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85 Cards in this Set

  • Front
  • Back
T cell receptors able to make any changes after cellular activation:
a. production of secreted receptor
b. isotype switching
c. somatic mutations
d. none, T cells do not undergo changes after cellular activation
d. a, b and c are correct
a. receptor is not secreted and remains on the transmembrane throughout the process
b. no isotype switching
c. does not undergo somatic mutation
D IS CORRECT
e. none of a,b,c are correct
2. T cell receptors fall under allelic exclusion:
a. True
b. False
true - If gene rearrangements are successful, no further
rearrangements occur. This is a process called
allelic exclusion. Alpha and Beta are excluded via allelic exclusion if both gamma ans delta rearrange functionally
Differences and similarities between B and T cells
Why is clonal expansion so important?
a. to select for specific cells
b. to secrete cytokines
c. to kill target cells
d. to increase the numbers of antigen specific cells
d. to increase the numbers of antigen specific cells
as there is no change in affinity of TCR in expansion
The elimination of self-reactive thymocytes is called ________.
a. positive selection
b. negative selection
c. tolerance
d. clonal selection
b. negative selection

positive selection is where thymocytes are selected if they are affinity with MHC, tolerance is not a thing - or otherwise a thymocyte which passes negative selection and clonal selection describes the overall process of VJD rearrangement and negative selection and survival through functional rearrangement and not falling to apoptosis.
5. Which type of T cell is most effective against viruses?

a. Th1
b. Th2
c. cytotoxic T cells
d. regulatory T cells
c. cytotoxic T cells*
6. What portion of the alpha beta T cell receptor determines antigen specificity:

a. V region of alpha and beta chains
b. the constant region
c. CD3
d. the J region
a. V region of alpha and beta chains
7. What are the 2 types of T cell receptors:
CD4+
CD8+
8.what are the 3 kinds of molecules encoded by MHC:
class I, class II, class III
class I, class II, class III
9.what are the 4 regions of the alpha/beta T cell receptor
alpha constant, alpha variable
beta constant, beta variable
10. What are the regions on an human MHC (HLA) Class I locus:
**
alpha 1
alpha 2
alpha 3
tm
c
c
11.What are the regions on an human MHC (HLA)class II locus
12. What are the required signaling molecules for T cell receptors:
**
13.On each T cell what complex are all T cell receptors associated with:
a. CD3
b. CD4
c. CD8
d. RAG1/RAG2
a. CD3
14. What is CD 4 associated with:
a. CD3
b. MHC class II
c. Rag1/Rag2
d. MHC class I
b. MHC class II
15.what is commonly called the invariant chains of T cell receptor complex:
(TCR-α) chain
17.What is the role of the CD3 complex:
a. CD3 necessary for cell surface expression of T cell receptors
b. Forms a corboxyl portion of the secreted TCR
c. transduces signal after antigen interaction with T cell receptors
d. Both a and b are correct
e. Both a and c are correct
**
18.What is the specificity of a T cell receptor:
a. Binds to many different epitopes
b. Is specific for one epitope
c. Binds specifically with one conformational protein antigens
d. none of the above are true.
**
19.What is the structure of the alpha/beta T cell receptor:
**
20.what must a peptide do to induce a T immune response:
**
21.What recognises antigen presented in MHC:
a. Antibodies
b. B cell receptor complex
e. Toll-like receptors
d. T cell receptors
**
22.where are alpha beta T cell receptors found:
**
23.where are gamma delta T cell receptors found:
**
24. ______ is a heterodimer composed of either αand βchains or γand δchains.
a. MHC
b. BCR
c. TCR
d. immunoglobulin
**
25. CD8 and CD4 are classified as ______ based on their abilities to recognize the MHC-Ag
complex and their roles in signal transduction.
a. Co-receptors
b. peptide binding sites
c. immunoglobulins
d. antigens
**
26. How many variable domains does the TCR molecule have and what are they similar
to?
**
27. TCR is associated on membrane with a multi-component signal-transducing complex
called _____.
