Innate Immune System

Decent Essays
Innate immunity constitutes the first line of defense and is fundamental for the recognition and the initiation of an inflammatory response against microorganism. Maintenance of homeostasis is a primary function of the innate immune system and it is achieved through immune surveillance by pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) and nucleotide-binding domain leucine-rich repeat containing receptors (NLRs). The PRR’s are predominantly expressed by cells of the myeloid lineage. TLRs and NLRs are distributed throughout the gastrointestinal mucosa mostly being expressed in the epithelium and in lamina propria cells. The gastrointestinal mucosa surfaces are in constant interaction with a wide variety of commensal …show more content…
There are several things that can arm the innate immune system. Microbial pathogens and stress factors pose a threat to the host and both can initiate the inflammatory cascade. The innate system has several mechanisms to counter the invasion by theses harmful agents. This include anatomical barrios such as skin and mucus membranes that prevent spreading throughout the body, oposination and removal of the invading factor by PRR’s. PRR’s are expressed in macrophages, dendrite cells and epithelial cells and are the frontline of defense against infections. PRRs activate intracellular signals that collaborate for activation of host defense. Currently, four different classes of PRRs have been identified, including TLR, RIG-I-like RNA helicases (RLH), C-type lectin receptors (CLR) and NLR. These germline-encoded PRRs are capable of recognizing highly conserved, pathogen-associated molecular patterns (PAMPs), such as lippopolysaccharide (LPS), release of danger signals, such as Adenosine-5 '-triphosphate (ATP), or danger-associated molecular patterns (DAMPs) induced by either pathogens or sterile inflammatory insults. PRRs can be subdivided into two major classes based on their subcellular localization. TLR’s and CLR are embedded in the cellular membrane and survey the extracellular milieu & endosomal compartments for PAMP’s. DNA sensors, NLR’s and RLR’s are cytoplasm immersed particles and survey the …show more content…
The first signal is implemented by microbial molecules and cytokines that that bind to TLR receptor and induces the up-regulation the transcription of nuclear factor κB, which will synthesis NLRP3, pro-IL-1β and pro-IL-18. Common priming signals for immune cells of the body and human RPE cells are LPS, tumor necrosis factor-α (TNF-α), nitric oxide, and IL-1α. Once the NLRP3 is activated, it recruits ASC and mediates the proximity-induced procaspase-1 autoactivation. The assembled NLRP3 inflammasome then turns itself into a cytokine processing platform by cleaving pro-IL-1β and pro-IL-18 into mature cytokines and releasing them into extracellular space for downstream

Related Documents

  • Decent Essays

    Adaptive Immune Response

    • 785 Words
    • 4 Pages

    B cells express specific antigen receptors (immunoglobulin molecules) on their cell surface during their development and, when mature in the bone marrow, secrete soluble immunoglobulins (antibodies) into the extracellular fluids. Each B cell is genetically programmed to express a surface receptor…

    • 785 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    It depends on formation large number of antigen receptors. The antigen presenting cells include the macrophages, dendritic cells and ECs. They allow the antigens to activate T-cells. The activated T cells then secrete great amount of cytokines that modulate atherogenesis. The T helper cells are divided into two types.…

    • 962 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    Microbiota Research Paper

    • 1153 Words
    • 5 Pages

    Dendritic cells contain pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs) that recognize microbial associated molecular patterns (MAMPs). Both pathogen and commensal microbiota contain MAMPs such as peptidoglycans, lipopolysaccharides and flagella. Activation of TLRs sets off a signalling cascade of nuclear factor-kappa B (NF-kB) to initiates the production of cytokines that results in an inflammatory response (20). Dendritic cell also sample bacterium and transfers it to the mesenteric lymph nodes through the lymphatics of the intestine. Once the activated dendritic cell reaches the Peyer’s patches they interact with B-cells to produce Immunoglobulin A (IgA).…

