Toll-like receptor

(noun)

Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system as well as the digestive system. They are single, membrane-spanning, non-catalytic receptors that recognize structurally conserved molecules derived from microbes.

Related Terms

Examples of Toll-like receptor in the following topics:

  • Toll-Like Receptors

    • Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system as well as the digestive system.
    • Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system as well as the digestive system .
    • TLRs together with the Interleukin-1 receptors form a receptor superfamily, known as the "Interleukin-1 Receptor/Toll-Like Receptor Superfamily"; all members of this family have in common a so-called TIR (Toll-IL-1 receptor) domain.
    • Signaling pathway of Toll-like receptors.
    • The curved leucine-rich repeat region of Toll-like receptors, represented here by TLR3

  • Cell-Mediated Autoimmune Reactions

    • In coeliac disease it seems likely that B cells that recognize transglutamine tissue are helped by T cells that recognize gliadin.
    • A receptor, Peanut agglutinin receptor(PNAR)).
    • These ligands include B cell receptor (for antigen), IgG Fc receptors, CD21 (which binds complement C3d), Toll-like receptors 9 and 7 (which can bind DNA and nucleoproteins) and PNAR.
    • HLA-DQ (DQ) is a cell surface receptor type protein found on antigen presenting cells.
    • HLA-DQ (DQ) is a cell surface receptor type protein found on antigen presenting cells (APC).

  • T Cell Receptors

    • The T Cell Receptor (TCR) found on the surface of T cells is responsible for recognizing antigens.
    • The receptor that recognizes these peptide-MHC complexes is called the T Cell Receptor (TCR).
    • T cells also express other membrane receptors that do not recognize antigens but participate in responses to antigens; these are collectively called 'accessory molecules'.
    • T cell receptor consists of alpha and beta chains, a transmembrane domain, and a cytoplasmic region.
    • The presence of vacuoles, i.e. microscopic "holes" in the gray matter, gives the brain of BSE-affected cows a sponge-like appearance when tissue sections are examined in the lab.

  • Tissue Tropism in Animal Viruses

    • For example, viruses must bind to specific cell surface receptors to enter a cell.
    • If a cell does not express these receptors then the virus cannot normally infect it.
    • These cells express a CD4 receptor, to which the HIV virus can bind, through the gp120 and gp41 proteins on its surface .
    • Factors influencing viral tissue tropism include: 1) the presence of cellular receptors permitting viral entry, 2) availability of transcription factors involved in viral replication, 3) the molecular nature of the viral tropogen, and 4) the cellular receptors are the proteins found on a cell or viral surface.
    • These receptors are like keys allowing the viral cell to fuse with a cell or attach itself to a cell.

  • Tests That Differentiate Between T Cells and B cells

    • Methods used to differentiate T cells and B cells include staining cell surface receptors and functional assays like the T lymphocyte cytotoxicity assay.
    • They are divided into two types based on the pathogen recognition receptors they express on their surface.
    • T-lymphocytes can be distinguished from other lymphocytes like B cells and natural killer cells (NK cells) by the presence of a T cell receptor (TCR) on the cell surface.
    • Alternatively, B-cells can be distinguished from other lymphocytes like T cells and natural killer cells (NK cells) by the presence of a protein on the B-cell's outer surface called a B-cell receptor (BCR).
    • Describe how T cells and B cells can be differentiated using staining of cell surface receptors and functional assays like the T lymphocyte cytotoxicity assay

  • Antiviral Agents that Prevent Virus Uncoating or Release

    • Virus infection starts with a virus attaching to the host cell by binding to a receptor molecule.
    • Using molecules that will bind to the cell receptor and inactivate it; thus preventing the virus from attachment.
    • Examples include anti-receptor antibodies or natural ligands that can bind to the receptor.
    • Using receptor-like molecules to bind to the virus and inactivate it before it meets the cell.
    • These include anti-virus antibodies (with specificity against the viral structure that binds to the receptor) or synthetic molecules that mimic the receptor.

  • Chemotaxis

    • If one watches a bacterium swimming in a uniform environment, its movement will look like a random walk with relatively straight swims interrupted by random tumbles that reorient it.
    • In other words, bacteria like E. coli use temporal sensing to decide whether their situation is improving or not.
    • Vertebrates seem to have taken advantage of this fact by possessing an immune receptor (TLR5) designed to recognize this conserved protein.
    • These bacteria move by spinning the whole cell, which is shaped like a corkscrew.
    • The proteins CheW and CheA bind to the receptor.

  • General Features of Virus Replication

    • Attachment is a specific binding between viral capsid proteins and specific receptors on the host cellular surface.
    • Its surface protein, gp120, specifically interacts only with the CD4 molecule – a chemokine receptor – which is most commonly found on the surface of CD4+ T-Cells.
    • Attachment to the receptor can fore the viral envelope protein to undergo either changes that result in the fusion of viral and cellular membranes, or changes of non-enveloped virus surface proteins that allow the virus to enter.
    • Virions enter the host cell through receptor-mediated endocytosis or membrane fusion.
    • Bacteria, like plants, have strong cell walls that a virus must breach to infect the cell.

  • Cytotoxic Autoimmune Reactions

    • Three main sets of genes are suspected in many autoimmune diseases: immunoglobulins, T-cell receptors and the major histocompatibility complexes (MHC).
    • Immunoglobulins and the T-cell receptors are involved in the recognition of antigens and they are inherently variable and susceptible to recombination.
    • A few autoimmune diseases that men are just as or more likely to develop as women, include: ankylosing spondylitis, type 1 diabetes mellitus, Wegener's granulomatosis, Crohn's disease, Primary sclerosing cholangitis and psoriasis.
    • HLA-DR is a MHC class II cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21.31.
    • The complex of HLA-DR and its ligand, a peptide of 9 amino acids in length or longer, constitutes a ligand for the T-cell receptor (TCR).

  • The Roles of Genetics and Gender in Autoimmune Disease

    • These genes are related to immunoglobulins, T-cell receptors, and the major histocompatibility complexes (MHC).
    • Immunoglobulins and T-cell receptors are involved in the recognition of antigens and they are inherently variable and susceptible to recombination.
    • A few autoimmune diseases that men are just as or more likely to develop as women, include: ankylosing spondylitis, type 1 diabetes mellitus, Wegener's granulomatosis, and Crohn's disease.
    • HLA-DR is a MHC class II cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21.31.
    • The complex of HLA-DR and its ligand, a peptide of 9 amino acids in length or longer, constitutes a ligand for the T-cell receptor (TCR).