a. MHC
b. CD3
c. alpha-domain
d. Beta sheet
**
Define antigenic determinant
antigenic determinant:(also, epitope) one of the chemical groups recognized by a single
type of lymphocyte antigen receptor
Define antigen presentation
antigen presentation:binding of processed antigen to the protein-binding cleft of a major
histocompatibility complex molecule
Define antigen processing
antigen processing:internalization and digestion of antigen in an antigen-presenting cel
Define antigen receptor
two-chain receptor by which lymphocytes recognize antigen
Define clone
clone:group of lymphocytes sharing the same antigen receptor
define clonal expansion
clonal expansion:growth of a clone of selected lymphocytes
Define clonal selection
clonal selection:stimulating growth of lymphocytes that have specific receptors
Define constant region domain
constant region domain:part of a lymphocyte antigen receptor that does not vary much
between different receptor types
Define cytotoxic t cells
cytotoxic T cells (Tc):T lymphocytes with the ability to induce apoptosis in target cells
Define effector T cells
effector T cells:immune cells with a direct, adverse effect on a pathogen
Define helper T cells
helper T cells (Th):T cells that secrete cytokines to enhance other immune responses,
involved in activation of both B and T cell lymphocytes
Define immunological memory
immunological memory:ability of the adaptive immune response to mount a stronger and
faster immune response upon re-exposure to a pathogen
MHC d.
major histocompatibility complex (MHC):gene cluster whose proteins present antigens to
T cells
Memory T cells
memory T cells:long-lived immune cell reserved for future exposure to an pathogen
MHC class I
MHC class I:found on most cells of the body, it binds to the CD8 molecule on T cells
MHC class II
MHC class II:found on macrophages, dendritic cells, and B cells, it binds to CD4 molecules on T cells
negative selection
negative selection:selection against thymocytes in the thymus that react with self-antigen
polyclonal response
polyclonal response: response by multiple clones to a complex antigen with many determinants
primary adaptive response
primary adaptive response:immune system’s response to the first exposure to a pathogen
positive selection
positive selection:selection of thymocytes within the thymus that interact with self, but not
non-self, MHC molecules
Regulatory T cells
regulatory T cells (Treg):(also, suppressor T cells) class of CD4 T cells that regulates other
T cell responses
secondary adaptive response
secondary adaptive response:immune response observed upon re-exposure to a pathogen,
which is stronger and faster than a primary respons
T cell tolerance
T cell tolerance:process during T cell differentiation where most T cells that recognize
antigens from one’s own body are destroyed
TH1 cells
Th1 cells:cells that secrete cytokines that enhance the activity of macrophages and other
cells
TH2 cells
Th2 cells:cells that secrete cytokines that induce B cells to differentiate into antibody-secreting plasma cells
Variable region domain
variable region domain:part of a lymphocyte antigen receptor that varies considerably
between different receptor types
Describe the overall structure of a T cell receptor
A TCR has two polypeptides which span the cell membrane which contain like BCRs constant and variable regions. TCRs have disulfide links between the polypeptides and within variable and contant regions. Both peptides form Ag binding site
A TCR has two polypeptides which span the cell membrane which contain like BCRs constant and variable regions. TCRs have disulfide links between the polypeptides and within variable and contant regions. Both peptides form Ag binding site
What are the two classes of T cell receptor?
1. alpha beta
2. gamma delta
1. alpha beta
2. gamma delta
What are the regions of a T cell receptor?
Antigen binding site, alpha chain, beta chain, variable region, constant region, transmembrane region and cytoplasmic tail.
Antigen binding site, alpha chain, beta chain, variable region, constant region, transmembrane region and cytoplasmic tail.
Describe how TCR repertoire is generated
1. VDJ genes
2. N region diversification
1. VDJ genes
2. N region diversification
What is N region diversification
where nucleotides are inserted by the enzyme:
deoxynucleotidyl-transferase.
where nucleotides are inserted by the enzyme:
deoxynucleotidyl-transferase.
Compare VDJ of TCR with BCR VDJ
- TCR more complicated
- alpha and gamma use V and J segments
- beta and delta use VD and J segments
- TCR more complicated
- alpha and gamma use V and J segments
- beta and delta use VD and J segments
Which has the most genes coding for TCR
There are more variable alpha and beta genes than delta and gamma. There are 50-100 alpha/beta and about 5-10 delta/gamma.
There are more variable alpha and beta genes than delta and gamma. There are 50-100 alpha/beta and about 5-10 delta/gamma.
Which genes are located on the same locus? what does this mean?
delta VDJ are located within alphas V and J segments on the same locus. Any productive manipulation of the alpha chain would exclude delta so for this reason, a T cell cannot be both an alpha and a delta.
delta VDJ are located within alphas V and J segments on the same locus. Any productive manipulation of the alpha chain would exclude delta so for this reason, a T cell cannot be both an alpha and a delta.
What coordinates the recombination of TCR?
recombinase activating genes RAG-1 and RAG-2 bind to RSS like in immunoglobulin recombination. RAG-1/2 recognise heptamers and nonamers followed by spacing with the 12/23 rule.
recombinase activating genes RAG-1 and RAG-2 bind to RSS like in immunoglobulin recombination. RAG-1/2 recognise heptamers and nonamers followed by spacing with the 12/23 rule.