    • 1153 Words
    • 5 Pages
    Decent Essays
  • Decent Essays

    Smad proteins in the resting state realize passive nucleo cytoplasmic shuttling, that is controlled by two opposing signals: the nuclear localization signal (NLS) in the MH1 domain and the nuclear export signal (NES) in the MH2 domain. Then they interact with DNA binding proteins or directly regulate transcriptional activity, either as monomers or in association with Smad4 (Carreira et al., 2014 [6]; Liu et al., 1996 [49]). In the nucleus they can regulate transcription of target genes by directly binding via their MH1 domain to specific DNA sequences depends on the formation of Smad complex with other DNA-binding proteins. The R-Smad/C-Smad heterodimer complex interacts with various transcription factors, co-activators and co-repressors to modulate gene expression (ten Dijke et al., 2000 [46]; Kusanagi et al., 2000 [50]). Smad complex binds the promotor regions of several BMP-responsive genes.…

    • 931 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    T And B Lymphocytes

    • 1698 Words
    • 7 Pages

    The proliferation of TL is induced by large amounts of IL-2 that are produced by Th1 lymphocytes. The cytokine, INF-γ is also produced by Th1 lymphocytes and serves to activate infected macrophages. The response made by Th1 lymphocytes is crucial in combating intracellular pathogens. Without a Th1 response, autoimmune rheumatic diseases and multiple sclerosis (MS) are prevalent. The T2 lymphocytes promote the production of antibodies through the production of IL-4, IL-5, IL-6 and IL-10.…

    • 1698 Words
    • 7 Pages
    Decent Essays
  • Decent Essays

    T Cells Essay

    • 1316 Words
    • 6 Pages

    The T cells are a type of white cells, which are important to the immune system, and contain a system that adjusts the body’s reaction to specific pathogens, this being the center of its adaptive immunity. T cells are like soldiers who search out and destroy the targeted invaders. T cells can be compared to soilders, they search out and demolish intruders. There has been a literature attention on the function of the administration in cancer immunity in T-Cells. The T cells are now known to take place an essential task in the evolution of cancer and conceals a tumor - specific immunity.…

    • 1316 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    These steps include dendritic cells promoting tumor antigens obtained from tumor microenvironments or dead tumor cells, recruitment of activated T-cells to cause responses and circumventing immunosuppression in the tumor microenvironment (Kershaw, Devaud et. 2013). Dendritic cells can present antigens using MHC class I and II molecules by moving to the lymph nodes to expose antigens to T cells upon receiving a stimulus (Vegh , Wang et. 1993). The activated naïve T cells can migrate to region containing antigens and target cancer cells displaying these antigens.…

    • 1172 Words
    • 5 Pages
    Decent Essays
  • Decent Essays

    Pathogenic Bacteria

    • 1075 Words
    • 4 Pages

    The occurrence of such diseases requires unique strategies, which assist bacteria to survive inside the host and evade their immune response (Akira et al., 2006). Several pathogenic bacteria have developed efficient capabilities to counteract…

    • 1075 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    Bacterial Biofilms

    • 1030 Words
    • 4 Pages

    In this process, pathogens that have been seized by antibodies stick out like red flags; this alerts macrophages, neutrophils and other phagocytic cells to entomb and kill the bacteria. Complement activation directly clears infected cells, and destroys or lyses the foreign microbes. T cells, which include CD8+ and CD4+ cells kill infected cells and activate other immune cells. Cytokines are small proteins secreted by immune cells. They are key in immune cell growth, activation, and…

    • 1030 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    CD4 + T Cells

    • 1168 Words
    • 5 Pages

    Regulatory T cells are part of the adaptive immune response and are derived from the thymus. Treg cells are known as CD4+CD25+ T cells. They maintain immune cell homeostasis during inflammation and disease. NKT cells are part of the innate immune response, and are the first line of defense against tumors and viruses; they recognize infected cells by their down regulation of the major histocompatibility complex (MHC) class 1 molecules. NKT cells release cytokines and recruit other immune cells.…

    • 1168 Words
    • 5 Pages
    Decent Essays

Related Topics