scholarly journals Genetic Diversity of Toll-Like Receptors and Immunity toM. lepraeInfection

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Bryan E. Hart ◽  
Richard I. Tapping
Keyword(s):  
Association Studies ◽  
Genetic Association Studies ◽  
Adaptive Immune System ◽  
Mycobacterial Infection ◽  
Innate Immune ◽  
Genetic Associations ◽  
Toll Like Receptors ◽  
Adaptive Immune ◽  
Polymorphic Variants ◽  
And Function

Genetic association studies of leprosy cohorts across the world have identified numerous polymorphisms which alter susceptibility and outcome to infection withMycobacterium leprae. As expected, many of the polymorphisms reside within genes that encode components of the innate and adaptive immune system. Despite the preponderance of these studies, our understanding of the mechanisms that underlie these genetic associations remains sparse. Toll-like receptors (TLRs) have emerged as an essential family of innate immune pattern recognition receptors which play a pivotal role in host defense against microbes, including pathogenic strains of mycobacteria. This paper will highlight studies which have uncovered the association of specific TLR gene polymorphisms with leprosy or tuberculosis: two important diseases resulting from mycobacterial infection. This analysis will focus on the potential influence these polymorphic variants have on TLR expression and function and how altered TLR recognition or signaling may contribute to successful antimycobacterial immunity.

Immune mechanisms: innate immunity

2016 ◽  
Author(s):  
Troy Noordenbos ◽  
Dominique Baeten
Keyword(s):  
Immune System ◽  
Adaptive Immune System ◽  
Signs And Symptoms ◽  
Innate Immune ◽  
Molecular Characteristics ◽  
Target Tissue ◽  
Hla B27 ◽  
Genetic Associations ◽  
Immune Mechanisms ◽  
Adaptive Immune

Innate immune mechanisms are strongly implied in the pathophysiology of spondyloarthritis (SpA). This chapter discusses available data on the role of the innate immune system in relation to HLA-B27, genetic associations, and the cellular and molecular characteristics of disease target tissue. Regarding the linkage with MCH-class I molecule HLA-B27, the chapter discusses the arthritogenic peptide hypothesis and three popular antigen-independent theories. The genetic architecture of the disease argues against a role for the adaptive immune system and identifies cytokine pathways, such as IL-1, TNF, and IL-23/IL-17. In experimental as well as in human SpA, the importance of these cytokine pathways are confirmed by effective reduction of signs and symptoms upon blockade of specific molecules. In-depth cellular and molecular analysis of the target tissue identifies a contribution of cells with strong innate features, rather than cells of the adaptive immune system.

Dendritic cells in multiple sclerosis: key players in the immunopathogenesis, key players for new cellular immunotherapies?

2013 ◽  
Vol 19 (8) ◽  
pp. 995-1002 ◽  
Author(s):  
AH Nuyts ◽  
WP Lee ◽  
R Bashir-Dar ◽  
ZN Berneman ◽  
N Cools
Keyword(s):  
Multiple Sclerosis ◽  
Dendritic Cells ◽  
Adaptive Immune System ◽  
Innate Immune ◽  
Adaptive Immune ◽  
Dc Function ◽  
Key Players ◽  
Plasmacytoid Dcs ◽  
And Function

Many studies have demonstrated the role of the adaptive immune system in the pathogenesis of multiple sclerosis (MS). Recent data suggest that dendritic cells (DCs), which are innate immune cells, also contribute to the pathogenesis of MS. In patients with MS, DCs are abundantly present in brain lesions, and display an altered phenotype and/or function as compared with this in healthy controls. DCs are thus in the position to pathologically influence the effector function of (auto-reactive) T and B cells. Interestingly, current first-line immunomodulating therapies for MS have been shown to restore DC phenotype and function, albeit in a non-specific manner. To date, clinical trials using agents specifically targeting DC function are ongoing. Moreover, several studies worldwide are currently investigating possible strategies to develop tolerogenic DCs. This review focuses on the phenotypic and functional alterations of conventional DCs and plasmacytoid DCs in patients with MS. Furthermore, we discuss how existing immunomodulating therapies for MS patients affect DC function and address future perspectives in the development of immunotherapies specifically targeting DCs.

