Exam2 Flashcards
(125 cards)
1
Q
Where do T Cells mature?
A
Thymus
2
Q
What are the “antibody-like” receptors found on T Cell surface?
A
T Cell Receptor (TCR)
3
Q
What MHC do killer T cells scan?
A
MHC 1 presented by all cells
4
Q
MHC 2 are scanned by what cells?
A
Helper T cells
5
Q
Helper T Cells secrete what 2 cytokines?
A
IL-2, INF-gamma
6
Q
What are the three antigen presenting cells that helper t cells need for activation?
A
Dendritic cells, Macrophages, B Cells
7
Q
What happens if the TCR recognizes the cognate antigen on MHC but isn’t co-stimulated?
A
The T-Cell is anergized (inactivated)
8
Q
T/F: There are thousands of different TCR’s on a given mature T-Cell
A
False: all TCR on a given T Cell are identical
9
Q
What are the two types of TCR?
A
alpha-beta (traditional and most common)
gamma-delta (non-traditional)
10
Q
Where are T-cells with gamma-delta TCR most common?
A
Intestine, uterus, tongue
11
Q
What is the co-stimulatory molecule found on the T-Cell?
A
CD28
12
Q
What does the CD28 on a T-Cell bind to?
A
B7 molecule on APC
13
Q
What is the group of proteins needed for signaling?
A
CD3 Proteins
14
Q
T/F: CD8 is the co receptor found on killer T-cells
A
True
15
Q
What is the function of cholesterol lipid rafts?
A
Contain large # of signaling molecules, making signaling process easier
16
Q
T/F: Naïve T-cells have more lipid rafts
A
False: more experience=more rafts
17
Q
How many dendritic cells does one helper t-cell scan per hour?
A
1000 dendritic cells
18
Q
What does the CD40L and CD40 binding lead to?
A
Lengthens the life of the dendritic cell involved
19
Q
How long does the complete activation of a helper T-cell take?
A
4-10 hours
20
Q
What receptor is absent from naïve T-cell surface?
A
IL-2
21
Q
What are the two jobs of T-helper cell?
A
1) Stay in blood/lymph to help B-Cells and Killer T Cells
2) Enter battle sites to help reactivate other cells there
22
Q
What do T-helpers secrete as a form of help?
A
Cytokines
23
Q
What are the three major types of T-helper cells?
A
Th1, Th2, Th17
24
Q
TLR4 recognizes which 2 pathogens?
A
Gram-negative bacteria, viruses
25
TLR3 recognizes what?
double stranded RNA
26
Gram-positive bacteria are recognized by what toll-like-receptor?
TLR2
27
Th1 Helper T Cells are needed in what kind of attack?
Th1=viral or bacterial attack
28
T/F: Th2 Helper T Cells are needed in parasitic attacks
True: Th2=parasitic/food-borne bacteria
29
What are the classical cytokines put off by Th1?
TNF, INF-gamma, IL2
30
What cytokines are put off in a parasitic attack?
IL-4, IL-5, IL-13
31
What is the goal of Th1 Cells?
Activate infected macrophages (INF-gamma) and NK cells (IL-2)
32
T/F: IL-5 causes B-cells to make IgG?
False: IL-5--> IgA
33
What does IL-13 stimulate?
mucus in the intestine to protect from food-born bacteria
34
T/F: IL-4 stimulates B-cells to make IgG?
False: IL-4 --> IgE
35
Th17 Helper T Cells are needed under what kind of attack?
Th17=Fungal attacks
36
What is dendritic cells response following Th17 Helper T Cell stimulation?
Dendritic Cells make TGF-beta and IL-6
37
What are the two interleukins associated with Th17 helper T cells stimulation?
IL-17 and IL-21
38
What are Th0 Helper T Cells?
Unbiased cells that move to the battle site where they'll commit to one of the 3 major types (Th1, Th2, Th17)
39
What signals is needed for Th0 to commit to Th1? Th2? Th17?
IL-12-->Th1
IL-4-->Th2
IL-6 & TGF-beta-->Th17
40
T/F: CTL's only need an activated dendritic cell to be activated
True
41
What interleukin put off by T-helper cells is needed for CTL proliferation?
IL-2
42
T/F: The Fas Ligand is found on the CTL and the Fas protein is found on the infected cell
True
43
What are the 2 enzymes CTL's use to kill infected cells?
Perforin to poke holes in bad guy, and Granzyme B to initiate apoptosis
44
What disposes of the remnants leftover from apoptotic cells?
Macrophages
45
T/F: T Cells can only look at protein fragment antigens
True
46
What are the 2 primary lymphoid organs?
