scholarly journals Host Innate Immunity Against Hepatitis Viruses and Viral Immune Evasion

2021 ◽  
Vol 12 ◽  
Author(s):  
Chonghui Xu ◽  
Jizheng Chen ◽  
Xinwen Chen
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Innate Immune System ◽  
Immune Surveillance ◽  
Innate Immune ◽  
Hepatitis Viruses ◽  
Specific Pathogen ◽  
Causative Agents ◽  
Immune Sensing

Hepatitis viruses are primary causative agents of hepatitis and represent a major source of public health problems in the world. The host innate immune system forms the first line of defense against hepatitis viruses. Hepatitis viruses are sensed by specific pathogen recognition receptors (PRRs) that subsequently trigger the innate immune response and interferon (IFN) production. However, hepatitis viruses evade host immune surveillance via multiple strategies, which help compromise the innate immune response and create a favorable environment for viral replication. Therefore, this article reviews published findings regarding host innate immune sensing and response against hepatitis viruses. Furthermore, we also focus on how hepatitis viruses abrogate the antiviral effects of the host innate immune system.

scholarly journals Insights into Innate Immune Response Against SARS-CoV-2 Infection

2021 ◽  
Vol 29 (3) ◽  
pp. 255-269
Author(s):  
Adina Huțanu ◽  
Anca Meda Georgescu ◽  
Akos Vince Andrejkovits ◽  
William Au ◽  
Minodora Dobreanu
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Innate Immune System ◽  
Time Course ◽  
Adaptive Immune Response ◽  
Innate Immune ◽  
Interferon Response ◽  
Humoral Factors ◽  
Key Steps

Abstract The innate immune system is mandatory for the activation of antiviral host defense and eradication of the infection. In this regard, dendritic cells, natural killer cells, macrophages, neutrophils representing the cellular component, and cytokines, interferons, complement or Toll-Like Receptors, representing the mediators of unspecific response act together for both activation of the adaptive immune response and viral clearance. Of great importance is the proper functioning of the innate immune response from the very beginning. For instance, in the early stages of viral infection, the defective interferon response leads to uncontrolled viral replication and pathogen evasion, while hypersecretion during the later stages of infection generates hyperinflammation. This cascade activation of systemic inflammation culminates with cytokine storm syndrome and hypercoagulability state, due to a close interconnection between them. Thus an unbalanced reaction, either under- or over- stimulation of the innate immune system will lead to an uncoordinated response and unfavorable disease outcomes. Since both cellular and humoral factors are involved in the time-course of the innate immune response, in this review we aimed to address their gradual involvement in the antiviral response with emphasis on key steps in SARS-CoV-2 infection.

The role of the innate immune system on pulmonary infections

2019 ◽  
Vol 400 (4) ◽  
pp. 443-456 ◽  
Author(s):  
Michelle Galeas-Pena ◽  
Nathaniel McLaughlin ◽  
Derek Pociask
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Innate Immune System ◽  
Adaptive Immune System ◽  
Innate Immune ◽  
Resistant Bacteria ◽  
Upper Respiratory Tract ◽  
Phagocytic Cells ◽  
Mucus Production

Abstract Inhalation is required for respiration and life in all vertebrates. This process is not without risk, as it potentially exposes the host to environmental pathogens with every breath. This makes the upper respiratory tract one of the most common routes of infection and one of the leading causes of morbidity and mortality in the world. To combat this, the lung relies on the innate immune defenses. In contrast to the adaptive immune system, the innate immune system does not require sensitization, previous exposure or priming to attack foreign particles. In the lung, the innate immune response starts with the epithelial barrier and mucus production and is reinforced by phagocytic cells and T cells. These cells are vital for the production of cytokines, chemokines and anti-microbial peptides that are critical for clearance of infectious agents. In this review, we discuss all aspects of the innate immune response, with a special emphasis on ways to target aspects of the immune response to combat antibiotic resistant bacteria.

scholarly journals Modeling Virus-Induced Inflammation in Zebrafish: A Balance Between Infection Control and Excessive Inflammation

2021 ◽  
Vol 12 ◽  
Author(s):  
Con Sullivan ◽  
Brandy-Lee Soos ◽  
Paul J. Millard ◽  
Carol H. Kim ◽  
Benjamin L. King
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Inflammatory Response ◽  
Viral Infection ◽  
Innate Immune Response ◽  
Innate Immune System ◽  
Innate Immune ◽  
Zebrafish Model ◽  
Infection Models