A common pathway mediated through Toll-like receptors leads to T- and natural killer–cell immunosuppression

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1437-1447 ◽  
Author(s):  
Ilan Vaknin ◽  
Liora Blinder ◽  
Lynn Wang ◽  
Roi Gazit ◽  
Elena Shapira ◽  
...  
Keyword(s):  
Natural Killer ◽  
Chronic Inflammation ◽  
Nk Cell ◽  
Killer Cell ◽  
Adaptive Immune System ◽  
Suppressor Cells ◽  
Toll Like Receptors ◽  
Down Regulation ◽  
Myeloid Suppressor Cells ◽  
Adaptive Immune

Abstract T- and natural killer (NK)–cell immunosuppression associated with ζ-chain down-regulation has been described in cancer, autoimmune, and infectious diseases. However, the precise stimuli leading to this bystander phenomenon in such different pathogen-dependent and sterile pathologies remained unresolved. Here, we demonstrate that Toll-like receptors (TLRs) play a major role in the induction of innate and adaptive immune system suppression; repetitive administration of single TLR 2, 3, 4, or 9 agonists, which do not exhibit any virulent or immune invasive properties, was sufficient to induce a bystander NK- and T-cell immunosuppression associated with ζ-chain down-regulation mediated by myeloid suppressor cells, as observed in the course of active pathologies. We identified a 35-amino acid (aa) region within the ζ-chain as being responsible for its degradation under TLR-mediated chronic inflammation. Furthermore, we provide evidence that ζ-chain levels could serve as a biomarker for chronic inflammation-dependent immunosuppression. Thus, although acute TLR-mediated activation could be beneficial in clearing pathogens or may serve as an immune adjuvant, such activation could be detrimental under sustained conditions.

scholarly journals Adipocytes, Innate Immunity and Obesity: A Mini-Review

2021 ◽  
Vol 12 ◽  
Author(s):  
Alecia M. Blaszczak ◽  
Anahita Jalilvand ◽  
Willa A. Hsueh
Keyword(s):  
Adipose Tissue ◽  
Immune System ◽  
Immune Cells ◽  
Adaptive Immune System ◽  
Innate Immune ◽  
Lymphoid Cells ◽  
Innate Immune Cells ◽  
Adaptive Immune

The role of adipose tissue (AT) inflammation in obesity and its multiple related-complications is a rapidly expanding area of scientific interest. Within the last 30 years, the role of the adipocyte as an endocrine and immunologic cell has been progressively established. Like the macrophage, the adipocyte is capable of linking the innate and adaptive immune system through the secretion of adipokines and cytokines; exosome release of lipids, hormones, and microRNAs; and contact interaction with other immune cells. Key innate immune cells in AT include adipocytes, macrophages, neutrophils, and innate lymphoid cells type 2 (ILC2s). The role of the innate immune system in promoting adipose tissue inflammation in obesity will be highlighted in this review. T cells and B cells also play important roles in contributing to AT inflammation and are discussed in this series in the chapter on adaptive immunity.

scholarly journals Vertebrate cardiac regeneration: evolutionary and developmental perspectives

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephen Cutie ◽  
Guo N. Huang
Keyword(s):  
Cardiac Injury ◽  
Adaptive Immune System ◽  
Cardiac Regeneration ◽  
Heart Regeneration ◽  
Adaptive Immune ◽  
Selective Pressures ◽  
Trade Offs ◽  
Lower Vertebrates ◽  
Complex Adaptive ◽  
And Function

AbstractCardiac regeneration is an ancestral trait in vertebrates that is lost both as more recent vertebrate lineages evolved to adapt to new environments and selective pressures, and as members of certain species developmentally progress towards their adult forms. While higher vertebrates like humans and rodents resolve cardiac injury with permanent fibrosis and loss of cardiac output as adults, neonates of these same species can fully regenerate heart structure and function after injury – as can adult lower vertebrates like many teleost fish and urodele amphibians. Recent research has elucidated several broad factors hypothesized to contribute to this loss of cardiac regenerative potential both evolutionarily and developmentally: an oxygen-rich environment, vertebrate thermogenesis, a complex adaptive immune system, and cancer risk trade-offs. In this review, we discuss the evidence for these hypotheses as well as the cellular participators and molecular regulators by which they act to govern heart regeneration in vertebrates.

scholarly journals The neuropeptide receptor NMUR-1 regulates the specificity of C. elegans innate immunity against pathogen infection

