T cell mediated immunity Flashcards
(113 cards)
1
Q
Which T cell is the direct effector T cell arm?
A
CD8 T cells
2
Q
Which T cell is the regulatory T cell arm?
A
CD4 Th cells
3
Q
Which T cell has a targeted effector function?
A
Both CD8 and CD4 Th
4
Q
Which T cells kill infected or diseased cells?
A
CD8 cells
5
Q
Which T cells enhance innate and apaptive immunity?
A
CD 4 Th cells
6
Q
What initiates T cell immunity?
A
Antigen presentation
7
Q
What is the most common T cell activator?
A
Dendritic Cells
*DCs must be activated
8
Q
Where does antigen presentation occur?
A
In secondary lymphoid organs
9
Q
Dendritic cells mature through ____________
A
Antigen activation
10
Q
Immature dendritic cells in peripheral tissues encounter pathogens and are activated by what?
A
PAMPs
11
Q
In dendritic cell maturation, after being activated by PAMPs, ______ signaling induces ____ and enhances processing of _________
A
- TLR signaling
- CCR7
- Pathogen-derived antigens
12
Q
What role does CCR7 play in dendritic cell maturation?
A
- Directs migration into lymphoid tissues
- Augments expression of co-stimulatory molecules and MHC molecules
13
Q
Mature dendritic cell in ______ primes ______
A
- T-cell Zone
2. Naive T cells
14
Q
Dendritic cells are targeted to lymph nodes by ______ binding _____ and ________
A
- CCR7
- CCL19
- CCL21
15
Q
Dendritic cells take up _____ in the skin and then move to enter a draining ____
A
- Bacterial antigens
2. Lymphatic vessel
16
Q
Dendritic cells bearing antigen enter the draining lymph node, where they settle in the ______
A
T-cell area
17
Q
T/F Antigen presenting cells distribute differentially in lymph nodes
A
True
18
Q
Dendritic cells are primarily associated with what areas?
A
T cell areas
19
Q
Macrophages are primarily associated with what areas?
A
All areas
20
Q
B cells are primarily associated with which areas?
A
B cell areas
21
Q
Dendritic cells present antigen by ____ and ____
A
- MHC I
2. MHC II
22
Q
What is critical for CD8 T cell activation?
A
Cross-presentation
23
Q
Circulating naive T cells are exposed to antigens at ______
A
Lymph nodes
24
Q
T/F Naive T cell population stays the same through lymph nodes
A
False, the naive T cell population rotates through lymph nodes
25
Naive T cells monitor ______ presented by __________
1. Antigens
| 2. Dendritic cells
26
T cells and Dendritic cells form _______
Immune Synapses
27
List the steps of a formation of an immune synapse between a T cell and dendritic cell
1. T cell initially binds dendritic cell through low-affinity LFA-1:ICAM-1 interactions
2. Subsequent binding of T-cell receptors sends signal to LFA-1
3. Conformational change in LFA-1 increases affinity and prolongs cell-cell contact
28
What are the two different regions of the immune synapse formed by T cells and dendritic cells?
1. c-SMAC (inner)
| 2. p-SMAC (outer)
29
How many signals does T cell activation require?
3
30
What are the three kinds of signals that APCs deliver to naive T cells?
1. Activation
2. Survival
3. Differentiation
31
What are the 3 specific things involved with each type of signal received by a naive T cell?
1. Activation: T cell receptor
2. Survival: Co-Stimulatory molecules
3. Differentiation: Cytokines
32
When signaling activation, name 3 things that are associated with the T cell receptor
1. Peptide recognition
2. MHC I or II
3. CD8 or CD4
33
When signaling Survival to a naive T cell, name 4 things associated with Co-stimulatory molecules
1. Survival signal
2. B7 family (APC)
3. CD28 family (T cells)
4. *B7-CD28 required for T cell activation
34
When signaling differentiation to a naive T cell, name 3 things associated with cytokines
1. Paracrine and autocrine signaling
2. Propagation (IL-2)
3. Differentiation
35
IL-2 signals differentiation for which cells?
- CD8
| - All Th
36
IL-4 signals differentiation for which cells?
Th2
37
IL-6 signals differentiation for which cells?
Tfh
38
IL-12 signals differentiation for which cells?
Th1
39
What combination of cytokines signals differentiation for Th17?
TGF-B + IL-16 + IL-23
40
What cytokine signals differentiation for Treg cells?
TGF-B
41
List the different cytokines involved with signaling differentiation
1. IL-2
2. IL-4
3. IL-6
4. IL-12
5. TGF-B + IL-16 + IL-23
6. TGF-B
42
Co-stimulation is required for ______
Activation
43
What happens when you have a specific antigen and co-stimulator?
T cell is activated and proliferates
44
What happens when you have the specific antigen alone?
T cell becomes anergic
45
What happens when an anergic T cell comes in contace with specific antigen and co-stimulator?
T cells stays anergic
46
T/F B7 is only expressed on APCs that have been activated
True
47
Naive T cell TCR activation in the absence of co-stimulation leads to _______
anergy
48
Activation induces what T cell changes?
1. Differentiation
2. Clonal expansion
3. Changes in surface protein expression
4. Migration to target tissues
5. Effector functions
49
CD8 T cells differentiate into what?
- Effector cells
| - Memory cells
50
CD4 T cells differentiate into what?
1. Th1, Th2, Th17, Tfh, Treg
2. Effector cells
3. Memory cells
51
What tissues will T cells migrate to?