What happens if the RAG gene is impaired or missing?
homologous recombination events are abolished, giving rise to severe combined immunodeficiency (SCID).
homologous recombination events are abolished, giving rise to severe combined immunodeficiency (SCID).
Describe components of recombination and their funcitons
nn
What is a functional V region on the alpha chain?
V and J
V and J
Explain the process of creating a TCR
Explain the process of creating a TCR
alpha chain = V + J
- then transcription and splicing with C region generates mRNA that is transplated for alpha protein
beta chain = V + J + D
- tx and splicing with C region generates mRNA that is translated to create beta protein 
- a and b...
alpha chain = V + J
- then transcription and splicing with C region generates mRNA that is transplated for alpha protein
beta chain = V + J + D
- tx and splicing with C region generates mRNA that is translated to create beta protein
- a and b pair after synthesis to yield TCR heterodimer
Define allelic exclusion
two alleles --> m and d
only need one, once one rearranges, the other one doesn't need to and is deleted.
No more rearrangment, the other one won't switch on.
Othe chromosome is not switched on. 2 chances
Describe diversity of TCR
More beta and alpha segments --> different combinations. Total diversity increased than Ab.
What is required to reconise an Ag on TCR
alpha and beta form a pocket and both determine the region for Ag, so connection on both chains.
biggewst diference between BCR and TCR
no somatic hypermutation. Only one rearrangement. No point mutations - no increased affinitiy after Ag contact or during expansion
Generation of TCR diversity
rand
What is the issue with the TCR
receptor will bind but it will not signal 
- CD3 are coreceptor
- needed for signalling
receptor will bind but it will not signal
- CD3 are coreceptor
- needed for signalling
What is ITAM
immunoreceptor tyrosine based activation motif, this is a common mitf seen in the cytoplasmic region
Describe the structure of a CD3 complex
- 4 chains
- Contains 4 chains [(γ, δ, and ε chains) plus ζ (zeta) or η (eta) or θ (theta)] That forms 3 dimers
- combines via electric charge -TCR has a positive transmembrane region, whereas all chains in CD3 complex are negative and thu...
- 4 chains
- Contains 4 chains [(γ, δ, and ε chains) plus ζ (zeta) or η (eta) or θ (theta)] That forms 3 dimers
- combines via electric charge -TCR has a positive transmembrane region, whereas all chains in CD3 complex are negative and thus attracted to it.
What are the chains that can be the fourth chain in the CD3
eta, zeta or theta
eta, zeta or theta
What are examples of accessory molecules on T cells and what do they do? How do they differ from TCR?
- CD2, LFA-1, CD28, CD45R
- Bind APC/target cells (via surface molecules)
- Increase strength of adhesion between APC or target cells
- communicate/transduce signals to interior of T cells
- same on all individuals of the same species
- usefu...
- CD2, LFA-1, CD28, CD45R
- Bind APC/target cells (via surface molecules)
- Increase strength of adhesion between APC or target cells
- communicate/transduce signals to interior of T cells
- same on all individuals of the same species
- useful as cell markers
Describe the stages of T cell and T cell rearrangement
Pro T: TCR gamma
Early thymocyte: Tx of Tcry, rearrangement of Tcrbeta
Thymocyte: Tcr alpha, surface expression, CD4 & CD8
Mature: single positive
T cell: helper/cytotoxic
Pro T: TCR gamma
Early thymocyte: Tx of Tcry, rearrangement of Tcrbeta
Thymocyte: Tcr alpha, surface expression, CD4 & CD8
Mature: single positive
T cell: helper/cytotoxic
How to T cells move through the thymus - what occurs
Cytotoxic T cells
MCH class I 
only respond to MHC
destory infected cells
makes some memory
- memory cells are clones only,  clonal only, sit in tissue - doesn't need random rearragment. years ++
MCH class I
only respond to MHC
destory infected cells
makes some memory
- memory cells are clones only, clonal only, sit in tissue - doesn't need random rearragment. years ++
Describe the helper T cell subsets
Th1
Th2
Th17
Treg
Th1
Th2
Th17
Treg
Which Cd4+ cell regulates helminths
Which CD4+ cell regulates intracellular pathogens?
Th1
Th1
What activates Th1
IL12
IL12
What activates Th2
IL4
IL4
Describe the functions Cd4 cells in adaptive immunity
1. cytokines for macrophages
2. b cell activation and Ab production
3. prime CD8
4. kills cells directly
1. cytokines for macrophages
2. b cell activation and Ab production
3. prime CD8
4. kills cells directly