Immunology Overview Quiz
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Immunology Overview Quiz

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Questions and Answers

What is the main function of lysosomes in the immune system?

  • Production of antibodies
  • Activation of T cells
  • Breaking down fungi (correct)
  • Transport of immune cells

    • Which characteristic distinguishes acquired immunity from innate immunity?

  • Presence of leukocytes
  • Production of cytokines
  • Memory and specificity (correct)
  • Immediate response

    • What cells does MHC I present antigens to?

  • B cells
  • Neutrophils
  • CD8 T cells (correct)
  • CD4 T cells

    • What is the role of C5a in the immune response?

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

    Which immunoglobulin is known to provide protection to infants by crossing the placenta?

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

    Which immunoglobulin is primarily found in breast milk and exists in a dimeric form?

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

    What is the primary activator of the classical pathway of complement activation?

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

    What component is essential for the formation of C5 convertase?

    <p>C3b</p> Signup and view all the answers

    What is the primary function of cytotoxic T cells?

    <p>Killing virus-infected cells</p> Signup and view all the answers

    What form does IgM take when functioning as a receptor on B Cells?

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

    When is IgM produced as soluble pentamers?

    <p>When mediating host defenses</p> Signup and view all the answers

    Which type of hypersensitivity is associated with IgE?

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

    What is a notable enzyme released by eosinophils that assists in limiting allergic reactions?

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

    What is the primary function of haptens in the context of drug hypersensitivity?

    <p>To elicit an immune response only when combined with a protein</p> Signup and view all the answers

    Which drug is commonly associated with drug hypersensitivity reactions?

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

    What is an anaphylactoid reaction?

    <p>An immune response that does not involve IgE</p> Signup and view all the answers

    Which condition is caused by the cross-reaction of antibodies with cardiac antigens?

    <p>Rheumatic Fever</p> Signup and view all the answers

    What is the Rheumatoid Factor?

    <p>IgG and IgM bound to the Fc fragment of IgG</p> Signup and view all the answers

    What is the primary consequence of the absence of co-stimulation (B7 to CD28 interaction) in T Cells?

    <p>Anergic T Cells</p> Signup and view all the answers

    In Poststreptococcus Glomerulonephritis (PSGN), what type of hypersensitivity occurs?

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

    Which cells are primarily responsible for innate immunity?

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

    What is a key characteristic of Tuberculoid Leprosy?

    <p>TH1 and cell-mediated immunity is intact</p> Signup and view all the answers

    What happens to a T Cell when CTLA-4 binds to B7?

    <p>The T Cell undergoes apoptosis</p> Signup and view all the answers

    How does Mycobacterium Tuberculosis evade destruction by innate immune cells?

    <p>By inhibiting phagolysosome fusion</p> Signup and view all the answers

    What is the primary function of NK Cells?

    <p>Surveillance for cancer cells</p> Signup and view all the answers

    What process describes Ab-Dependent Cellular Toxicity (ADCC)?

    <p>Activation of NK cells to kill Ab-coated target cells</p> Signup and view all the answers

    What is DiGeorge Syndrome associated with?

    <p>Absence of the thymus</p> Signup and view all the answers

    Which cells are primarily responsible for producing histamine?

    <p>Basophils and mast cells</p> Signup and view all the answers

    What does SCID stand for?

    <p>Severe Combined Immunodeficiency</p> Signup and view all the answers

    What is a committed B cell primarily characterized by?

    <p>Recognition of specific antigens and binding to them</p> Signup and view all the answers

    Which combination represents a chimeric monoclonal antibody?

    <p>Fc from human, Fab from mouse</p> Signup and view all the answers

    What type of immunity is induced by vaccination?

    <p>Active immunization</p> Signup and view all the answers

    How can the side effects of chemotherapy be minimized with monoclonal antibodies?

    <p>Conjugate an enzyme for local activation</p> Signup and view all the answers

    What process involves PMNs leaving blood circulation to enter surrounding tissues?

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

    What does IL-2 signaling in T Cells primarily lead to?

    <p>Activation and proliferation of T Cells</p> Signup and view all the answers

    What is the primary target antigen in Graves Disease?

    <p>Thyroid Stimulating Hormone (TSH)</p> Signup and view all the answers

    What role does IgG play in the immune system?

    <p>Functions primarily as an opsonin</p> Signup and view all the answers

    What is the consequence of a deficiency in extravasation related to selectins and integrins?

    <p>Reduced leukocyte migration to sites of infection</p> Signup and view all the answers

    Which immunoglobulin is most effective in protecting mucosal surfaces?

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

    What defect does a patient with Mycobacterium Lepra most likely have?

    <p>TH1 deficiency</p> Signup and view all the answers

    What is the immunological significance of IgD?

