Innate immunity
Dotaz
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svazky : ilustrace ; 28 cm
- MeSH
- endotoxiny MeSH
- přirozená imunita * MeSH
- Publikační typ
- periodika MeSH
- Konspekt
- Lékařské vědy. Lékařství
- NLK Obory
- alergologie a imunologie
- bakteriologie
Buněčné i humorální složky přirozené imunity jsou schopny identifikovat „signály nebezpečí“ exogenního i endogenního původu. Exogenní signály nebezpečí jsou představovány evolučně konzervovanými mozaikami nebezpečných vzorů, které jsou společné pro patogenní mikroorganizmy. Endogenní signály nebezpečí vznikají při poškození buněk a tkání, oxidativním stresu nebo chemickou modifikací vlastních struktur. Nebezpečné signály jsou identifikovány několika rodinami membránových molekul vyjádřených na povrchu buněk přirozené imunity. Patří mezi ně rodina receptorů TLR, která je funkčně spojena s nitrobuněčnou signální cestou NF-κB. Prostřednictvím transkripčního faktoru NF-κB je stimulován rozvoj zánětové reakce.
Cellular and humoral components of innate immunity are able to identify danger signals both of the exogenous and endogenous origin. Exogenous danger signals are evolutionary conserved mosaics of danger patterns which are frequent in pathogenic microbes. Endogenous danger signals are raised during damage of self structures, by oxidative stress and/or by chemical modification of self molecules. Danger signals are identified by several families of molecules which are expressed on the surfaces of innate immunity cells. Among them the TLR receptors family which is associated with intracellular signaling pathway NF-κB is one of the most important. The inflammatory response is induced via activated NF-κB transcription factor.
sv.
- MeSH
- přirozená imunita * MeSH
- Publikační typ
- periodika MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- alergologie a imunologie
Infectious disease
[1st ed.] xi, 410 s. : il.
The innate immunity is frequently accepted as a first line of relatively primitive defense interfering with the pathogen invasion until the mechanisms of 'privileged' adaptive immunity with the production of antibodies and activation of cytotoxic lymphocytes 'steal the show'. Recent advancements on the molecular and cellular levels have shaken the traditional view of adaptive and innate immunity. The innate immune memory or 'trained immunity' based on metabolic changes and epigenetic reprogramming is a complementary process insuring adaptation of host defense to previous infections.Innate immune cells are able to recognize large number of pathogen- or danger- associated molecular patterns (PAMPs and DAMPs) to behave in a highly specific manner and regulate adaptive immune responses. Innate lymphoid cells (ILC1, ILC2, ILC3) and NK cells express transcription factors and cytokines related to subsets of T helper cells (Th1, Th2, Th17). On the other hand, T and B lymphocytes exhibit functional properties traditionally attributed to innate immunity such as phagocytosis or production of tissue remodeling growth factors. They are also able to benefit from the information provided by pattern recognition receptors (PRRs), e.g. γδT lymphocytes use T-cell receptor (TCR) in a manner close to PRR recognition. Innate B cells represent another example of limited combinational diversity usage participating in various innate responses. In the view of current knowledge, the traditional black and white classification of immune mechanisms as either innate or an adaptive needs to be adjusted and many shades of gray need to be included.
