NK Cells Flashcards
This cell is produced in the bone marrow, found in the peripheral blood system, liver, and spleen, but does not possess receptors produced during gene rearrangement. What cell is this?
NK cell
T/F: Natural Killer cells migrate to tissues in large numbers only when an inflammatory reaction is underway.
True
While of lymphocytic in appearance, they also contain _______, that kill some virus-infected cells.
Granules
What receptors are expressed on NK cells for identification?
CD16, CD56, and a reduction of CD3 receptors
In solely bovine species, what receptor is identified on NK cells?
CD335, or NKp46
What roles do NK cells possess?
The elimination of tumor, virus-infected, and stressed cells
What cytokines are needed for the differentiation of NK cells into LAK cells, or Lymphokine activated killer cells?
IL-2 and IFN gamma
What cell is associated with the production of cytokines and chemokines like IFN gamma, TNF alpha, IL-17, and IL-22, MIP-1 alpha, and MIP-1 beta, which have regulatory roles?
Natural Killer cells
What difference is noted on the cell membrane of a normal cell, versus one that is cancerous, stressed, or virally infected?
The expression of MHC I is not suppressed in normal cells
What roles do the receptors MICA, MICB, Rae-1, and H60, have on cell membranes?
Mark the cell as stressed and for phagocytosis
What broad categories are NK cell receptors placed in?
Activating vs. Inhibitory receptors
Which of the following signals will be blocked? Activating signals blocking inhibitory signals, or inhibitory signals blocking activating signals in normal cells?
Inhibitory signals blocking activating signals, under normal conditions
T/F: An NK cell will only allow a cell to live, if it is recognized as “self” for both the peptide and MHC complex expressed on a cell’s surface.
True
In mice, horses, and rats, the NK cell receptors that recognize MHC I molecules are called -?
KLRs, or Killer cell lectin-like receptors
In humans, cattle, dogs, cats, and pigs, the NK cell receptors that recognize MHC I molecules are called -?
KIRs, or Killer cell immunoglobulin-like receptors
What Natural Killer cell receptor family is associated with CD158?
KIRs, or Killer cell immunoglobulin-like receptors
What are some traits associated with KIRs, or Killer cell immunoglobulin-like receptors?
Polymorphic, transmembranous, and they include LILRs, or leukocyte immunoglobulin-like receptors
Where are KIRs expressed?
NK cells and subsets of lymphocytes
Where are LILRs expressed?
NK cells and several types of leukocytes
What is meant by KIRs and KLRs being mutually exclusive, since they both contain both activating and inhibitory receptors?
That they, KIRs and KLRs, can’t both be found within the same individual, organism, etc.
NKG2D is an example of what type of receptor? What stress proteins does it recognize?
Killer cell lectin-like receptor, which recognizes MICA, MICB, and ULBP in humans; Rae-1, H60, and MULT1 in rats
In ruminants, NKG2D, a KLR receptor, is also expressed on activated -?
Gamma delta T cells
What occurs when there is a large presence of stress proteins on cells, in the presence of NKG2D?
NKG2D will bind to these stress receptors, which will lead to an override of inhibitory signals allowing for NK cell cytotoxicity and elimination of that stressed cell
A reduction in the presence of antigen: MHC I complexes along a cell will mark it for _________ by NK cells.
Elimination
Which of the following is not associated with NK cells?
A) Control of hematopoiesis
B) ADCC against virally-infected cells
C) Activation of macrophages and lysis of stressed cells
D) Bactericidal and fungicidal functions
B) ADCC against virally-infected cells
What three mechanisms are associated with NK cells for elimination of targeted cells?
- Perforin dependent pathway
- CD95/CD95L or Fas/FasL pathway
- ADCC or CD16 pathway
What occurs in the perforin dependent pathway?
Upon recognition and activation, NK cells secrete perforin which form channels into targeted cells for the entry of cytotoxic granules containing granulysin, NK-lysin, and fragmentin (which activate apoptotic zymogens or inactive enzymes) leading to apoptosis
What occurs in the CD95/CD95L or Fas/FasL pathway?
Abnormal cells express the Fas/CD95 receptor, which is recognized and binds to the FasL/CD95L ligand of NK cells, which will then induce apoptosis of the abnormal cell
What occurs in the ADCC or CD16 pathway?
The Fc or CD16 receptor of NK cells recognizes and binds to antibodies that are already bound to antigens, which will then initiate cytotoxicity
What does ADCC stand for?
Antibody-dependent cellular cytotoxicity
T/F: ADCC will only occur if antibodies are present and bound to antigens.
True
What cytokines are needed to activate NK cells?
IL-1, IL-2, IL-12, IL-15, IL-18, IL21, and both Type I and II IFNs
Upon stimulation by NK cell activating cytokines, what will occur to the NK cell?
It will become a lymphokine activated killer cell, or LAK, which has an increased cytotoxic abilities
T/F: FMD in swine will increase the ability to stimulate the conversion of NK cells into LAK cells.
False, FMD and some other viruses have the ability to suppress NK cell cytotoxicity
What cytokine is produced by Natural killer cells, and is associated with the activation of phagocytic leukocytes?
IFN gamma
While thymic in origin, these cells are similar to NK cells and lymphocytes. They are extremely specific, and express an invariant alpha and beta TCR. What cells are these?
Natural killer T cells
A killer cell lectin-like receptor, this receptor is found on NKT cells, which are mostly CD4+ cells that recognize glycolipid antigens on bacterium. What receptor is this?
NK1.1
While unable to develop memory, _____ cells are activated by IL-__, and play a role in allergies, antitumor immunity, autoimmunity, and antimicrobial immunity.
NKT cells
IL-15
Natural killer dendritic cells are associated with the expression of what NK cell and DC receptors, or markers?
Express NK1.1 (on NK cells) and CD11c (DC marker)
What three functions are associated with NK DCs?
The spontaneous lysis of tumor cells, antigen presentation, and the major production of IFN gamma
What is needed for the production of IFN gamma by NK DCs?
CpG or TLR9
Where can NK DCs be located in the body?
Thymus, spleen, liver, and lymph nodes
