Mast Cells, Eosinophils, and Basophils Overview
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Questions and Answers

Which of the following cells is primarily involved in the immune response to parasites?

  • Eosinophils (correct)
  • Neutrophils
  • Basophils
  • Mast cells

    • Mast cells are circulating cells found in the bloodstream.

    False

    What protective mechanism involves recruitment of leukocytes and extravasation of plasma proteins into infected tissue?

    Inflammation

    Mast cells release __________, which increases vascular permeability.

    <p>histamine</p> Signup and view all the answers

    Match the following cell types with their primary functions:

    <p>Mast cells = Release histamine and involved in allergies Basophils = Release histamine and circulate in the bloodstream Eosinophils = Release inflammatory molecules and respond to parasites Leukocytes = Eliminate infectious agents and mediate inflammation</p> Signup and view all the answers

    What is the primary function of macrophages?

    <p>Phagocytosis</p> Signup and view all the answers

    Toll-like receptors (TLRs) are involved in the recognition of conserved molecular patterns from potentially pathogenic sources.

    <p>True</p> Signup and view all the answers

    What is the primary source of IL-1?

    <p>Macrophages</p> Signup and view all the answers

    Name one type of molecule that TLR2 recognizes.

    <p>Lipoglycans</p> Signup and view all the answers

    Type I interferons are specifically produced by T cells in response to viral infections.

    <p>False</p> Signup and view all the answers

    What is the role of IL-6 in the immune response?

    <p>IL-6 promotes liver synthesis of acute-phase proteins and B cell proliferation.</p> Signup and view all the answers

    The _____ receptor binds to viral envelope proteins and dsRNA.

    <p>TLR3</p> Signup and view all the answers

    Match the following TLRs with the ligands they recognize:

    <p>TLR1 = Lipoproteins TLR2 = Peptidoglycan TLR3 = dsRNA TLR4 = Modified Lipopolysaccharide</p> Signup and view all the answers

    The chemokine CCL11 is primarily responsible for the recruitment of __________.

    <p>eosinophils</p> Signup and view all the answers

    Which of the following is NOT a function of the plasma C-reactive protein?

    <p>Vasodilation</p> Signup and view all the answers

    Match the chemokine to its respective major function:

    <p>CCL2 = Mixed leucocyte recruitment CCL4 = T cell and monocyte recruitment CXCL8 = Neutrophil recruitment CCL19 = T cell and DC migration into lymph nodes</p> Signup and view all the answers

    Which of the following cytokines induces fever?

    <p>IL-1</p> Signup and view all the answers

    Phosphorylcholine is crucial for the activation of macrophage functions.

    <p>True</p> Signup and view all the answers

    What is the role of opsonisation in the immune response?

    <p>Enhances phagocytosis of pathogens</p> Signup and view all the answers

    NLRs are primarily responsible for recognizing bacteria and viral pathogens.

    <p>False</p> Signup and view all the answers

    What does TNF primarily target in the body?

    <p>Endothelial cells, neutrophils, and the hypothalamus.</p> Signup and view all the answers

    The double-stranded RNA pattern is recognized by the __________ in the immune system.

    <p>Toll-like receptor</p> Signup and view all the answers

    What is the main function of IL-12?

    <p>Th1 differentiation</p> Signup and view all the answers

    CX3CL1 is crucial for T cell and NK cell recruitment.

    <p>True</p> Signup and view all the answers

    What does the acronym PAMPs stand for in the context of innate immunity?

    <p>Pathogen-Associated Molecular Patterns</p> Signup and view all the answers

    The chemokine receptor CCR2 is associated with the recruitment of __________.

    <p>Mixed leucocytes</p> Signup and view all the answers

    Match the cytokine to its main source:

    <p>IL-18 = Macrophages IL-10 = Macrophages and T cells IL-15 = Macrophages TNF = Macrophages and T cells</p> Signup and view all the answers

    Which TLR specifically recognizes Lipopolysaccharide (LPS)?

    <p>TLR4</p> Signup and view all the answers

    TLR2 and TLR4 signaling pathways only utilize MyD88-dependent mechanisms.

    <p>False</p> Signup and view all the answers

    What is the role of MyD88 in TLR signaling?

    <p>MyD88 mediates the production of pro-inflammatory cytokines and chemokines.</p> Signup and view all the answers

    TLR4 recognizes ___________ and is associated with the production of pro-inflammatory cytokines.

    <p>LPS</p> Signup and view all the answers

    Match the TLR with its corresponding ligand:

    <p>TLR2 = Mannan TLR4 = Lipid-A TLR6 = Viral envelope proteins TLR1 = Glycoinositolphospholipids</p> Signup and view all the answers

    What is a key feature of MyD88-independent signaling?

    <p>It shares mechanisms with TLR2 signaling.</p> Signup and view all the answers

    Lipid-A is a well-defined ligand for TLR4.

    <p>True</p> Signup and view all the answers

    Identify one role of the NFκB transcription factor in TLR signaling.

    <p>Activates the expression of pro-inflammatory cytokines.</p> Signup and view all the answers

    The proteins __________ are part of the TLR4 signaling pathway.

    <p>IRAK1 and IRAK4</p> Signup and view all the answers

    Which molecule is associated with MyD88-mediated signaling?

    <p>TRAF6</p> Signup and view all the answers

    What is the primary role of defensins in the innate immune system?

    <p>Microbial killing</p> Signup and view all the answers

    Type I interferons are associated with resistance to bacterial infections.

    <p>False</p> Signup and view all the answers

    Name two types of cells that are involved in early phagocytosis of microbes.

