Immune System Disorders and Responses
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Questions and Answers

What is the main consequence of immune deficiencies?

  • Enhanced autoimmune responses
  • Heightened risk of infections and certain cancers (correct)
  • Improved response to vaccinations
  • Increased immune sensitivity to allergens

    • Which cells act as the first line of defense against infectious pathogens?

  • T lymphocytes
  • Epithelial cells (correct)
  • B lymphocytes
  • Dendritic cells

    • What is the role of macrophages in the immune response?

  • To mature from monocytes and provide enhanced phagocytosis (correct)
  • To secrete defensins into the bloodstream
  • To produce antibodies against pathogens
  • To activate the complement system exclusively

    • Which of the following is NOT typically considered a component of the normal immune response?

    <p>Natural killer cells in tissue transplants</p> Signup and view all the answers

    What can abnormal protein deposition in tissues lead to?

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

    Which of the following components is part of the innate immune system?

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

    What is a result of overactive immune responses?

    <p>Autoimmune diseases</p> Signup and view all the answers

    In the context of immunity, what are defensins?

    <p>Antimicrobial peptides produced by epithelial cells</p> Signup and view all the answers

    Which category summarizes broader aspects of immunity beyond infectious pathogens?

    <p>Comprehensive immunity</p> Signup and view all the answers

    What are pathogen-associated molecular patterns primarily recognized by?

    <p>Pattern recognition receptors</p> Signup and view all the answers

    Which receptor type is located in the cytosol and recognizes various microbial substances?

    <p>NOD-like receptors</p> Signup and view all the answers

    Which of the following receptors is specifically associated with detecting viral nucleic acids?

    <p>RIG-like receptors</p> Signup and view all the answers

    Damage-associated molecular patterns are released by what type of cells?

    <p>Necrotic or injured cells</p> Signup and view all the answers

    Where are Toll-like receptors (TLRs) primarily located?

    <p>In various cellular compartments</p> Signup and view all the answers

    What type of receptor is primarily responsible for detecting extracellular microbes?

    <p>Plasma membrane receptors</p> Signup and view all the answers

    Inherited loss-of-function mutations affecting which receptors are associated with immunodeficiency syndromes?

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

    What is the primary role of pattern recognition receptors in innate immunity?

    <p>To detect microbial components</p> Signup and view all the answers

    What do RIG-like receptors (RLRs) primarily recognize?

    <p>Viral nucleic acids</p> Signup and view all the answers

    What type of receptors detect endocytosed microbes?

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

    What is the primary function of MHC molecules in the immune system?

    <p>To display peptide fragments for T cell recognition</p> Signup and view all the answers

    Where do plasma cells primarily reside within the immune system?

    <p>In secondary lymphoid organs and bone marrow</p> Signup and view all the answers

    Which class of MHC molecules is expressed on all nucleated cells?

    <p>Class I MHC molecules</p> Signup and view all the answers

    What characteristic is shared by the α chains of Class I MHC molecules?

    <p>They are encoded by multiple closely located genes</p> Signup and view all the answers

    What is the role of effector T cells in response to infection?

    <p>To circulate and migrate to sites of infection to eliminate microbes</p> Signup and view all the answers

    What role do inhibitory receptors play in the function of NK cells?

    <p>They prevent NK cells from attacking healthy cells.</p> Signup and view all the answers

    What is the significance of the α1 and α2 domains of the Class I MHC molecule?

    <p>They create a groove for peptide binding.</p> Signup and view all the answers

    What characterizes naïve lymphocytes?

    <p>They have not encountered the antigen for which they are specific.</p> Signup and view all the answers

    Which statement about class I MHC expression in infected cells is true?

    <p>Class I MHC expression is reduced, preventing inhibition of NK cells.</p> Signup and view all the answers

    What are the two main types of cells that mature lymphocytes differentiate into after activation?

    <p>Effector cells and memory cells.</p> Signup and view all the answers

    What is the role of danger signals in the immune response?

    <p>They stimulate the subsequent adaptive immune response.</p> Signup and view all the answers

    What is indicated by the term 'antiviral state' in the context of lymphocytes?

    <p>Lymphocytes produce enzymes that fight viral replication.</p> Signup and view all the answers

    Which of the following statements about the interaction of lymphocytes is correct?

    <p>Lymphocytes are anatomically segregated and interact only upon stimulation.</p> Signup and view all the answers

    How does the recognition of antigens influence lymphocyte function?

    <p>It leads to activation and eventual differentiation into effector and memory cells.</p> Signup and view all the answers

    What happens to the class I MHC molecules on healthy cells in relation to NK cell activity?

    <p>They prevent NK cells from recognizing healthy cells.</p> Signup and view all the answers

    What is the importance of memory cells in the immune response?

    <p>They remain inactive until a second exposure to an antigen.</p> Signup and view all the answers

    What is the primary role of dendritic cells (DCs) in the immune response?

    <p>To transport antigens from epithelia to lymph nodes.</p> Signup and view all the answers

    What feature of lymph nodes aids in the concentration of antigens?

    <p>The nodular aggregation of lymphoid tissues.</p> Signup and view all the answers

    Which of the following statements is accurate about the spleen's function?

    <p>It traps blood-borne antigens to initiate immune responses.</p> Signup and view all the answers

    Where are naïve lymphocytes primarily located before they encounter antigens?

    <p>In lymphatic channels and peripheral tissues.</p> Signup and view all the answers

    What triggers the activation of adaptive immune responses in lymph nodes?

