scholarly journals Emerging Role of PYHIN Proteins as Antiviral Restriction Factors

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1464
Author(s):  
Matteo Bosso ◽  
Frank Kirchhoff
Keyword(s):  
Viral Infections ◽  
Specific Pattern ◽  
Immune Defense ◽  
Innate Immune ◽  
Cellular Proteins ◽  
Restriction Factors ◽  
First Line ◽  
Viral Pathogens ◽  
Molecular Patterns

Innate immune sensors and restriction factors are cellular proteins that synergize to build an effective first line of defense against viral infections. Innate sensors are usually constitutively expressed and capable of detecting pathogen-associated molecular patterns (PAMPs) via specific pattern recognition receptors (PRRs) to stimulate the immune response. Restriction factors are frequently upregulated by interferons (IFNs) and may inhibit viral pathogens at essentially any stage of their replication cycle. Members of the Pyrin and hematopoietic interferon-inducible nuclear (HIN) domain (PYHIN) family have initially been recognized as important sensors of foreign nucleic acids and activators of the inflammasome and the IFN response. Accumulating evidence shows, however, that at least three of the four members of the human PYHIN family restrict viral pathogens independently of viral sensing and innate immune activation. In this review, we provide an overview on the role of human PYHIN proteins in the innate antiviral immune defense and on viral countermeasures.

scholarly journals Cellular Responses to Cytosolic Double-stranded RNA–-The Role of the Inflammasome

2014 ◽  
Vol 6 ◽  
pp. III.S17839 ◽  
Author(s):  
Adi Idris
Keyword(s):  
Innate Immune System ◽  
Viral Infections ◽  
Cellular Responses ◽  
Specific Pattern ◽  
Innate Immune ◽  
Host Cells ◽  
Virus Infected Cell ◽  
Double Stranded Rna ◽  
Molecular Patterns

Sensing the presence of a pathogen is an evolutionarily ancient trait, especially for cells of the innate immune system. The innate immune response against pathogens, such as viruses, begins with recognition of pathogen-associated molecular patterns (PAMPs) by specific pattern-recognition receptors (PRRs). Cytosolic double-stranded RNA (dsRNA) is emerging as a critical PAMP in the detection of viral infections. This recognition results in the production of antiviral and proinflammatory cytokines and, often, the death of the virus-infected cell. This review focuses on the current developments in the role of inflammasomes in response to the presence of cytosolic dsRNA in host cells. More importantly, it highlights important unanswered questions that if addressed will help us better understand the ways in which host cells respond to viral infection, in particular RNA viruses.

scholarly journals Neutrophils—From Bone Marrow to First-Line Defense of the Innate Immune System

2021 ◽  
Vol 12 ◽  
Author(s):  
Richard Felix Kraus ◽  
Michael Andreas Gruber
Keyword(s):  
Immune System ◽  
Innate Immune System ◽  
Current Knowledge ◽  
Immune Defense ◽  
Innate Immune ◽  
Human Organism ◽  
Polymorphonuclear Cells ◽  
Target Tissue ◽  
First Line

Neutrophils (polymorphonuclear cells; PMNs) form a first line of defense against pathogens and are therefore an important component of the innate immune response. As a result of poorly controlled activation, however, PMNs can also mediate tissue damage in numerous diseases, often by increasing tissue inflammation and injury. According to current knowledge, PMNs are not only part of the pathogenesis of infectious and autoimmune diseases but also of conditions with disturbed tissue homeostasis such as trauma and shock. Scientific advances in the past two decades have changed the role of neutrophils from that of solely immune defense cells to cells that are responsible for the general integrity of the body, even in the absence of pathogens. To better understand PMN function in the human organism, our review outlines the role of PMNs within the innate immune system. This review provides an overview of the migration of PMNs from the vascular compartment to the target tissue as well as their chemotactic processes and illuminates crucial neutrophil immune properties at the site of the lesion. The review is focused on the formation of chemotactic gradients in interaction with the extracellular matrix (ECM) and the influence of the ECM on PMN function. In addition, our review summarizes current knowledge about the phenomenon of bidirectional and reverse PMN migration, neutrophil microtubules, and the microtubule organizing center in PMN migration. As a conclusive feature, we review and discuss new findings about neutrophil behavior in cancer environment and tumor tissue.

Natural killer cell in the developing life

2015 ◽  
Vol 43 (1) ◽  
Author(s):  
Yen-Chang Lee ◽  
Syh-Jae Lin
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Immune Cells ◽  
Killer Cell ◽  
Immune Defense ◽  
Innate Immune ◽  
First Line ◽  
Successful Pregnancy ◽  
Neonatal Stage

AbstractNatural killer (NK) cells that provide first-line innate immune reactions against virus-infected and tumor cells have different roles in different body sites and in different stages. From the beginning of life, NK cells participate in many aspects of development, especially in a successful pregnancy and a healthy neonatal stage. This article reviews recent advances regarding the role of NK cells in implantation, placentation and immune tolerance during pregnancy as well as in the neonatal immune defense. The interactions between NK cells and other immune cells in each developmental stage are discussed.