- MeSH
- adaptivní imunita * MeSH
- B-lymfocyty imunologie MeSH
- buňky NK imunologie MeSH
- cytokiny genetika imunologie MeSH
- lidé MeSH
- přirozená imunita * MeSH
- T-lymfocyty imunologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- MeSH
- Drosophila melanogaster genetika imunologie MeSH
- genetické jevy fyziologie imunologie MeSH
- imunitní systém fyziologie MeSH
- lidé MeSH
- přirozená imunita fyziologie MeSH
- probiotika metabolismus terapeutické užití MeSH
- T-lymfocyty fyziologie imunologie MeSH
- toll-like receptory fyziologie genetika imunologie MeSH
- zánět genetika imunologie MeSH
- Check Tag
- lidé MeSH
Začiatočné rozpoznanie mikróbov, ktoré vniknú do organizmu, sa zakladá na ich geneticky zakódovaných molekulových vzoroch patogénnosti (PAMPs), ktoré umožňujú odpovedať na mikróbnu inváziu ihneď, čiže ešte pred vznikom aktívnej špecifickej imunity. Táto odpoveď hostiteľa na infekciu a poranenie sa realizuje prostredníctvom neustále sa rozširujúcej skupiny receptorov patriacich do veľkorodiny receptorov pre interleukín-1 (IL-1Rs) a receptorov podobných Toll (TLRs). Členovia obidvoch týchto rodín obsahujú v cytoplamových častiach ich molekúl doménu TIR (Toll/IL-1R). Doteraz sa zistilo desať IL-1Rs (vrátane IL-1RI a IL-18R) a desať TLRs (TLR1 až TLR10). Exprimujú sa najmä na bunkách, ktoré sa nachádzajú na tkanivách prichádzajúcich do kontaktu s vonkajším prostredím. Aktivácia TLRs má za následok aktiváciu priamych antimikróbnych mechanizmov, ako súčasti prirodzenej imunity, expresiu kostimulačných molekúl a uvoľnenie cytokínov, ktoré regulujú adaptívnu imunitnú odpoveď. Prenos signálov cez tieto receptory môže zodpovedať aj za stimuláciu dozrievania imunitného systému a môže sa preto zúčastňovať na patogenéze alergických chorôb. Využitie poznatkov o TLRs sa pravdepodobne v budúcnosti bude dať preto využiť pri nových účinných postupoch liečby osobitne atopických chorôb. Genetické a vývojové variácie v expresii TLRs môžu ovplyvňovať individuálnu predispozíciu na infekcie v detskom veku a prispievať k zvýšenej citlivosti nielen na alergie, ale aj na zápalové a autoimunitné choroby.
Initial recognition of microbes, as they enter the body, is based on germ line-encoded pathogen-associated molecular patterns (PAMPs) to respond immediately to the microbial invasion before the development of active specific immunity. This host response to infection and injury is performed through an expanding group of receptors belonging to the superfamily of interleukin-1 receptors (IL-1Rs) and Toll-like receptors (TLRs). They both contain the Toll-IL-1 receptor (TIR) domain which occurs in the cytosolic region. So far, ten IL-1Rs (including IL-1RI and IL-18R) and ten TLRs (TLR1 to TLR10) have been revealed. They are predominatly expressed on cells at the interface of the body with the environment. The activation of TLRs leads to direct antimicrobial pathways, as a part of innate immunity, to the expression of co-stimulatory molecules and to the release of cytokines that instruct the adaptive immune response. Signalling via these receptors may be also responsible for driving the maturation of the adult immune system and therefore it may participate in the pathogenesis of allergic diseases. Exploitation of the TLR signalling will probably lead to novel effective therapies for these diseases. Genetic and developmental variations in the expression of TLRs may affect the individual predisposition to infections in childhood and may contribute to the increased susceptibility not only to allergies but to inflammatory and autoimmune diseases as well.
Celulárnu adaptívnu imunitnú odpověď zabezpečujú T-lymfocyty. Tieto sú vo svojej funkcii róznorodé, čo nemóže zabezpečit'jedna skupina buniek, ale len viaceré. Vskutku, na základe odlišných biologických vlastností sa T-lymfocyty delia na tri základné subpopulácie - pomocné, cytotoxické a regulačně. Navýše pomocné T-lymfocyty možno rozdělit' na ďalšie subpopulácie, ktorých v súčasnosti poznáme už 6: THl, TH2, TH5,TH9,TH17 a TH22. TH2-lymfocyty sú principiálnymi buňkami, ktoré zabezpečujú obranyschopnost' proti helmintom. Vznikajú však pomerne neskoro, takže sa hľadali iné bunky, ktoré by produkciou rovnakých cytokínov ako syntetizujú TH 2-lymfocyty túto odpoveď iniciovali okamžite po infestácii parazitmi. Ich objavu predchádzalo objavenie IL-25 a IL-33, ktoré sú podstatnými cytokínmi indukujúcimi vznik týchto buniek, ktoré dostali pomenovanie „prirodzené imunitné bunky“. Zahrň ujú 4 rozdielne, ale príbuzné populácie buniek s názvami: nuocyty, bunky NH, MPP type2 a Ih2. Okrem fyziologickej úlohy boja proti helmintom, podpory vzniku TH2 adaptívnej imunity, možného blokovania zápalu v tukovom tkanive a diferenciácie na bazofily a mastocyty sa zúčastň ujú aj na imunopatologických procesoch – rozvoji alergie a zápalových chorôb čreva. K uvedeným prirodzeným bunkám možno ešte priradiť MAIT- a ILC22-bunky. Zabezpečujú antiinfekčnú ochranu a homeostázu tkanív.
