chapter 14 Cell-Mediated Effector Responses Quiz
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Questions and Answers

What is the principal role of cell-mediated immunity?

  • To express antigens not typical of normal cells
  • To detect and eliminate cells that harbor intracellular pathogens (correct)
  • To mediate delayed-type hypersensitivity
  • To produce secreted antibodies

    • Which of the following is correct cells specific cell-mediated immune response?

  • Neutrophils
  • CD8+ cytotoxic T lymphocytes (TC cells or CTLs) (correct)
  • NK cells
  • Macrophages

    • Which of the following is Correct nonspecific cells in cell-mediated immunity ?

  • CD8+ cytotoxic T lymphocytes (TC cells or CTLs)
  • CD4+ TH cells
  • Cytokine-secreting CD4+ TH cells
  • NK cells (correct)

    • What are the effectors of the humoral branch?

    <p>Secreted antibodies</p> Signup and view all the answers

    Cell-mediated immunity can recognize and eliminate tumor cells with modified antigens.

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

    Macrophages are specific cells that contribute to the cell-mediated immune response.

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

    Cytotoxic T lymphocytes (CTLs) are antigen-nonspecific cells in the cell-mediated immune response.

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

    The effectors of the humoral branch are secreted antibodies that can neutralize antigens on the surface of cells.

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

    Which effector cells can be grouped into two general categories based on cytotoxic activity?

    <p>Antigen-specific cytotoxic T lymphocytes (CTLs) and nonspecific cells</p> Signup and view all the answers

    Which subpopulation of effector cells mediates delayed-type hypersensitivity reactions?

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

    What type of cells are included as nonspecific cells in the cell-mediated immune response?

    <p>Natural killer (NK) cells and macrophages</p> Signup and view all the answers

    In cell-mediated immune responses, which effector population directly exhibits cytotoxic activity?

    <p>Cytotoxic T lymphocytes (CTLs)</p> Signup and view all the answers

    Effector cells that have direct cytotoxic activity include antigen-specific cytotoxic T lymphocytes (CTLs) and nonspecific cells such as natural killer (NK) cells and macrophages.

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

    Effector CD4+ T cells mediate immediate-type hypersensitivity reactions(DTH) in cell-mediated immune responses.

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

    What is the principal role of cytotoxic T lymphocytes (CTLs)?

    <p>Recognizing and eliminating altered self-cells</p> Signup and view all the answers

    Which type of major histocompatibility complex (MHC) is recognized by cytotoxic T lymphocytes (CTLs)?

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

    What is the primary function of effector cytotoxic T lymphocytes (CTLs)?

    <p>Recognizing and destroying specific target cells</p> Signup and view all the answers

    What characterizes the CTL-mediated immune response?

    <p>It activates and differentiates naive TC cells into functional effector CTLs</p> Signup and view all the answers

    Cytotoxic T lymphocytes (CTLs) are generated by immune activation of T cytotoxic (TC) cells.

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

    CTLs are CD4+ and are therefore class I MHC restricted.

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

    Effector CTLs recognize and eliminate altered self-cells, such as virus-infected cells and tumor cells.

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

    Effector CTLs mediate immediate-type hypersensitivity reactions (DTH) in cell-mediated immune responses.

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

    What is the primary function of effector cytotoxic T lymphocytes (CTLs)?

    <p>Recognizing and eliminating altered self-cells, such as virus-infected cells and tumor cells</p> Signup and view all the answers

    Which subpopulation of effector cells mediates delayed-type hypersensitivity reactions?

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

    What characterizes the CTL-mediated immune response?

    <p>Recognizing and eliminating altered self-cells only</p> Signup and view all the answers

    What are the effectors of the humoral branch?

    <p>Secreted antibodies that can neutralize antigens on the surface of cells</p> Signup and view all the answers

    Naive TC cells are capable of killing target cells.

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

    The generation of CTLs from CTL-Ps requires at least three sequential signals.

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

    Effector CTLs recognize and eliminate altered self-cells, such as virus-infected cells and tumor cells.