    <p>The direct contact of lymphocytes with antigens captured by antigen-presenting cells.</p> Signup and view all the answers

    What is the significance of the epithelial surfaces in relation to antigen entry?

    <p>They are common sites for pathogen entry into the body.</p> Signup and view all the answers

    How do lymph nodes primarily contribute to adaptive immunity?

    <p>By concentrating foreign antigens for lymphocyte activation.</p> Signup and view all the answers

    What type of antigens do lymph nodes primarily respond to?

    <p>Antigens derived from microbes entering through epithelia.</p> Signup and view all the answers

    Which cells are involved in capturing antigens within the spleen?

    <p>Macrophages and dendritic cells.</p> Signup and view all the answers

    What is the primary function of naïve lymphocytes in the immune system?

    <p>To recognize and respond to specific antigens.</p> Signup and view all the answers

    Study Notes

    Immune System Disorders

    • Immune deficiencies: lead to increased susceptibility to infections and cancer.
    • Autoimmunity: occurs when the immune system mistakenly attacks the body's own tissues.
    • Amyloidosis: involves abnormal protein deposition (often derived from immunoglobulins) in various tissues.

    The Normal Immune Response

    • Immunity: Protection from infectious pathogens, cancers, tissue transplants, and self-antigens (autoimmunity).
    • Normal immune Response: Best understood in the context of protection from infectious pathogens.
    • Two major mechanisms of immunity:
      • Innate immunity: Immediate, non-specific response.
      • Adaptive immunity: Slower, specific response.
    • Innate immunity:
      • First line of defense: Skin, mucous membranes, antimicrobial molecules like defensins.
      • Cellular components: Phagocytes (neutrophils, macrophages), dendritic cells, natural killer (NK) cells.
      • Plasma proteins: Complement system.
    • Pattern recognition receptors (PRRs):
      • Present on phagocytes, dendritic cells, and epithelial cells。
      • Detect pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs).
      • Examples of PRRs:
        • Toll-like receptors (TLRs): Recognize various microbial products.
        • NOD-like receptors (NLRs): Recognize products from necrotic cells and microbes.
        • C-type lectin receptors (CLRs): Recognize carbohydrates on microbes.
        • RIG-like receptors (RLRs): Detect viral nucleic acids.
        • Cytosolic DNA receptors: Detect foreign DNA.
    • NK cells:
      • Kill virus-infected cells and tumor cells.
      • Recognize cells with reduced MHC class I expression.
      • Express activating and inhibitory receptors that recognize ligands on target cells.
      • Trigger release of cytotoxic granules that kill target cells.
    • Interferons:
      • Antiviral cytokines produced by infected cells.
      • Induce an antiviral state in neighboring cells.
      • Signal the immune system to fight viral infections.
      • Can also activate macrophages to kill infected cells.
    • Inflammation:
      • A complex response involving vascular changes, leukocyte recruitment, and tissue repair.
      • Initiated by PRRs and other inflammatory mediators.
      • A vital protective mechanism but can sometimes become detrimental, leading to chronic inflammation.
    • Adaptive immunity:
      • Specific and targeted response.
      • Mediated by lymphocytes (T cells and B cells).
      • Involves the recognition of specific antigens.
      • Lymphocyte diversity: Wide range of lymphocytes specific for different antigens.
      • Naïve lymphocytes: Lymphocytes that have not yet encountered their specific antigen.
      • Effector lymphocytes: Lymphocytes that have been activated and can directly kill target cells or produce antibodies.
      • Memory lymphocytes: Lymphocytes that remember specific antigens and can respond more quickly and effectively upon re-exposure.
    • Secondary lymphoid organs:
      • Lymph nodes and the spleen.
      • Sites of adaptive immune response generation.
      • Concentrate antigens and lymphocytes to facilitate their interaction.
      • Lymph nodes: Receive antigens from tissues via lymphatic vessels.
      • Spleen: Receive antigens from blood.
      • Lymphocyte trafficking:
        • Naïve lymphocytes circulate through secondary lymphoid organs searching for antigens.
        • Effector lymphocytes migrate to sites of infection.
    • Major Histocompatibility Complex (MHC)
      • MHC molecules are involved in presenting peptide fragments of antigens to lymphocytes.
      • MHC class I molecules:
        • Present on all nucleated cells.
        • Display peptides from intracellular proteins, including viral proteins.
        • Recognized by CD8+ T cells.
      • MHC class II molecules:
        • Present on antigen-presenting cells (APCs).
        • Display peptides from extracellular proteins, such as microbial proteins.
        • Recognized by CD4+ T cells.
    • T and B cells:
      • T cells:
        • Mature in the thymus.
        • Recognize antigen presented by MHC molecules.
        • CD4+ T cells: Helper T cells that activate other immune cells.
        • CD8+ T cells: Cytotoxic T cells that kill infected or cancerous cells.
      • B cells:
        • Mature in the bone marrow.
        • Recognize native antigen (not presented by MHCs)
        • Differentiate into plasma cells, which secrete antibodies.
    • Antibody-mediated immunity:
      • Involves antibodies secreted by B cells.
      • Antibodies bind to antigens, leading to their neutralization, opsonization, or complement activation.

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    Description

    Explore the intricacies of immune system disorders such as autoimmunity, immune deficiencies, and amyloidosis. This quiz also covers the mechanisms of normal immune responses, including innate and adaptive immunity. Test your understanding of how the immune system protects against infections and its role in various disorders.

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