    <p>It has no effector function</p> Signup and view all the answers

    Which type of T Cell requires MHC II for interaction?

    <p>Helper T Cell</p> Signup and view all the answers

    What is affinity maturation primarily driven by?

    <p>Mutations in the heavy and light chain variable regions</p> Signup and view all the answers

    What happens in Transient Myasthenia Gravis?

    <p>Neonates acquire IgG antibodies from the mother</p> Signup and view all the answers

    In the context of B Cells and their interactions, what does MHC I Restriction refer to?

    <p>Interaction with Cytotoxic T Cells</p> Signup and view all the answers

    Study Notes

    Hematopoiesis

    • Occurs in bone marrow
    • The process of making white blood cells (WBCs)

    Lysosomes

    • Part of innate immunity
    • Found in some body fluids and cells (e.g., eye)
    • Function: break down fungi

    Innate vs. Acquired Immunity

    • Innate Immunity: No memory or specificity
    • Acquired Immunity: Has memory and specificity

    Cytotoxic T Cells

    • CD8+ cells that recognize antigens presented by MHC I
    • Kill intracellular bacteria and cancer cells

    MHC I

    • Found on all nucleated cells
    • Presents antigens to cytotoxic T cells (CD8+)
    • MHC I restriction: CD8+ T cells only recognize MHC I

    Ill Effects of the Immune System

    • Hypersensitivity
    • Graft rejection
    • Autoimmunity

    Fas and FasL (Death Receptors)

    • Role: induce apoptosis in T cells
    • Trigger programmed cell death

    C5a

    • Function:
      • Attract neutrophils (chemotaxis)
      • Anaphylatoxic (triggers inflammatory response)

    Complement System: End Product

    • Membrane Attack Complex (MAC): C5b678(C9)6

    C3 Convertase

    • Alternative Pathway: C3bBb
    • Classical Pathway: C4b2a
    • Activation: Requires C3b to form C5 convertase

    Classical Pathway Activators

    • IgG
    • IgM

    IgG

    • Function: Opsonin (enhances phagocytosis)
    • Feedback inhibition: prevents B cells from producing antibodies and binding to antigens
    • Crosses the placenta: provides protection to the fetus

    Opsonins

    • Innate Immunity:
      • C3b
      • C4b (Complement)
      • CRP (produced by hepatocytes)
    • Acquired Immunity: IgG

    IgA

    • Found in breast milk
    • Dimeric structure

    IgD and IgM as B Cell Receptors

    • IgD: B cell receptor (BCR)
    • IgM: When acting as a BCR, it exists as a monomer. As an effector, it is pentameric

    IgM: Pentamer

    • Function: mediates host defenses against invading pathogens
    • Produced by plasma cells and secreted as soluble pentamers

    IgE and Eosinophils

    • Antiparasitic: IgE + eosinophils
    • Eosinophil Functions:
      • Histaminase: limits severity of allergic reactions
      • Arylsulfatase: degrades SRS-A (slow-reacting substance of anaphylaxis), limiting allergic reactions
      • Chemotactic factor

    Type I Hypersensitivity

    • Immediate type hypersensitivity
    • Mediated by IgE
    • Penicillins (PCN):
      • Act as haptens (small molecules that become immunogenic when bound to larger molecules)
      • Can bind to surface proteins on red blood cells (RBCs)

    Anaphylactoid Reactions

    • Non-IgE mediated.
    • Similar effects to anaphylactic reactions but without IgE involvement
    • Induced by certain drugs

    Rheumatic Fever vs. Poststreptococcal Glomerulonephritis (PSGN)

    • Rheumatic Fever:
      • Type II hypersensitivity (autoimmune disease)
      • Antibody-mediated
      • Antibodies against Streptococcus A cross-react with cardiac antigens, leading to rheumatic fever
      • Antigens and antibodies already circulating
    • PSGN:
      • Type II hypersensitivity (immune complex hypersensitivity)
      • Antigen-antibody complexes cause an inflammatory response

    Rheumatoid Factor

    • IgG and IgM antibodies bound to the Fc fragment of normal IgG
    • Used to diagnose rheumatoid diseases

    T Cell Activation - Co-stimulation

    • Normal response: B7 binds to CD28, leading to IL-2 production and activation of naive T cells
    • Anergy (Lack of Co-stimulation):
      • B7 does not bind CD28
      • T cell does not activate and becomes anergic (unable to respond to antigens)
    • CTLA-4 Engagement:
      • CTLA-4 on T cells binds B7
      • No IL-2 production
      • T cell does not activate and dies

