IgE-Mediated Degranulation Process
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Questions and Answers

What initiates IgE-mediated degranulation?

  • Antigen cross-linkage (correct)
  • Mast cell contraction
  • Phosphatase rearrangement
  • IgE binding to the Fc receptor

    • What is necessary for the movement of granules to the plasma membrane during degranulation?

  • Contraction of microfilaments
  • Cooperation among protein and lipid kinases
  • Increase in Ca2+
  • A+C (correct)

    • Which drug is used to block the Ca++ influx as a treatment for allergies?

  • Cromolyn sodium
  • Phosphatase inhibitor
  • Disodium cromoglycate (correct)
  • Cytoskeleton rearranger

    • What is the initial event that triggers IgE-mediated degranulation?

    <p>Cross-linkage of allergen-bound IgE with the Fc receptor on mast cells or basophils</p> Signup and view all the answers

    What is the role of Ca++ influx in mast cell degranulation?

    <p>Promoting the assembly of microtubules and contraction of microfilaments</p> Signup and view all the answers

    What is the result of IgE cross-linkage?

    <p>Mast cell degranulation</p> Signup and view all the answers

    Which intracellular signaling process is involved in initiating mast cell degranulation?

    <p>A+C</p> Signup and view all the answers

    Which process is rearranged during mast cell degranulation?

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

    What are the most significant primary mediators of Type I hypersensitivity?

    <p>Histamine, proteases, eosinophil chemotactic factor, heparin</p> Signup and view all the answers

    Which agents are produced before degranulation and stored in the granules?

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

    When do the primary mediators of Type I hypersensitivity occur?

    <p>2-3 minutes to 6 hours</p> Signup and view all the answers

    What type of agents are synthesized after target-cell activation or released during the degranulation process?

    <p>All of the above</p> Signup and view all the answers

    What is the timing difference between the formation of leukotrienes and prostaglandins compared to histamine?

    <p>Leukotrienes and prostaglandins form after mast cell degranulation, while histamine forms before degranulation</p> Signup and view all the answers

    Which biological effects of leukotrienes and prostaglandins are more pronounced and longer lasting than those of histamine?

    <p>Bronchoconstriction, vascular permeability, mucus production</p> Signup and view all the answers

    Which cytokines are secreted by human mast cells to alter the local microenvironment and recruit inflammatory cells?

    <p>IL-4, IL-5, IL-6, TNF-α</p> Signup and view all the answers

    How does systemic anaphylaxis typically start?

    <p>With sudden skin redness and intense itching and hives</p> Signup and view all the answers

    What is the usual initiation point of systemic anaphylaxis?

    <p>Direct entry of allergen into the bloodstream</p> Signup and view all the answers

    Which of the following symptoms is associated with anaphylactic shock?

    <p>A+B</p> Signup and view all the answers

    What can cause the patient to die of suffocation in systemic anaphylaxis?

    <p>Contraction of smooth muscles due to allergen inhalation</p> Signup and view all the answers

    What is the common name for Allergic Rhinitis?

    <p>Hay fever</p> Signup and view all the answers

    Where does the reaction develop in allergic asthma (extrinsic asthma)?

    <p>Lower respiratory tract</p> Signup and view all the answers

    What is the characteristic symptom of Allergic Rhinitis (hay fever)?

    <p>Watery exudation of conjunctivae</p> Signup and view all the answers

    Immunotherapy involves Desensitization: subcutaneous injections of allergens to cause a shift to IgG production instead of IgE.

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

    How can antibody-bound cells be destroyed in Type II hypersensitivity reactions?

    <p>By activating the complement system and creating pores in the cell membrane</p> Signup and view all the answers

    What is the mechanism of cell destruction in antibody-dependent cell-mediated cytotoxicity (ADCC)?

    <p>Cytotoxic cells bind to the Fc region of antibodies and promote killing of the cells</p> Signup and view all the answers

    What role does opsonization play in Type II hypersensitivity reactions?

    <p>Enabling phagocytic cells to bind and phagocytose the antibody-coated cell</p> Signup and view all the answers

    RBCs have different antigen ,but the most important are A and B antigens(used for blood grouping ABO).

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

    Antibodies to the A, B, and O antigens, called isohemagglutinins, are usually of the IgM class

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

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