The inflammatory response to viral infection in humans is a dynamic process with complex cell interactions that are governed by the immune system and influenced by both host and viral factors. Due to this complexity, the relative contributions of the virus and host factors are best studied in vivo using animal models. In this review, we describe how the zebrafish (Danio rerio) has been used as a powerful model to study host-virus interactions and inflammation by combining robust forward and reverse genetic tools with in vivo imaging of transparent embryos and larvae. The innate immune system has an essential role in the initial inflammatory response to viral infection. Focused studies of the innate immune response to viral infection are possible using the zebrafish model as there is a 4-6 week timeframe during development where they have a functional innate immune system dominated by neutrophils and macrophages. During this timeframe, zebrafish lack a functional adaptive immune system, so it is possible to study the innate immune response in isolation. Sequencing of the zebrafish genome has revealed significant genetic conservation with the human genome, and multiple studies have revealed both functional conservation of genes, including those critical to host cell infection and host cell inflammatory response. In addition to studying several fish viruses, zebrafish infection models have been developed for several human viruses, including influenza A, noroviruses, chikungunya, Zika, dengue, herpes simplex virus type 1, Sindbis, and hepatitis C virus. The development of these diverse viral infection models, coupled with the inherent strengths of the zebrafish model, particularly as it relates to our understanding of macrophage and neutrophil biology, offers opportunities for far more intensive studies aimed at understanding conserved host responses to viral infection. In this context, we review aspects relating to the evolution of innate immunity, including the evolution of viral pattern recognition receptors, interferons and interferon receptors, and non-coding RNAs.

scholarly journals How the Innate Immune System Fights for Your Health

2021 ◽  
Vol 9 ◽  
Author(s):  
Mieke C. Louwe ◽  
Pål Aukrust
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Innate Immune System ◽  
The Body ◽  
Innate Immune ◽  
Response Activation

When your body encounters intruders like viruses, bacteria, fungi, or parasites, this invasion triggers a complex and amazing process called the immune response. Activation of the body’s immune system is necessary to fight off these intruders, but it must also distinguish them from the body’s own healthy tissues. The goal of the immune response is to keep the body healthy. The earliest responses that occur to protect the body from invading organisms is called the innate immune response. In this article, we explain the components of the innate immune system and how this system helps to keep the body safe from dangerous invaders.

The C-terminal domain of Salmonid Alphavirus nonstructural protein 2 (nsP2) is essential and sufficient to block RIG-I pathway induction and interferon-mediated antiviral response.

2021 ◽  
Author(s):  
Raphaël Jami ◽  
Emilie Mérour ◽  
Julie Bernard ◽  
Annie Lamoureux ◽  
Jean K. Millet ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Nuclear Localization ◽  
Innate Immune ◽  
Type I ◽  
Annual Growth Rate ◽  
Structural Protein ◽  
Terminal Domain ◽  
Nuclear Localization Sequences

Salmonid alphavirus (SAV) is an atypical alphavirus, which has a considerable impact on salmon and trout farms. Unlike other alphaviruses such as the chikungunya virus, SAV is transmitted without an arthropod vector, and does not cause cell shut-off during infection. The mechanisms by which SAV escapes the host immune system remain unknown. By studying the role of SAV proteins on the RIG-I signaling cascade, the first line of defense of the immune system during infection, we demonstrated that non-structural protein 2 (nsP2) effectively blocks the induction of type I interferon (IFN). This inhibition, independent of the protease activity carried by nsP2, occurs downstream of IRF3 which is the transcription factor allowing the activation of the IFN promoter and its expression. The inhibitory effect of nsP2 on the RIG-I pathway depends on the localization of nsP2 in the host cell nucleus which is linked to two nuclear localization sequences (NLS) located in its C-terminal part. The C-terminal domain of nsP2 by itself is sufficient and necessary to block IFN induction. Mutation of the NLS of nsP2 is deleterious to the virus. Finally, nsP2 does not interact with IRF3, indicating that its action is possible through a targeted interaction within discrete areas of chromatin, as suggested by its punctate distribution observed in the nucleus. These results therefore demonstrate a major role for nsP2 in the control by SAV of the host cell’s innate immune response. Importance The global consumption of fish continues to rise and the future demand cannot be met by capture fisheries alone due to limited stocks of wild fish. Aquaculture is currently the world’s fastest growing food production sector with an annual growth rate of 6-8 %. Recurrent outbreaks of SAV result in significant economic losses with serious environmental consequences on wild stocks. While the clinical and pathological signs of SAV infection are fairly well known, the molecular mechanisms involved are poorly described. In the present study, we focus on the non-structural protein nsP2 and characterize a specific domain containing nuclear localization sequences that are critical for the inhibition of the host innate immune response mediated by the RIG-I pathway.

2. First responders: the innate immune response

2017 ◽  
pp. 17-29
Author(s):  
Paul Klenerman
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Acute Phase Response ◽  
First Responders ◽  
Fundamental Question ◽  
Innate Immune ◽  
Rapid Action ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

How does the immune system know when to respond? ‘First responders: the innate immune response’ considers this fundamental question that is central to understanding both normal (e.g. to infections) and abnormal (e.g. in auto-immune diseases) responses; and designing vaccines and new therapies in cancer and infectious diseases. It looks at how ‘danger’ is sensed by the immune system through pathogen-associated molecular patterns and damage-associated molecular patterns. Having been alerted, it is important that rapid action is taken to limit the spread of a pathogen. A number of responses can be initiated immediately, forming a critical part of our innate immunity, which are followed by the acute phase response.

