L7:2 Flashcards
CD4 facilitates binding of HLA class ___ molecules to the TCR
CD8 facilitates binding of HLA class ___ molecules to TCR
HLA Class II
HLA Class I
True or False: CD4/CD8 are mutually exclusive on mature T cells
TRue
In the role of co-receptors, CD4 and CD8 are ___ molecules and function in _____
As co-receptors, CD4/CD8 are adhesion molecules that function in signal transduction
____ is present on all mature T-Lymphocytes and is a critical signaling molecule
CD3
Which molecule is composed of an epsilon, gamma, and delta chain?
CD3
True or False: HLA molecules have a conserved and variable domain
False - T Cell Receptors have conserved and variable domains (Va and Vb)
TCR recognizes ___ and ___ (APC)
TCR recognizes antigen + HLA (APC)
A processed antigen and HLA molecule are recognized and bound by the antigen binding site of the TCR. Which signal does this correspond to?
Signal 1
True or False: Signal 2 leads to leads to activation of T cell, CD3, and zeta tyrosine kinases
False - Signal 1
What part of the TCR forms the terminal antigen binding site?
Variable region domain (Va and Vb)
What are the two functions of CD3?
1) TCR chaperone - transports newly made TCR molecule to cell surface
2) Cellular signaling molecules (transmembrane/cytoplasmic domain)
True or False: CD3 molecules are closely associated with zeta chains
True
True or False: Zeta chains are T-cell specific and located primarily extracellularly
False - zeta chains are NOT T-cell specific and are mostly intracellular
True or False: Zeta chains are involves in transducing intracellular signal from TCR-CD3 complex
True
T cells become activated when the
“immunological synapse” is formed between and ___ (usually a dendritic cell) and a __
cell.
APC ; T Cell
A ___ is a disulfide-linked heterodimer glycoprotein belonging to the Ig
supergene family of molecules
TCR
True or False: All members of the Ig Supergene Family bind and recognize foreign antigens (HLA, Ig, TCR)
True
What type of chains do most TCR’s have?
alpha and beta
True or False: TCR’s are clonally distributed (meaning each T cell bears a unique TCR)
True - allows for antigen specificity
True or False: Positive co-stimulatory interactions are most commonly associated with Signal 1
False - Signal 2
What are the two positive co-stimulatory interactions?
1) B7(CD80): CD28
2) CD40:CD40L
True or False: Co-stimulatory reactions are critical for initial activation of memory T cells
False - Co-stimulatory reactions are critical for initial activation of NAIIVE T cell!!!!
What are the two negative co-stimulatory interactions?
1) PD-L1: PD-1
2) B7:CTLA
_____/_____ strongly inhibits T cells and induces T cell differentiation
PD-L1/PD-1
What co-stimulatory interaction is essential for maintaining peripheral tolerance and limiting immune response?
PD-L1/PD-1
Activation of T-Helper cells is associated with transcription of ______
IL-2
_____: Autocrine growth factor for T-cells
IL-2
What are the two functions of IL-2?
1) Induces proliferation
2) Induces differentiation to effector cell function (production of cytokines) or memory cell
IL-2 Receptor is also known as ___
CD25
True of False: Memory T cells have fewer activation requirements upon second antigen encounter
True
True or False: Memory T cells are less easily activated, compared to native T cells
False - memory T cells are MORE easily activated than naive T cells
Once activated in subsequent encounters with antigen, memory cells become either ___ or ___
effectors or more memory cells
What co-stimulatory interaction is crucial for T cell activation?
B7:CD28
Where does peripheral tolerance occur?
Lymph nodes
True or False: Peripheral Tolerance occurs when T cells are stimulated with secondary stimulation (B7-CD28)
False - Peripheral Tolerance occurs when T cells are stimulated WITHOUT secondary stimulation (B7-CD28)
The absence of this
“second signal” can result in functional inactivation of the T cell called _____
clonal anergy
True or False: Once T cells become anergic they cannot become activated even if they encounter their
specific foreign peptide/MHC molecule
True
repeated stimulation of activated
T cells can cause the T cell to die by apoptosis, also known as ____
clonal deletion
Regulatory T cells can inhibit the activation of T cells by _____
self-peptide/ MHC
