposing the HPV immune evasion mechanisms involving TLRs and cytokines and at discussing existing and potential immunotherapeutic TLR- and cytokine-related tools.

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