Immune Response and Hypersensitivity
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Questions and Answers

What is the process by which circulating cells become targets for phagocytosis by neutrophils and macrophages?

  • Opsonization with autoantibodies and complement proteins (correct)
  • Formation of immune complexes with exogenous antigens
  • Activation of the complement system by the alternative pathway
  • Phagocytosis of cells by antibody-mediated cellular dysfunction

    • What is the primary function of products of complement activation in inflammation?

  • To recruit neutrophils and monocytes, triggering inflammation (correct)
  • To activate the alternative pathway of complement activation
  • To form immune complexes with endogenous antigens
  • To impair cellular function without causing cell injury or inflammation

    • What is an example of antibody-mediated cellular dysfunction?

  • Rheumatoid arthritis, where immune complexes deposit in joints
  • Lupus, where immune complexes deposit in the kidneys
  • Myasthenia gravis, where antibodies against acetylcholine receptors impair neuromuscular transmission (correct)
  • Type I hypersensitivity, where IgE antibodies trigger an allergic response

    • What is the condition under which immune complexes are pathogenic?

    <p>When formed in large amounts, persist, and are deposited in tissues</p> Signup and view all the answers

    What is the term for the type of hypersensitivity characterized by immune complex-mediated injury?

    <p>Type III hypersensitivity</p> Signup and view all the answers

    What is the term used to describe an immune response that results in exaggerated or inappropriate reactions harmful to the host?

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

    What is the outcome of immune complex-mediated injury when complexes are formed and deposited in a specific site?

    <p>Localized injury to a specific organ</p> Signup and view all the answers

    What is the type of hypersensitivity reaction that occurs within minutes of exposure to an antigen?

    <p>Type I hypersensitivity</p> Signup and view all the answers

    What is the term used to describe the movement of WBC's in response to chemical attractants?

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

    What is the result of an immune response to microbial antigens that triggers inflammation in tissues?

    <p>Immune complexes</p> Signup and view all the answers

    What is the type of hypersensitivity disease caused by antibodies directed against target antigens on the surface of cells or other tissue components?

    <p>Type II hypersensitivity</p> Signup and view all the answers

    What is the second phase of the pathogenesis of systemic immune complex disease?

    <p>Deposition of immune complexes in various tissues</p> Signup and view all the answers

    What is the term used to describe the failure of self-tolerance leading to an immune response against an individual's own antigens?

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

    What is the type of hypersensitivity reaction that occurs in response to environmental antigens such as pollens, animal danders, and dust?

    <p>Reaction against environmental antigens</p> Signup and view all the answers

    What type of T cells are responsible for cytokine-mediated inflammation?

    <p>CD4+ T cells</p> Signup and view all the answers

    What is the clinical manifestation of a severe, systemic, and potentially life-threatening allergic reaction?

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

    Which of the following diseases is NOT caused by TH1 and TH17 reactions against self-antigens?

    <p>Rheumatoid arthritis</p> Signup and view all the answers

    What is the main function of cytokines produced by CD4+ T cells?

    <p>To recruit and activate macrophages</p> Signup and view all the answers

    What type of T cells are responsible for direct cell cytotoxicity?

    <p>CD8+ T cells</p> Signup and view all the answers

    What is the term for the type of hypersensitivity reaction caused by T cells?

    <p>Type IV hypersensitivity</p> Signup and view all the answers

    What is the name of the type of T cell reaction that involves the secretion of cytokines?

    <p>Delayed-type hypersensitivity</p> Signup and view all the answers

    What is the term for the cells that are the major effector cells of injury in cytokine-mediated inflammation?

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

    Which autoimmune disease is characterized by the production of a large number of autoantibodies that can damage tissues?

    <p>Systemic Lupus Erythematosus</p> Signup and view all the answers

    What is the underlying cause of the breakdown in self-tolerance in Systemic Lupus Erythematosus?

    <p>Unknown, but may include excess or persistence of nuclear antigens</p> Signup and view all the answers

    Which of the following is NOT a manifestation of Systemic Lupus Erythematosus?

    <p>Cardiac infarction</p> Signup and view all the answers

    What is the primary characteristic of Rheumatoid Arthritis?

    <p>Nonsuppurative proliferative synovitis</p> Signup and view all the answers

    What is the term used to describe the secondary form of Sjögren syndrome?

    <p>Sicca syndrome</p> Signup and view all the answers

    Which of the following is an environmental factor that may contribute to the development of Systemic Lupus Erythematosus?