2021 ◽  
Author(s):  
Phillip Wibisono ◽  
Shawndra Wibisono ◽  
Jan Watteyne ◽  
Chia-Hui Chen ◽  
Durai Sellegounder ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune System ◽  
Immune Responses ◽  
Adaptive Immune System ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Immune Genes ◽  
C Elegans ◽  
Adaptive Immune ◽  
Functional Assays

A key question in current immunology is how the innate immune system generates high levels of specificity. Like most invertebrates, Caenorhabditis elegans does not have an adaptive immune system and relies solely on innate immunity to defend itself against pathogen attacks, yet it can still differentiate different pathogens and launch distinct innate immune responses. Here, we have found that functional loss of NMUR-1, a neuronal GPCR homologous to mammalian receptors for the neuropeptide neuromedin U, has diverse effects on C. elegans survival against various bacterial pathogens. Transcriptomic analyses and functional assays revealed that NMUR-1 modulates C. elegans transcription activity by regulating the expression of transcription factors, which, in turn, controls the expression of distinct immune genes in response to different pathogens. Our study has uncovered a molecular basis for the specificity of C. elegans innate immunity that could provide mechanistic insights into understanding the specificity of vertebrate innate immunity.

scholarly journals Optimizing Dendritic Cell-Based Immunotherapy: Tackling the Complexity of Different Arms of the Immune System

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Ilse Van Brussel ◽  
Zwi N. Berneman ◽  
Nathalie Cools
Keyword(s):  
Immune System ◽  
Dendritic Cell ◽  
Immune Responses ◽  
Adaptive Immune System ◽  
Cellular Mechanisms ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
New Ideas ◽  
And Function

Earlier investigations have revealed a surprising complexity and variety in the range of interaction between cells of the innate and adaptive immune system. Our understanding of the specialized roles of dendritic cell (DC) subsets in innate and adaptive immune responses has been significantly advanced over the years. Because of their immunoregulatory capacities and because very small numbers of activated DC are highly efficient at generating immune responses against antigens, DCs have been vigorously used in clinical trials in order to elicit or amplify immune responses against cancer and chronic infectious diseases. A better insight in DC immunobiology and function has stimulated many new ideas regarding the potential ways forward to improve DC therapy in a more fundamental way. Here, we discuss the continuous search for optimal in vitro conditions in order to generate clinical-grade DC with a potent immunogenic potential. For this, we explore the molecular and cellular mechanisms underlying adequate immune responses and focus on most favourable DC culture regimens and activation stimuli in humans. We envisage that by combining each of the features outlined in the current paper into a unified strategy, DC-based vaccines may advance to a higher level of effectiveness.

Changes in immune responses to oxidized LDL epitopes during aging in hypercholesterolemic apoE(−/−) mice

2006 ◽  
Vol 291 (6) ◽  
pp. R1644-R1650 ◽  
Author(s):  
Paul C. Dimayuga ◽  
Xiaoning Zhao ◽  
Juliana Yano ◽  
Kuang-Yuh Chyu
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Time Course ◽  
Oxidized Ldl ◽  
Adaptive Immune Response ◽  
Adaptive Immune System ◽  
Innate Immune ◽  
Collagen Content ◽  
Aortic Sinus ◽  
Adaptive Immune

Atherosclerosis is a disease associated with aging and is subject to modulation by both the innate and adaptive immune system. The time course of age-dependent changes in immune regulation in the context of atherosclerosis has not been characterized. This study aims to describe alteration of the immune responses to oxidized LDL (oxLDL) during aging that is associated with changes in plaque size and phenotype in apoE(−/−) mice. Mice fed a Western diet were euthanized at 15–17, 36, or >52 wk of age. The descending aortas were stained for assessment of extent of atherosclerosis. Plaque lipid, macrophage, and collagen content were evaluated in aortic sinus lesions. The adaptive immune response to oxLDL was assessed using anti-malondialdehyde-oxidized LDL (MDA-LDL) and copper-oxidized LDL (Cu-oxLDL) IgG, and the innate immune response was assessed using anti-Cu-oxLDL and phosphorylcholine (PC) IgM. Aging was associated with a significant increase in plaque area and collagen content and a decrease in plaque macrophage and lipid content. MDA-LDL IgG significantly increased at 36 wk but was reduced in mice >52 wk. Cu-oxLDL IgG increased with age and IgG-apoB immune complexes were increased in the >52 wk group. Cu-oxLDL and PC IgM significantly increased with age. The expression of splenic cytokines such as IFN-γ, IL-4, and IL-10 increased with age. Our study shows a generalized increase in innate immune responses associated with progression of atherosclerosis and a less inflammatory and less lipid-containing plaque phenotype during aging. The adaptive immune response appeared to be less generalized, with a specific reduction in MDA-LDL IgG.