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

    Effector CD4+ T cells mediate immediate-type hypersensitivity reactions in cell-mediated immune responses.

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

    What is the primary event in CTL-mediated death?

    <p>Conjugate formation</p> Signup and view all the answers

    Which proteins are important for cytolysis in CTL-mediated death?

    <p>Perforin and granzymes</p> Signup and view all the answers

    What happens to the CTL granules during CTL-mediated death?

    <p>Reorient towards the point of contact with the target cell</p> Signup and view all the answers

    After dissociation of the conjugate, what happens to the CTL?

    <p>It is recycled</p> Signup and view all the answers

    CTL-mediated death involves conjugate formation, membrane attack, CTL dissociation, and target cell destruction.

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

    T-cell receptors on a CTL interact with processed antigen-class II MHC complexes on an appropriate target cell.

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

    The granule proteins important for cytolysis in CTL-mediated death are perforin and granzymes.

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

    After dissociation of the conjugate, the CTL is discarded and the target cell dies by necrosis.

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

    What is the primary role of perforin in CTL-mediated cell death?

    <p>Forming pores in the target cell membrane to allow entry of water and ions</p> Signup and view all the answers

    What do granzymes do in CTL-mediated cell death?

    <p>Enter target cells through perforin pores and induce target cell apoptosis</p> Signup and view all the answers

    What is the function of Fas ligands (FasL) in CTL-mediated cell death?

    <p>Inducing target cell apoptosis</p> Signup and view all the answers

    What characterizes the apoptosis called apoptosis by osmotic lysis of cell in CTL-mediated cell death?

    <p>Both 1+2 mechanisms</p> Signup and view all the answers

    What is the primary function of natural killer (NK) cells?

    <p>Controlling viral replication and tumor cells</p> Signup and view all the answers

    Which cytokines stimulate natural killer (NK) cell activity?

    <p>IFN-α, IFN-β, and IL-12</p> Signup and view all the answers

    What is the primary role of perforin in CTL-mediated cell death?

    <p>Inducing osmotic lysis of target cells</p> Signup and view all the answers

    Which major histocompatibility complex (MHC) is recognized by cytotoxic T lymphocytes (CTLs)?

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

    Natural Killer cells make up 5%–10% of the recirculating lymphocyte population.

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

    NK cells are involved in immune defenses against bacteria and fungi.

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

    NK activity is stimulated by IFN-γ, IFN-β, and IL-12.

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

    Effector CTLs recognize and eliminate altered self-cells, such as heart muscle cells.

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

    What is the primary function of natural killer (NK) cells?

    <p>Recognizing and eliminating altered self-cells, such as virus-infected cells and tumor cells</p> Signup and view all the answers

    What is the role of perforin in NK-mediated killing of target cells?

    <p>Inducing death in target cells by apoptosis</p> Signup and view all the answers

    What cytokines stimulate natural killer (NK) cell activity?

    <p>IFN-γ, IFN-β, and IL-12</p> Signup and view all the answers

    What characterizes the apoptosis caused by natural killer (NK) cell degranulation?

    <p>Release of perforin and granzymes at the junction of interacting cells</p> Signup and view all the answers

    What type of receptors do NK cells employ to deliver inhibition signals?

    <p>Antigen-specific receptors</p> Signup and view all the answers

    What is the primary function of NKp44 and NKp46 found on NK cells?

    <p>Delivering inhibition signals</p> Signup and view all the answers

    What is the opposing-signals model related to NK cells?

    <p>Expression of antigen-specific receptors</p> Signup and view all the answers

    Which proteins are important for cytolysis in CTL-mediated death?

    <p>NKp30, NKp44, and NKp46</p> Signup and view all the answers

    What type of receptors do NK cells employ to deliver inhibition signals?

    <p>C-type-lectin–inhibitory receptors (CLIR)</p> Signup and view all the answers

    What is the primary role of perforin in NK-mediated killing of target cells?