    Anergy

    • Lymphocytes that are unable to respond to antigens or allergens

    LAK Cells

    • Lymphokine-activated killer cells
    • NK cells activated with IL-2

    NK Cells

    • Part of innate immunity
    • Function: surveillance for cancer cells
    • Can kill cells without MHC I recognition

    Lymphocyte Types

    • Innate Immunity: NK cells
    • Acquired Immunity: B cells and T cells

    Severe Combined Immunodeficiency (SCID)

    • ADA Deficiency (Adenosine Deaminase Deficiency):
      • Leads to SCID
    • Deficiency in the Gamma Chain of IL-7 Receptor:
      • Inhibits T cell development
      • X-linked, affecting males more severely

    DiGeorge Syndrome

    • Absence of thymus at birth

    Chimeric Monoclonal Antibodies

    • Contain both human and mouse components:
      • Fc part from human
      • Fab portion from mouse
    • Aim: reduce adverse immune effects by minimizing differences between human and mouse antibodies

    Magic Bullet

    • Monoclonal antibody (mAb) conjugated with ricin (a toxin)
    • Targets and kills specific cells

    Reducing Chemotherapy Side Effects with mAbs

    • Conjugate an enzyme that activates an inactive pro-drug at the cancer site

    Extravasation

    • Polymorphonuclear leukocytes (PMNs) leaving the bloodstream through the endothelium into surrounding tissues
    • Deficiencies: can occur due to defects in selectins and integrins

    Graves Disease (Hyperthyroidism)

    • Autoimmune disease
    • Antibodies target the thyroid-stimulating hormone (TSH) receptor
    • Causes hyperthyroidism (excess thyroid hormone production)

    Myasthenia Gravis (MG)

    • IgG antibodies attack acetylcholine receptors (AChR)
    • Inhibits acetylcholine binding to the receptor, leading to muscle weakness

    Transient Myasthenia Gravis (MG)

    • IgG antibodies cross the placenta and cause temporary MG in infants

    Spleen Function

    • Important for defense against encapsulated bacteria
    • Facilitates antibody-mediated phagocytosis

    Affinity Maturation

    • Increase in antibody affinity with repeated exposure to antigens
    • Occurs due to mutations in the variable regions of light and heavy chains

    IgA: Mucosal Surface Protection

    • Monomer in serum
    • Dimer in mucosal secretions (e.g., breast milk)

    IgD

    • No effector function
    • Acts as a B cell receptor (BCR)

    Feedback Inhibition

    • IgG has feedback inhibition, preventing further antibody production and B cell activation

    Opsonization

    • IgG is an opsonin

    MHC Restriction

    • B Cell and T Helper (TH2) Cell Interaction: MHC II restriction
    • B Cell and Cytotoxic T Cell Interaction: MHC I restriction

    Mycobacterium Lepra

    • TH1 Deficiency: Individuals with a TH1 deficiency are more susceptible to the severe form of leprosy
    • Forms:
      • Tuberculoid Leprosy (Mild): TH1 and cell-mediated immunity intact
      • Lepromatous Leprosy (Severe): TH1 deficiency, impaired cell-mediated immunity

    Mycobacterium Tuberculosis (Mtb)

    • Intracellular pathogen that lives inside macrophages
    • Evades killing by inhibiting phagolysosome fusion (using "cord factor")

    ADCC (Antibody-Dependent Cellular Cytotoxicity)

    • NK cells kill target cells coated with antibodies (Ab-coated cells)
    • Requires antibody binding to facilitate targeting
    • Similar to opsonization and phagocytosis

    Histamine Producing Cells

    • Basophils: found in blood
    • Mast cells: found in tissues

    Neutrophils

    • Part of innate immunity
    • Major phagocytes
    • Most abundant type of white blood cell

    C3bBb

    • Alternative pathway C3 convertase
    • Cleaves C3 into C3a and C3b

    Committed B Cells

    • B cells that have bound to a specific antigen and are committed to producing antibodies against that antigen
    • Ag-independent differentiation

    Natural Defense Mechanisms

    • Acidic pH of the stomach
    • Skin
    • Lysozyme
    • Microflora
    • Enzymes

    Graft vs. Host Disease (GvHD)

    • Graft cells (immunocompetent) attack the host (immunocompromised)
    • Often occurs after bone marrow transplantation

    Active Immunization

    • Vaccination
    • Induces the immune system to produce an immune response

    Acute Desensitization

    • Not described in the provided information.
    • It is related to treating allergic reactions by gradually increasing the dose of the allergen.

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    Description

    Test your knowledge on key concepts of immunology, including hematopoiesis, innate vs. acquired immunity, and the role of T cells. This quiz covers important topics like lysosomes, the complement system, and immune response mechanisms. Ideal for students studying advanced biology or immunology.

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