- Lymph nodes
| - Sites of infection or damage
52
IL-2 drives _____
Clonal expansion
*for all T cell lineages
53
Resting T cells express only a ______ IL-2 receptor
Moderate affinity
*IL-2R Beta and gamma chains only
54
Activated T cells express a ________ IL-2 receptor and secrete _______
1. High-affinity
2. IL-2
*IL-2 R Alpha, Beta, and Gamma chains
55
Binding of IL-2 to its receptor signals the cell to _______
Enter the cell cycle
56
IL-2 induces ________
T-cell proliferation
57
What type of signaling is prevalent in T cell proliferation and clonal expansion involving IL-2?
Autocrine signaling
58
What inhibits T cell activation and proliferation?
CTLA-4
59
What does CTLA-4 stand for?
Cytotoxic T lymphocyte-associated protein 4
60
T/F CTLA-4 binds B7 with less avidity than does CD28
FALSE, It binds more avidly and delivers inhibitory signals to activated T cells
61
T/F T cells Die after effector functions are performed
False
62
CLTA-4 is expressed on which type of T cells activated or resting?
Activated
63
B7 binds CTLA-4 how much stronger than it will bind CD28?
Twenty fold
64
CTLA-4 binding an APC after activation leads to what?
T cell inhibition
65
You could say that CD8 T cells are selective serial killers T/F
True
66
Do CD8 T cells die once effector functions are complete?
No
67
CD8 T cells only kill cells expressing what?
Targeted peptide via MHC I
68
CD8 T cells differentiate into _____ and _______ cells
1. Effector
| 2. Memory
69
T/F CD8 T cells kill repeatedly
True
70
How many ways are there to activate Naive CD8 T cells?
Two
71
What are the two ways to activating a Naive CD8 T cell?
1. Dendritic cells infected with some types of virus can activate a naive virus-specific T cell on their own
2. Dendritic cells infected with some viruses need help to activate a naive virus-specific CD8 T cell
72
What are the steps for activating naive CD8 cells via dendritic cells that can activate T cell on their own?
1. Dendritic cell sends a sufficiently strong signal to activate the CD8 T cell to effector status
2. Activated Virus-specific CD8 T cell makes IL-2, driving its own proliferation and differentiation
73
What are the steps for activating a naive CD8 T cell by dendritic cells that need help?
1. Dendritic cell activates virus-specific CD4 T cell to secrete Il-2 and virus-specific CD8 T cell to express IL-2 receptors
2. IL-2 from the CD4 T cell drives the proliferation and differentiation of the virus-specific CD8 T cell
74
CD8 T cells kill repeatedly, but also _______
specifically
75
T/F CD8 T cells require a secondary signal to kill
False
76
Protein granules of Cytotoxic T cells contain what 3 things?
1. Perforin
2. Granzymes
3. Granulysis
77
What do perforins do?
Aids in delivering contents of granules into the cytoplasm of target cell
78
What do granzymes do?
They are serine proteases, which activate apoptosis once in the cytoplasm of the target cell
79
What does granulysis do?
Has antimicrobial actions and can induce apoptosis
80
What type of apoptosis can be induced via CD8 T cells?
Caspase-mediated apoptosis
81
CD8 T cells kill through ______ and _______
1. Perforin
| 2. Granzymes
82
CD4 differentiation involves what 3 things?
1. Cytokine Induction
2. Transcription factor
3. Effector cytokines
83
Th1 cells are involved in which type of adaptive immunity?
Cellular
84
Th2 cells are involved in which type of adaptive immunity?
Humoral
85
What induces CD4 T cell subtype differentiation?
Cytokines
86
Differentiation is a response to _______
Pathogen exposure
87
T/F Each T cell has unique effector cytokines
True
88
Cytokines that induce CD4 differentiation come from what two sources?
1. APC itself
| 2. Immediate environment
89
Th1 activate ________
Macrophages
90
What do Activated macrophages do?
1. Express co-signaling ligands
2. Kill intracellular pathogens
3. Release cytokines and antimicrobial effectors
4. Present antigen
91
When pathogens cannot be cleared, what do T cells do?
Form Granulomas
92
Define Granuloma
A compact aggregate of leukocytes that sequester a pathogen
93
T/F Pyogenic granulomas are not true granulomas
True
94
Th1 cytokines enhance Induced innate response T/F
True
95
Th2 cells promote __________
Tissue protection and repair
96
What type of cell responds to prolonged extracellular infection?
Th2
97
What effect do Th2 cells have on Mast cells and eosinophils?
Recruitment and activation
98
T/F Th2 cells release cytokines
True
99
T/F Th2 cells do not activate B cells, that's a Th1 thing
False, they activate a different class than Th1
100
Granulomas are present in a state of ________
Chronic inflammation
101
T/F Both infectious and non-infectious agents are contained within Granulomas
True
102
How many types of granulomas are their?
Several
103
What do Tfh cells do?
Activate B cells and induce class switching
104
What are the preliminary steps of B cell activation by Tfh cells?
1. The Tfh cell recognizes a peptide derived from the B cell's antigen
2. Naive B cell and Tfh cell exchange signals that begin the process of B-cell activation
105
Treg cells _______ other T cells
Suppress
106
T reg cells prevent ___________ in the lymph node
T cell activation
107
Treg cells stop _________ and prevents _______
1. Adaptive immune response
| 2. Autoimmunity
108
What is required in order for a Treg to suppress an autoreactive T cell?
It requires them to interact with the same APC
109
Th17 and Treg cells regulate ________
Mucosal inflammation
110
What cell inhibits mucosal inflammation?
Treg cells
111
Th17 and Treg cells are _______ in the gut
enriched
112
What 3 things do Th17 cells do to regulate mucosal inflammation?
1. Neutrophil recruitment
2. Antimicrobial peptide production
3. Tissue repair
113
Persistent Th17 involvement is present in some autoimmune conditions. Give 4 examples of such conditions
1. Rheumatoid Arthritis
2. Multiple Sclerosis
3. Psoriasis
4. Inflammatory bowl disease