scholarly journals Insights into Sensing of Murine Retroviruses

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 836
Author(s):  
Eileen A. Moran ◽  
Susan R. Ross
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Nucleic Acid ◽  
Adaptive Immunity ◽  
Innate Immune System ◽  
Innate Immune ◽  
Genetic Tool ◽  
Causes Of Disease ◽  
Retrovirus Infection ◽  
Insight Into

Retroviruses are major causes of disease in animals and human. Better understanding of the initial host immune response to these viruses could provide insight into how to limit infection. Mouse retroviruses that are endemic in their hosts provide an important genetic tool to dissect the different arms of the innate immune system that recognize retroviruses as foreign. Here, we review what is known about the major branches of the innate immune system that respond to mouse retrovirus infection, Toll-like receptors and nucleic acid sensors, and discuss the importance of these responses in activating adaptive immunity and controlling infection.

scholarly journals Phenoloxidase activity and haemolymph cytology in honeybees challenged with a virus suspension (deformed wings virus DWV) or phosphate buffered suspension (PBS)

2019 ◽  
Vol 49 (2) ◽  
Author(s):  
Francesca Millanta ◽  
Simona Sagona ◽  
Maurizio Mazzei ◽  
Mario Forzan ◽  
Alessandro Poli ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Immune Responses ◽  
Innate Immune System ◽  
Innate Immune ◽  
Additional Stress ◽  
Varroa Mite ◽  
Virus Suspension ◽  
Phenoloxidase Activity ◽  
Cell Immunity

ABSTRACT: The innate immune system of honeybees mainly consists in antimicrobial peptides, cellular immunity and melanisation. In order to investigate the immune response of honeybees to immune stressors, three stress degrees were tested. Newly emerged bees naturally DWV-infected were collected from a Varroa mite-free apiary and divided into three experimental groups: naturally DWV infected bees, PBS injected bees, and artificially DWV super infected bees. Phenoloxidase activity and haemolymph cellular subtype count were investigated. Phenoloxidase activity was highest (P<0.05) in DWV-superinfected bees, and the haemocyte population differed within the three observed groups. Although, immune responses following DWV infection have still not been completely clarified, this investigation sheds light on the relation between cell immunity and the phenoloxidase activity of DWV-naturally infected honeybees exposed to additional stress such as injury and viral superinfection.

scholarly journals P53 and The Immune Response: 40 Years of Exploration—A Plan for the Future

2020 ◽  
Vol 21 (2) ◽  
pp. 541 ◽  
Author(s):  
Arnold J. Levine
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune System ◽  
P53 Protein ◽  
P53 Gene ◽  
T Cell Response ◽  
Innate Immune ◽  
Transplantation Antigen ◽  
Mutant Form ◽  
The Future

The p53 field was born from a marriage of the techniques of cancer virus research and immunology. Over the past 40 years, it has followed the path of cancer research. Now cancer treatments are turning to immunotherapy, and there are many hints of the role of the p53 protein in both the regulation of the innate immune system and as an antigen in adaptive immune responses. The p53 gene and protein are part of the innate immune system, and play an important role in infectious diseases, senescence, aging, and the surveillance of repetitive DNA and RNAs. The mutant form of the p53 protein in cancers elicits both a B-cell antibody response (a tumor antigen) and a CD-8 killer T-cell response (a tumor-specific transplantation antigen). The future will take the p53-immune response field of research into cancer immunotherapy, autoimmunity, inflammatory responses, neuro-degeneration, aging, and life span, and the regulation of epigenetic stability and tissue regeneration. The next 40 years will bring the p53 gene and its proteins out of a cancer focus and into an organismic and environmental focus.

scholarly journals Determination of the Role and Active Sites of PKC-Delta-Like from Lamprey in Innate Immunity

2019 ◽  
Vol 20 (13) ◽  
pp. 3357
Author(s):  
Yang Xu ◽  
Huan Zhao ◽  
Yang Tian ◽  
Kaixia Ren ◽  
Nan Zheng ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Immune System ◽  
Innate Immune Response ◽  
Active Sites ◽  
Innate Immune ◽  
Pkc Delta ◽  
Kinase C ◽  
Catalytic Fragment

Protein kinase C-δ (PKC-δ) is an important protein in the immune system of higher vertebrates. Lampreys, as the most primitive vertebrates, have a uniquevariable lymphocyte receptor (VLR) immune system. PKC-δ-like is a crucial functional gene in lampreys and is highly expressed in their immune organs. In this study, lampreys were stimulated with different immunogens, and lipopolysaccharide (LPS) was found to increase the expression of PKC-δ-like. Overexpression of PKC-δ-like could also effectively activate the innate immune response. We further demonstrated that PKC-δ-like-CF, a catalytic fragment of PKC-δ-like, is responsible for activating the innate immune response, and Thr-211, which is Thr-419 of PKC-δ-like, was confirmed to be the key site affecting PKC-δ-like-CF activity. These results indicated that PKC-δ-like from lamprey may have an important role in the innate immune response.

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