    <p>Inducing apoptosis of target cells</p> Signup and view all the answers

    What is the principal role of cytotoxic T lymphocytes (CTLs)?

    <p>Inducing apoptosis of target cells</p> Signup and view all the answers

    What characterizes the CTL-mediated immune response?

    <p>Recognition and elimination of altered self-cells</p> Signup and view all the answers

    What is the primary function of inhibitory NK cell receptors such as KIR and CD94/NKG2?

    <p>Counteract the activation signal induced by the activation receptor (AR)</p> Signup and view all the answers

    What happens when class I expression is decreased on altered self-cells?

    <p>The activation signal predominates, leading to their destruction</p> Signup and view all the answers

    How are NK cells activated to recognize target cells lacking class I MHC complex molecules?

    <p>By interacting with adhesion molecules and other unknown ligands</p> Signup and view all the answers

    What is the role of expression of class I molecules on normal cells in relation to NK cells?

    <p>It prevents their destruction by effector CD4+ T cells</p> Signup and view all the answers

    In the opposing-signals model, engagement of inhibitory NK cell receptors delivers an inhibitory signal that counteracts the activation signal.

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

    Class I MHC molecules on altered self-cells deliver an inhibitory signal to NK cells.

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

    NK cells can be activated by recognition of target cells lacking class I MHC complex molecules.

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

    Effector cells with direct cytotoxic activity include antigen-specific cytotoxic T lymphocytes (CTLs) and effector CD4+ T cells.

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

    Which cells can mediate Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)?

    <p>Natural Killer (NK) cells, macrophages, and neutrophils</p> Signup and view all the answers

    What is the primary role of perforin in ADCC-mediated killing of target cells?

    <p>Initiating apoptosis signaling</p> Signup and view all the answers

    Which cytokines stimulate Natural Killer (NK) cell activity?

    <p>Interferon-gamma (IFN-gamma)</p> Signup and view all the answers

    What type of cells are directed to specific target cells by binding to the Fc region of antibody in ADCC?

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

    Which type of immune response involves T cells and is responsible for defending against intracellular microbes?

    <p>Cell-mediated immune response</p> Signup and view all the answers

    What is the primary role of CD8 Cytolytic T cells (CLTs) in cell-mediated immunity?

    <p>Killing infected cells with antigens in the cytosol</p> Signup and view all the answers

    In cell-mediated immunity, what is the primary function of perforin?

    <p>Facilitating CTL-mediated cell death</p> Signup and view all the answers

    What is the distinguishing feature of effector cells in the humoral immune response?

    <p>Secreting antibodies</p> Signup and view all the answers

    Effector CD4+ T cells mediate delayed-type hypersensitivity reactions(DTH) in cell-mediated immune responses.

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

    NK cells can be activated by recognition of target cells lacking class I MHC complex molecules.

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

    Effector CTLs mediate immediate-type hypersensitivity reactions (DTH) in cell-mediated immune responses.

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

    Effector cells with direct cytotoxic activity include antigen-specific cytotoxic T lymphocytes (CTLs) and effector CD4+ T cells.

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

    What is the primary function of effector cytotoxic T lymphocytes (CTLs)?

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

    What characterizes the apoptosis caused by natural killer (NK) cell degranulation?

    <p>Apoptosis by osmotic lysis of target cell</p> Signup and view all the answers

    Which cytokines stimulate natural killer (NK) cell activity?

    <p>Interferon-gamma and interleukin-12 (IL-12)</p> Signup and view all the answers

    What is the opposing-signals model related to NK cells?

    <p>Engagement of inhibitory NK cell receptors delivers an inhibitory signal that counteracts the activation signal</p> Signup and view all the answers

    Humoral immunity is the mechanism of defense against intracellular microbes and their toxins.

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

    B cells are activated by protein antigens with signals provided by helper T cells (CD40) and cytokines receptors.

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

    Differentiated B cells eliminate microbes by various mechanisms such as opsonization and phagocytosis or complement activation.

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

    NK cells are involved in immune defenses against bacteria and fungi.

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

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