scholarly journals In Vivo Imaging of Neutrophil Extracellular Traps (NETs): Visualization Methods and Outcomes

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Sultan Z. Alasmari
Keyword(s):  
Neutrophil Extracellular Traps ◽  
Immune Defense ◽  
Innate Immune ◽  
First Line ◽  
The Third ◽  
Extracellular Traps ◽  
Host Pathogen Interaction ◽  
Unique Method

Neutrophils comprise the first line of innate immune defense during a host-pathogen interaction. They attack microorganisms directly through three different methods, of which, phagocytosis and degranulation have been known and well-studied for decades. The formation of neutrophil extracellular traps (NETs) is the third and unique method, which was unveiled in 2004. Since then, many studies on NETs have been carried out. However, only few have successfully demonstrated the activity of NETs in vivo. Results of the in vivo studies on NETs have strengthened our understanding of their role in different situations. This review highlights the main in vivo studies, which have contributed in extending our understanding of the role of NETs during infections and diseases, thus indicating their advantages and limitations.

scholarly journals Role of Toll-Like Receptors in Activation of Porcine Alveolar Macrophages by Porcine Reproductive and Respiratory Syndrome Virus

2009 ◽  
Vol 16 (3) ◽  
pp. 360-365 ◽  
Author(s):  
Laura C. Miller ◽  
Kelly M. Lager ◽  
Marcus E. Kehrli
Keyword(s):  
Alveolar Macrophages ◽  
Viral Infections ◽  
Rna Virus ◽  
Innate Immune ◽  
Respiratory Syndrome Virus ◽  
Double Stranded Rna ◽  
Tlr4 Activation ◽  
Molecular Patterns ◽  
Rapid Activation

ABSTRACT Control of virus replication initially depends on rapid activation of the innate immune response. Toll-like receptor (TLR) ligands are potent inducers of innate immunity against viral infections. Porcine reproductive and respiratory syndrome virus (PRRSV), a positive-sense RNA virus, initiates infection in porcine alveolar macrophages (PAMs), elicits weak immune responses, and establishes a persistent infection. To understand the role of single-stranded RNA and double-stranded RNA (dsRNA) intermediates in eliciting host immunity, we sought to determine if TLRs, particularly those that respond to viral molecular patterns, are involved in PRRSV infection. Activation of TLR3 in PAMs with dsRNA increased gene expression for alpha interferon and suppressed PRRSV infectivity. In contrast, TLR4 activation by the treatment of PAMs with lipopolysaccharide did not influence PRRSV infectivity.

scholarly journals Prevailing role of mucosal immunoglobulins and B cells in teleost skin immune responses to bacterial infection

2020 ◽  
Author(s):  
Xiao-Ting Zhang ◽  
Yong-Yao Yu ◽  
Hao-Yue Xu ◽  
Zhen-Yu Huang ◽  
Xia Liu ◽  
...  
Keyword(s):  
B Cells ◽  
Bacterial Infection ◽  
Inflammatory Responses ◽  
The Body ◽  
Innate Immune ◽  
Flavobacterium Columnare ◽  
First Line ◽  
Skin Mucus ◽  
Skin Mucosa

AbstractThe skin of vertebrates is the outermost organ of the body and serves as the first line of defense against external aggressions. In contrast to mammalian skin, that of teleost fish lacks keratinization and has evolved to operate as a mucosal surface containing a skin-associated lymphoid tissue (SALT). Thus far, IgT representing the prevalent immunoglobulin (Ig) in SALT have only been reported upon infection with a parasite. However, very little is known about the types of B cells and Igs responding to bacterial infection in the teleost skin mucosa, as well as the inductive or effector role of the SALT in such responses. To address these questions, here we analyzed the immune response of trout skin upon infection with one of the most widespread fish skin bacterial pathogens, Flavobacterium columnare. This pathogen induced strong skin innate immune and inflammatory responses at the initial phases of infection. More critically, we found that the skin mucus of fish having survived the infection contained significant IgT-but not IgM- or IgD-specific titers against the bacteria. Moreover, we demonstrate the local proliferation and production of IgT+ B-cells and specific IgT titers respectively within the SALT upon bacterial infection. Thus, our findings represent the first demonstration that IgT is the main Ig isotype induced by the skin mucosa upon bacterial infection, and that because of the large surface of the skin, its SALT probably represents a prominent IgT inductive site in fish.