    <p>UV radiation</p> Signup and view all the answers

    Which autoimmune disease is characterized by immune-mediated destruction of the lacrimal and salivary glands?

    <p>Sjögren syndrome</p> Signup and view all the answers

    Which of the following organs is NOT typically affected by Systemic Lupus Erythematosus?

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

    What is the primary mechanism by which microbes trigger autoimmunity?

    <p>By sharing cross-reacting epitopes with self antigens</p> Signup and view all the answers

    Which of the following is a risk factor for rheumatoid arthritis (RA)?

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

    What is the term for the phenomenon where an immune response against a microbe cross-reacts with self tissues?

    <p>Molecular mimicry</p> Signup and view all the answers

    Which of the following is a characteristic of autoimmune diseases?

    <p>They can be caused by different types of immune reactions</p> Signup and view all the answers

    What is the result of local tissue injury in terms of autoimmune responses?

    <p>The release of self antigens and autoimmune responses</p> Signup and view all the answers

    Which of the following is NOT a mechanism by which microbes trigger autoimmunity?

    <p>Direct activation of autoimmune T cells</p> Signup and view all the answers

    What is the term for the immune response against self antigens?

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

    What is a characteristic of autoimmune diseases in terms of gender?

    <p>They are more common in women than in men</p> Signup and view all the answers

    Study Notes

    Chemotaxis and Inflammation

    • Chemotaxis is the movement of WBCs in response to chemical attractants
    • During inflammation, WBCs, dead tissue, and bacterial cells accumulate, forming pus
    • Inflammatory exudate becomes thick with WBCs, leading to tissue damage

    Hypersensitivity

    • Hypersensitivity is an exaggerated or inappropriate immune response that harms the host
    • Causes of hypersensitivity:
      • Autoimmunity: failure of self-tolerance
      • Reaction against microbes: excessive reactions or persistent antigens
      • Reaction against environmental antigens: pollens, animal danders, dust

    Types of Hypersensitivity Diseases

    • Immediate (Type I) Hypersensitivity:
      • Rapid immune reaction within minutes
      • Interaction of antigen and IgE antibody on mast cells in sensitized hosts
      • Examples: seasonal rhinitis, hay fever, asthma, anaphylaxis
    • Antibody-Mediated Diseases (Type II Hypersensitivity):
      • Caused by antibodies directed against target antigens on cells or tissue components
      • Mechanisms:
        • Opsonization and phagocytosis
        • Inflammation
        • Antibody-mediated cellular dysfunction
      • Examples: myasthenia gravis, autoimmune hemolytic anemia
    • Immune Complex Diseases (Type III Hypersensitivity):
      • Antigen-antibody complexes formed in the circulation deposit in blood vessels, leading to complement activation and inflammation
      • Examples: poststreptococcal glomerulonephritis, systemic lupus erythematosus
    • T Cell-Mediated (Type IV) Hypersensitivity:
      • Caused by T cells, leading to tissue injury and disease
      • Mechanisms:
        • Cytokine-mediated inflammation
        • Direct cell cytotoxicity
      • Examples: autoimmune disorders, pathologic reactions to environmental chemicals and persistent microbes

    Autoimmunity

    • Definition: immune response against self (auto-) antigens, resulting in tissue damage
    • General principles:
      • Pathogenesis: combination of susceptibility genes and environmental triggers
      • Different autoimmune diseases may be systemic or organ-specific
    • Triggers:
      • Microbes (bacteria, viruses, mycoplasmas) through molecular mimicry
      • Environmental insults (UV radiation, smoking)
      • Family history and genetic polymorphisms

    Autoimmune Diseases

    • Systemic Lupus Erythematosus (SLE):
      • Fundamental defect: production of autoantibodies that can damage tissues
      • Disease manifestations: nephritis, skin lesions, arthritis, hematologic and neurologic abnormalities
      • Unknown underlying cause: excess or persistence of nuclear antigens, genetic factors, environmental factors
    • Rheumatoid Arthritis (RA):
      • Systemic, chronic inflammatory disease affecting many tissues, primarily joints
      • Produces nonsuppurative proliferative synovitis, leading to articular cartilage and bone destruction
    • Sjögren Syndrome:
      • Clinicopathologic entity characterized by dry eyes and dry mouth
      • Resulting from immune-mediated destruction of lacrimal and salivary glands
      • Primary form (sicca syndrome) or secondary form (associated with another autoimmune disease)

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    Description

    This quiz covers the movement of white blood cells in response to chemical attractants, the formation of pus, and hypersensitivity reactions, including autoimmune responses.

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