NK cells and Friends Flashcards
Which lymphocyte cell destroys diseased self cells, is innate as well as adaptive, is similar to T cells, interacts with MHC I and recognizes its absents, balances activation and inhibitory signals and may form memory cells?
Natural Killer Cells
What are two major activating NK-cell receptors?
1-NKG2D: lectin-like, MIC-A/B and ULBP1-6 ligands
2-CD16: IgG like, IgG ligand
What is the lectin-like inhibitory NK-cell receptor that binds HLA-E with bound peptides derived from HLA-A,B,C?
NKG2A
What are 4 Ig-like inhibitory NK-cell receptors?
1-KIR2DL1: C2 epitope of HLA-C
2-KIR2DL2/3: C1 epitope of HLA-C
3-KIR3DL1: Bw4 epitope of HLA-A,B
4-KIR3DL2: HLA-A
Which three MHC class I subtypes are bound by T cell and NK cell receptors?
HLA-A,B,C
Which 2 MHC class I subtypes are bound by NK cell receptors only?
HLA-E,G
Which MHC class I subtype is bound by intracellular chaperones?
HLA-F
NKG2A NK cell receptor predominantly binds what?
HLA-E
KIR receptors predominantly bind what?
HLA-A,B,C
What are the three major NK cell receptor families?
1-CD16 (Low affinity IgG Fc receptor
2-NKG family
a.NKG2A (inhibitory receptor binding HLA-E)
b.NKG2D (Activating receptor binds MIC proteins)
3-Killer-cell immunoglobulin like receptor family (KIR) Bind HLA-A,B,C and inhibit NK cell activation
Which activating mechanism of NK cells requires two or more signals, MHC surveillance and responds to Stress ligands?
Innate
Which activating mechanism of NK cells requires only one signal and targets IgG through Fc receptor?
Adaptive
NK cell interaction of HLA-E with NKG2A does what?
Prevents NK cell from attacking a healthy cell
A cell that lacks HLA-E and expresses MIC engages NKG2D in combination with 2B4 and does what?
Activates NK cell to kill the infected cell
What are the three cell states that regulate NK cell targeting?
1-Protection-Healthy cells express both stimulating and inhibitory signals
2-Missing-self- unhealthy cells reduce MHC I expression
3-Induced self- Unhealthy cells increase stress ligand expression
What process occurs in the bone marrow, primes NK cells for activation with activating and inhibiting balance?
Education
Interaction of KIR2DL3 and C1 during NK cell development educates the cell to do what?
Be sensitive to loss of C1 expression. Lack of C1 expression leads to NK killing of cell
An Immature NK cell in bone marrow expresses inhibitory KIR that recognizes self HLA-C to do what?
Educate the NK cell to recognize the inhibitory receptor to not kill when present
What are 3 NK cell activation responses?
1-Target cell interaction
2-Leukocyte interaction (antigen presenting cells, Th cells, NKT cells)
3-Cytokines
What are 2 NK cell effector functions?
1-Cytokine release
2-Cytotoxicity
What are the three NK cell cytotoxic effector responses?
1-Degranulation
2-Death-receptors (induced Apoptosis)
3-Interferon and Nitric oxide
What do γ:δ cells do?
Monitor tissue health
What three types of antigens do γ:δ cells bind?
1-Phosphoantigens
2-Phospholipids
3-Lipids
What do CD1 molecules bind?
Lipid antigens
The exquisite specificity of the interaction with hydrophilic head groups of self and non-self lipids are detected by presentation to γ:δT cells by what?
CD1d
What are 3 γ:δ T cell effector functions?
1-Cytotoxicity
2-Immune regulation (adaptive and innate, cytokine release)
3-Tissue repair and homeostasis
Which cells express invariant α/β T cell receptors, recognize CD1d, act as helper and cytotoxic cells, require both activated TCR and NK cell receptors to be active and are found within tissue?
NKT cells
*do not form memory cells
Activated NKT cells perform what three helper and cytotoxic functions?
1-Lipid antigen detection
2-Cognate interactions (NK cells, B cells, Macrophages, Neutrophils)
3-Fas ligand-mediated cytotoxicity