Aids-Associated Viral Infections

1999 ◽  
Vol 5 (S2) ◽  
pp. 1098-1099
Author(s):  
Sara E. Miller
Keyword(s):  
Electron Microscopy ◽  
Human Immunodeficiency Virus ◽  
Viral Infections ◽  
Immune Defense ◽  
Detection Methods ◽  
Aids Patients ◽  
Viral Pathogens ◽  
Thin Sectioning ◽  
Immunodeficiency Virus ◽  
Life Threatening

Infection with human immunodeficiency virus (HIV) eventually causes a profound decrease in the body's ability to eradicate or control infections with microorganisms, including viruses. Some infections in AIDS patients are due to common organisms which are of little significance in immunocompetent individuals. Other organisms can be harbored continuously, occasionally causing disease, but normally being suppressed after a heightened immune defense; in AIDS patients, these infections can be life-threatening. Further, practices that predispose to HIV infection also permit entry of other organisms, such as hepatitis and herpesviruses. Electron microscopy is beneficial as an adjunct to other modalities for viral detection. Methods for identifying viruses, both in fluids by negative staining and in tissues by thin sectioning, have been published. Some viral pathogens, including HIV itself, are best documented by other means.HIV has been demonstrated by EM in infected individuals, but because it destroys and makes scarce the cells for which it has an affinity, it is difficult to find them.

scholarly journals Dengue Virus and the Relationship with MicroRNAs

2020 ◽  
Author(s):  
Samir Casseb ◽  
Karla de Melo
Keyword(s):  
Dengue Virus ◽  
Viral Infection ◽  
Viral Infections ◽  
Immune Defense ◽  
Tropical Regions ◽  
Denv Serotypes ◽  
History Of ◽  
Infection Processes ◽  
The Relationship

Dengue is an acute febrile disease caused by a virus of the genus Flavivirus, family Flaviviridae, endemic in tropical regions of the globe. The agent is a virus with single-stranded RNA, classified into four distinct dengue virus (DENV) serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The host’s innate and adaptive immune responses play an essential role in determining the natural history of viral infections, especially in dengue. In this context, it has observed in recent years that the presence of RNA interference (RNAi) in viral infection processes is increasing, as well as immune defense. The context microRNAs (miRNAs) go for stood out, as their presence during viral infection, both in the replication of the virus and in the defense against these infections, becomes increasingly noticeable, therefore, making it increasingly necessary to better understand the role of these small RNAs within viral infection by DENV and what their consequences are in aggravating the consequences of patients affected by this disease.

scholarly journals The Role of Peptide Signals Hidden in the Structure of Functional Proteins in Plant Immune Responses

2019 ◽  
Vol 20 (18) ◽  
pp. 4343 ◽  
Author(s):  
Irina Lyapina ◽  
Anna Filippova ◽  
Igor Fesenko
Keyword(s):  
Immune Responses ◽  
Defense Responses ◽  
Innate Immune ◽  
Functional Protein ◽  
Diverse Range ◽  
Peptide Signals ◽  
Plant Pathogen Interactions ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Plants have evolved a sophisticated innate immune system to cope with a diverse range of phytopathogens and insect herbivores. Plasma-membrane-localized pattern recognition receptors (PRRs), such as receptor-like kinases (RLK), recognize special signals, pathogen- or damage-associated molecular patterns (PAMPs or DAMPs), and trigger immune responses. A growing body of evidence shows that many peptides hidden in both plant and pathogen functional protein sequences belong to the group of such immune signals. However, the origin, evolution, and release mechanisms of peptide sequences from functional and nonfunctional protein precursors, known as cryptic peptides, are largely unknown. Various special proteases, such as metacaspase or subtilisin-like proteases, are involved in the release of such peptides upon activation during defense responses. In this review, we discuss the roles of cryptic peptide sequences hidden in the structure of functional proteins in plant defense and plant-pathogen interactions.

scholarly journals Pathogen-Associated Molecular Patterns Induced Crosstalk between Dendritic Cells, T Helper Cells, and Natural Killer Helper Cells Can Improve Dendritic Cell Vaccination

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Tammy Oth ◽  
Joris Vanderlocht ◽  
Catharina H. M. J. Van Elssen ◽  
Gerard M. J. Bos ◽  
Wilfred T. V. Germeraad
Keyword(s):  
Dendritic Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Specific Pattern ◽  
Dendritic Cell Vaccination ◽  
T Helper ◽  
Cell Responses ◽  
Helper Cells ◽  
Molecular Patterns

A coordinated cellular interplay is of crucial importance in both host defense against pathogens and malignantly transformed cells. The various interactions of Dendritic Cells (DC), Natural Killer (NK) cells, and T helper (Th) cells can be influenced by a variety of pathogen-associated molecular patterns (PAMPs) and will lead to enhanced CD8+effector T cell responses. Specific Pattern Recognition Receptor (PRR) triggering during maturation enables DC to enhance Th1 as well as NK helper cell responses. This effect is correlated with the amount of IL-12p70 released by DC. Activated NK cells are able to amplify the proinflammatory cytokine profile of DC via the release of IFN-γ. The knowledge on how PAMP recognition can modulate the DC is of importance for the design and definition of appropriate therapeutic cancer vaccines. In this review we will discuss the potential role of specific PAMP-matured DC in optimizing therapeutic DC-based vaccines, as some of these DC are efficiently activating Th1, NK cells, and cytotoxic T cells. Moreover, to optimize these vaccines, also the inhibitory effects of tumor-derived suppressive factors, for example, on the NK-DC crosstalk, should be taken into account. Finally, the suppressive role of the tumor microenvironment in vaccination efficacy and some proposals to overcome this by using combination therapies will be described.

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