58 Questions
What distinguishes Natural Killer (NK) cells from other immune cells like T cells or B cells?
They originate from bone marrow and have a short lifespan.
Which receptors are responsible for cell trafficking in Natural Killer (NK) cells?
Chemokine receptors
How are Natural Killer (NK) cells identified in vitro?
By the lack of CD3 and expression of CD56, CD16.
What is the role of Natural Killer (NK) cells in innate immunity?
They play a role in target cell recognition and killing mechanisms.
How are Natural Killer (NK) cells similar to large granular lymphocytes (LGL)?
They resemble lymphocytes morphologically and contain granules.
Which animals lack an exclusive marker for identifying Natural Killer (NK) cells?
Pigs
What is the role of inhibitory receptors on NK cells?
Recognize MHC-I molecules expressed on normal cells
Which mechanism involves the release of perforin from NK cells?
Perforin-dependent mechanism
What is the function of granzymes and protease in NK cell cytotoxicity?
Induce apoptosis of target cells
Which ligands do activating receptors on NK cells bind to?
Ligands expressed on stressed, infected, or transformed cells
What renders a cell vulnerable to destruction by NK cells?
Reduction or lack of MHC-I expression
Which mechanism involves binding of CD95L on NK cells to CD95 on target cells?
CD95/CD95L (Fas/FasL) mechanism
What is the role of the inhibitory signal in the context of NK cells?
To preserve the target cell
How do NK cells decide whether to kill a target cell?
Based on the expression of stress molecules
What happens when activating signals are blocked by inhibitory signals?
The target cell is preserved
What is the role of the activating signal in the context of NK cells?
To kill the target cells
What is the function of the inhibitory receptors in NK cells?
To transmit the 'do not kill' signal
What happens when the activating receptors sense changes on the target cell surface?
The 'kill' signal is transmitted
Which type of cells express NK1.1 and other KLR family receptors?
Natural killer T cells
Which type of cells are primarily responsible for lysing tumor cells spontaneously?
Natural killer dendritic cells
Which type of cells make up at least 0.5% to 1% of the peripheral blood mononuclear cells?
Natural killer T cells
Which type of cells primarily recognize glycolipid antigens on bacteria?
Natural killer T cells
Which type of cells express CD11c, a DC marker?
Natural killer dendritic cells
Which type of cells are activated by IL-15?
Natural killer T cells
What is the role of CD16 in NK cells?
CD16 is a receptor that allows NK cells to bind to antibodies, leading to cellular cytotoxicity
What are LAK cells?
Lymphokine activated killer cells are NK cells treated with cytokines that have increased cytotoxic capacity
Which of the following is NOT a cytokine that activates NK cells?
IL-3
What is the primary function of NK cells?
NK cells primarily exhibit cytotoxic activity against infected or abnormal cells
What is a characteristic feature of antibody-dependent cellular cytotoxicity (ADCC) by NK cells?
ADCC involves the binding of NK cells to antibodies through CD16
How do NK cells recognize target cells in the CD16 killing pathway?
By recognizing antibodies bound to the infected cell
What is the function of cytokines like IL-2 and IL-18 in regulating NK cell activity?
Activating NK cells
Which type of cells can NK cells be transformed into by treatment with certain cytokines?
Lymphokine activated killer (LAK) cells
In which type of therapy could lymphokine activated killer (LAK) cells be potentially used?
Immunotherapy of tumors
What is a consequence of an enhanced activity of NK cells in certain virus infections?
Enhanced clearance of infected cells
How do NK cells recognize abnormal cells?
By the alteration of cell surface markers on stressed, infected, or transformed cells
What happens when NK cells are activated in vitro with cytokines like IL-2 and IFNγ?
They become Lymphokine Activated Killer (LAK) cells
What is the regulatory role of ME in NK cell cytokine and chemokine production?
Regulating the balance between activating and inhibitory receptors
Which proteins are highly expressed on the surface of stressed cells?
MICA, MICB, Rae-1, H60
What is the function of inhibitory receptors in regulating NK cell activation?
Balancing signals from activating receptors
Which receptors play a crucial role in balancing the activation of NK cells?
Activating and inhibitory receptors
What renders a cell susceptible to destruction by Natural Killer (NK) cells?
Lack of MHC-I expression
Which mechanism involves the release of granulysin, NK-lysin (granzymes), and fragmentin from cytotoxic granules?
Perforin-dependent mechanism
Which cell surface ligand interaction induces apoptosis of the target cell by the CD95/CD95L (Fas/FasL) mechanism?
CD95 on NK cells with CD95 on target cells
What is the primary outcome of perforin channels created by perforin released from NK cells?
Passage of granulysin and granzymes into the target cell
What is the function of activating receptors on NK cells in response to infected, stressed, or transformed cells?
Lysis of abnormal cells
Which molecule released from cytotoxic granules by NK cells specifically triggers the apoptosis of the target cell?
NK-lysin (granzymes)
What is the primary source of Natural Killer (NK) cells in the body?
Bone marrow
Which receptors are not found on Natural Killer (NK) cells?
TCR
Which of the following is not a common location for Natural Killer (NK) cells in the body?
Lungs
Which of the following is a characteristic of Natural Killer (NK) cells in morphology?
Large granular lymphocytes (LGL)
Which of the following is not a distinguishing feature of Natural Killer (NK) cells?
Express CD4
Which of the following animals does not have an exclusive marker for identifying Natural Killer (NK) cells?
Pigs
Which type of cells link the T cell system and NK cells?
NKT cells
Which cells are responsible for producing large amounts of IFNγ upon stimulation through TLR9 (CpG)?
NK DCs
Which type of cells are activated by IL-15 and do not develop into memory cells?
NKT cells
Which type of cells are primarily involved in allergies, antitumor immunity, autoimmunity, and antimicrobial immunity?
NKT cells
Which type of cells express CD11c, a DC marker, and NK1.1, an NK cell marker?
NK DCs
Which type of cells spontaneously lyse tumor cells and can present antigen to naïve T cells?
NK DCs
Explore the origin, role in innate immunity, cell recognition receptors, killing mechanisms, and regulatory functions of Natural Killer (NK) cells in veterinary immunology. Learn about the therapeutic potential of NK cell therapy in humans.
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