    <p>Neutrophils, Macrophages</p> Signup and view all the answers

    The adaptors TRIF and TRAM recruit _____ and protein complexes for signaling after LPS binding.

    <p>TAK1</p> Signup and view all the answers

    Match the following components of the innate immune system with their functions:

    <p>Complement = Killing of microbes and opsonization C-reactive protein = Activation of complement and opsonization Neutrophils = Early phagocytosis and killing of microbes Cytokines = Regulate inflammatory response</p> Signup and view all the answers

    Which of the following cytokines is primarily responsible for inflammation?

    <p>TNF</p> Signup and view all the answers

    Natural Killer (NK) cells can activate macrophages.

    <p>True</p> Signup and view all the answers

    What is the role of mannose-binding lectin in the immune system?

    <p>Opsonization of microbes and activation of complement via lectin pathway.</p> Signup and view all the answers

    IL-12, IL-18, and IL-23 are primarily produced by _____ and T cells.

    <p>NK cells</p> Signup and view all the answers

    Which protein complex is associated with the regulation of inflammation?

    <p>IκBα</p> Signup and view all the answers

    Study Notes

    Mast Cells, Eosinophils, Basophils

    • Mast cells release histamine, increasing vascular permeability and smooth muscle contraction, playing a key role in allergic reactions and being tissue resident.
    • Basophils, which circulate in the blood, also release histamine and are important in the immune response against parasites.
    • Eosinophils release inflammatory molecules and are primarily involved in responses to parasites.

    Inflammation

    • Inflammation is a protective mechanism involving recruitment of leukocytes and plasma proteins to infection sites for pathogen elimination.
    • If inflammation is dysregulated or not resolved promptly, it can lead to tissue damage and pathological conditions.

    Extravasation Process

    • Cytokines and chemokines are secreted at infection sites.
    • Selectins mediate the rolling of leukocytes along the endothelium.
    • Increase in integrin affinity facilitates leukoctye attachment to endothelial cells.
    • Leukocytes then transmigrate through the endothelium to reach the infection site.

    Cytokines Overview

    • TNF (15 kD, 51 kD homotrimer): Produced by macrophages and T cells; activates endothelial cells and neutrophils, induces fever, and promotes catabolism.
    • IL-1 (17 kD): Source includes macrophages; activates endothelial cells, induces fever, and aids gastrointestinal T cell differentiation.
    • IL-12: A heterodimer that promotes Th1 differentiation and activates NK cells for increased IFN-γ synthesis.
    • Type I Interferons (IFN-α and IFN-β): Induce an antiviral state in all cells and activate NK cells.
    • IL-10: Inhibits inflammatory responses in macrophages and dendritic cells, modulating immune responses.
    • IL-6: Induces acute-phase protein synthesis in the liver and helps B cell proliferation.

    Chemokines and Their Functions

    • CCL2 (MCP-1): Attracts mixed leukocytes via CCR2.
    • CCL3 (MIP-1α): Recruits leukocytes using CCR1 and CCR5.
    • CCL4 (MIP-1β): Recruits T cells, dendritic cells, and HIV cores via CCR5.
    • CCL11 (EOTAXIN): Recruits eosinophils through CCR3.
    • CXCL1 (GROα) and CXCL8 (IL-8): Primarily involved in neutrophil recruitment.

    Features of Innate Immunity

    • Recognizes microbial patterns through the expression of receptors such as TLRs (Toll-like receptors) and CLRs (C-type lectin receptors).
    • Major classes include TLRs for bacteria and viruses, CLRs for fungi, NLRs for bacteria and cell damage, and RLRs for viruses.
    • Innate immune receptors are encoded in the germline, allowing rapid response.

    PAMPs/DAMPs and PRRs

    • PAMPs (Pathogen-Associated Molecular Patterns): Recognized by pattern recognition receptors (PRRs) for innate immune response (e.g., dsRNA in viruses).
    • DAMPs (Damage-Associated Molecular Patterns): Indicate tissue damage and can trigger inflammatory responses.
    • Key examples include lipopolysaccharides that activate macrophages and mannose-rich glycans that facilitate phagocytosis.

    TLR Signaling Mechanisms

    • TLR signaling can be MyD88-dependent or independent; MyD88-mediated signaling facilitates pro-inflammatory cytokine production.
    • MyD88-independent pathways are associated with type I interferon responses through adaptors like TRIF and TRAM.
    • TLR4 signaling, for example, is involved in recognizing lipopolysaccharides from Gram-negative bacteria.

    Components of Innate Immunity

    • Epithelial Layers: Prevent pathogen entry.
    • Defensins and Intraepithelial Lymphocytes: Kill microbes effectively.
    • Neutrophils: Provide early phagocytosis and microbial killing.
    • Macrophages: Efficiently phagocytose pathogens and secrete cytokines for inflammation.
    • NK Cells: Lyse infected cells and activate macrophages.
    • Complement System: Opsonizes microbes and activates leukocytes.
    • Cytokines: Such as TNF, IL-1, and interferons play critical roles in inflammation and immune responses.

    Role of Innate Immunity in Adaptive Response

    • Innate immunity is crucial for activating and regulating adaptive immune responses, bridging the two systems for enhanced defense mechanisms.

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    Innate Immunity An Introduction - Dr Alexander Strachan (2024-25).pptx

    Description

    This quiz covers the roles and functions of mast cells, eosinophils, and basophils in the immune response, particularly in relation to allergies and parasitic infections. It highlights the significance of these cells in releasing histamine and other inflammatory molecules. Test your knowledge on these essential immune components!

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