scholarly journals Enteroendocrine cells express functional Toll-like receptors

2007 ◽  
Vol 292 (6) ◽  
pp. G1770-G1783 ◽  
Author(s):  
Milena Bogunovic ◽  
Shaival H. Davé ◽  
Jeremy S. Tilstra ◽  
Diane T. W. Chang ◽  
Noam Harpaz ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Innate Immune ◽  
Calcium Flux ◽  
Intestinal Epithelial ◽  
Toll Like Receptors ◽  
Inhibitory Protein ◽  
Inflammatory Gene ◽  
Similar Expression Pattern ◽  
And Function

Intestinal epithelial cells (IECs) provide a physical and immunological barrier against enteric microbial flora. Toll-like receptors (TLRs), through interactions with conserved microbial patterns, activate inflammatory gene expression in cells of the innate immune system. Previous studies of the expression and function of TLRs in IECs have reported varying results. Therefore, TLR expression was characterized in human and murine intestinal sections, and TLR function was tested in an IEC line. TLR1, TLR2, and TLR4 are coexpressed on a subpopulation of human and murine IECs that reside predominantly in the intestinal crypt and belong to the enteroendocrine lineage. An enteroendocrine cell (EEC) line demonstrated a similar expression pattern of TLRs as primary cells. The murine EEC line STC-1 was activated with specific TLR ligands: LPS or synthetic bacterial lipoprotein. In STC-1 cells stimulated with bacterial ligands, NF-κB and MAPK activation was demonstrated. Furthermore, the expression of TNF and macrophage inhibitory protein-2 were induced. Additionally, bacterial ligands induced the expression of the anti-inflammatory gene transforming growth factor-β. LPS triggered a calcium flux in STC-1 cells, resulting in a rapid increase in CCK secretion. Finally, conditioned media from STC-1 cells inhibited the production of nitric oxide and IL-12 p40 by activated macrophages. In conclusion, human and murine IECs that express TLRs belong to the enteroendocrine lineage. Using a murine EEC model, a broad range of functional effects of TLR activation was demonstrated. This study suggests a potential role for EECs in innate immune responses.

Antibody equivalent molecules of the innate immune system: parallels between innate and adaptive immune proteins

2010 ◽  
Vol 16 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Nades Palaniyar
Keyword(s):  
Pattern Recognition ◽  
Immune System ◽  
Innate Immune System ◽  
Adaptive Immune System ◽  
Surfactant Protein ◽  
Innate Immune ◽  
Future Research ◽  
Surfactant Protein D ◽  
Adaptive Immune ◽  
Carbohydrate Arrays

Soluble pattern-recognition innate immune proteins functionally resemble the antibodies of the adaptive immune system. Two major families of such proteins are ficolins and collectins or collagenous lectins (e.g. mannose-binding lectin [MBL], surfactant proteins [SP-A and SP-D] and conglutinin). In general, subunits of ficolins and collectins recognize the carbohydrate arrays of their targets via globular trimeric carbohydrate-recognition domains (CRDs) whereas IgG, IgM and other antibody isotypes recognize proteins via dimeric antigen-binding domains (Fab). Considering the structure and functions of these proteins, ficolins and MBL are analogous to molecules with the complement activating functions of C1q and the target recognition ability of IgG. Although the structure of SP-A is similar to MBL, it does not activate the complement system. Surfactant protein-D and conglutinin could be considered as the collagenous non-complement activating giant IgMs of the innate immune system. Proteins such as peptidoglycan-recognition proteins, pentraxins and agglutinin gp-340/DMBT1 are also pattern-recognition proteins. These proteins may be considered as different isotypes of antibody-like molecules. Proteins such as defensins, cathelicidins and lactoferrins directly or indirectly alter microbes or microbial growth. These proteins may not be considered as antibodies of the innate immune system. Hence, ficolins and collectins could be considered as specialized ‘antibodies of the innate immune system’ instead of ‘ante-antibody’ innate immune molecules. The discovery, structure, functions and future research directions of many of these soluble proteins and receptors such as Toll-like and NOD-like receptors are discussed in this special issue of Innate Immunity.

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