Cellular adaptive immune response is mediated by T cells. Their biological activities are very heterogeneous what precludes to be mediated by a single cell population, rather by several ones. Really, T cells can be divided into three basic subpopulations – helper, cyto toxic and regulato- ry. Moreover, within T helper cell population six distinctive subsets can be distinguished - T H 1, T H 2, T H 5, T H 9, T H 17, and T H 22, respectively. T H 2 lymphocytes are principal cells responsible for fighting helminths. They appear, however, relatively late during the immune r esponse what made researchers to look for other cells endowed of T H 2 cytokines synthesis immediately after parasites infestation. Their discovery was successful because of previous description of new cytokines – IL-25 and IL-33, respectively, which are necessary for the induct ion of these novel innate immune cell populations (IICs). They comprise 4 different populations: nuocytes, NH2, MPP type2 and Ih2 cells, respectively. Their principal physiological role is not only to fight helminths, however, they support the induction of T H 2 adaptive immune response, down-regulate inflammation in a fat tissue and some of them differentiate into mast cells and basophils. ICCs can take part in immunopatholog ical processes too, esp. in allergy and IBD development. One can include to the innate cell population also other innate cells, namely MAIT an d ILC22, re- spectively. They are involved in anti-infectious immunity and tissue homeostasis.
Ticks are blood feeding parasites transmitting a wide variety of pathogens to their vertebrate hosts. The vector competence of ticks is tightly linked with their immune system. Despite its importance, our knowledge of tick innate immunity is still inadequate and the limited number of sufficiently characterized immune molecules and cellular reactions are dispersed across numerous tick species. The phagocytosis of microbes by tick hemocytes seems to be coupled with a primitive complement-like system, which possibly involves self/nonself recognition by fibrinogen-related lectins and the action of thioester-containing proteins. Ticks do not seem to possess a pro-phenoloxidase system leading to melanization and also coagulation of tick hemolymph has not been experimentally proven. They are capable of defending themselves against microbial infection with a variety of antimicrobial peptides comprising lysozymes, defensins and molecules not found in other invertebrates. Virtually nothing is known about the signaling cascades involved in the regulation of tick antimicrobial immune responses. Midgut immunity is apparently the decisive factor of tick vector competence. The gut content is a hostile environment for ingested microbes, which is mainly due to the antimicrobial activity of hemoglobin fragments generated by the digestion of the host blood as well as other antimicrobial peptides. Reactive oxygen species possibly also play an important role in the tick-pathogen interaction. The recent release of the Ixodes scapularis genome and the feasibility of RNA interference in ticks promise imminent and substantial progress in tick innate immunity research.
To give an overview about the role of the innate immunity in pathogenesis of intraamniotic inflammation in pregnancies complicated by preterm premature rupture of membranes. DESIGN: Review article. SETTING: Department of Clinical Immunology and Allergy, Faculty of Medicine and University Hospital in Hradec Kralove, Charles University in Prague. METHOD: An overview of recent published data. CONCLUSION: Immune system has an indisplaceable function throughout the successful pregnancy. Spontaneous labor is the result of many factors in which innate immunity playes a major role. The increased concentrations of proinflammatory markers (interleukin (IL)-1beta, IL-6, tumour necrosis factor alfa a IL-8) were found in amniotic fluid both in term and in preterm spontaneous delivery. These markers could be used for an early diagnosis of intraamnial infection/inflammation, which is the most common cause of preterm delivery (PTD) and preterm premature rupture of membranes (PPROM). The elevation of these markers could also better determine the patients with enhanced probability of PTD and PPROM.
- Klíčová slova
- amniochorion, intraamniální zánět, prozánětové markery,
- MeSH
- chorioamnionitida imunologie MeSH
- lidé MeSH
- předčasná porodní činnost imunologie MeSH
- předčasný odtok plodové vody imunologie MeSH
- přirozená imunita MeSH
- těhotenství MeSH
- Check Tag
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