Bone Marrow and Thymus
47
What are the 3 secondary lymphoid organs?
Lymph nodes, Spleen, Mucosal Associated Lymphoid Tissue (MALT)
48
Specifically, where are follicular dendritic cells (FDC) found?
Primary Lymphoid Follicle of Secondary Lymphoid Organ
49
What is the purpose of follicular dendritic cells?
Catch and opsonize antigen for B Cells to see
50
T/F: FDC are exclusive to secondary lymphoid organs
False
51
T/F: FDC's make clustering of B-Cell Receptors more likely
True
52
What is a germinal center?
A mass of proliferating B Cells that create a darker zone and produce swelling in the lymph nodes
53
In individuals deficient in T Cells, B Cells can only make which type of antibodies?
IgM
54
In a lymph node, where are B Cells found? T Cells? Macrophages?
B Cells-->cortex
T Cells-->paracortex
Macrophages-->subcapsular sinus
55
How may a lymphocyte enter a lymph node?
An arteriole or incoming lymph
56
What is unique about high endothelial venules?
Columnar cells that offer room for the passage of cells in and out
57
How long does it take the spleen to filter all the blood in your body?
30 min
58
How may a lymphocyte enter the spleen?
Blood only, no lymph traffic
59
Where do efferent lymphatic vessels from the spleen drain into?
pancreaticosplenic lymph nodes
60
In the spleen, where are T Cells found? B Cells? Macrophages? Resident Dendritic Cells (RDC)?
T Cells=periarteriolar lymphocyte sheath (PALS)
B Cells=area between PALS and marginal sinuses
Macrophages and RDC=marginal sinuses
61
What is the purpose of the red pulp in the spleen?
removes old RBC's and recycles iron
62
T/F: Macrophages mediate inflammatory response via release INF-gamma
False: macrophages release TNF
63
What are M Cells?
"bouncers of Peyer's Patches" encloses selective antigens in vesicles (view microbiota as self)
64
What types of T helper cells are found in Peyer's Patches?
Th2 cells that stimulate B Cells to make IgA
65
What cytokines are put off by activated Thelper cells?
TNF, INF-gamma, IL-2
66
What cytokines are put off by activated T reg cells?
IL-10, TGF-beta
67
What is the function of T-regs TGF-beta cytokine?
reduce proliferation and reduce CTL killing
68
T/F: IL-10 reduces proliferation and blocks co-stimulatory signals
True
69
Under battle conditions, epithelial cells of the intestine produce ___, and dendritic cells produce ___.
Epith=TGF-beta
| DC=IL-6
70
What two cytokines are needed for Th0 to commit to being Th17?
TGF-beta, IL-6
71
Regarding co-stimulation, virgin T-cells express ___ and experienced T-cells express __, both of which bind B7.
Virgin=CD28
| Experienced=CTLA-4
72
T/F: B7 more likely to bind CTLA-4
True: prevents experienced T cells from constantly being re-stimulated
73
What is the result when CD28 binds with B7?
Amplifies signal and lowers # of TCR crosslinks needed for activation
74
Which of the following lives the longest: Macrophages, Neutrophils, Dendritic Cells?
Macrophages
75
T/F: Once T-cell is activated, this binding extends lifetime
False: once activated, longevity reduced
76
What is AICD and who is most vulnerable to it?
Activation-Induced Cell Death, experienced T-cells Fas proteins more and more sensitive to ligation with continual reactivation
77
What occurs when the Fas ligand on the NK cell/CTL binds with the Fas protein?
induces apoptosis
78
What is the major Ab class found in the intestines?
IgA found in mucosa
79
What is an inducible regulatory T cell (iTreg)?
CD4+ cell that produces cytokines that restrain immune system
80
What are the 2 subtypes of iTreg?
Tr1 and Th3
81
What are nTregs and where do they develop?
Develop in thymus, protect against T-cells that would recognizes self and lead to autoimmune dz
82
T/F: When NK cells die off, INF-gamma levels decrease, allowing macrophages to go into resting state
True
83
Which Ab has the longest lifespan?
IgG
84
What is the name of the zinc-dependent hormone produced by the thymus?
Thymulin
85
T/F: Central tolerance induction occurs in the thymus
True
86
T/F: Cells enter thymus from blood via high endothelial venules (HEV)
False, no HEV present in thymus
87
What do nude T-cells express in high amounts that protects it from apoptosis?
Bcl-2
88
T/F: Double-positive (DP) cells in thymus have both CD4 and CD8 receptors, little Fas protein, and little Bcl-2.
False: DP cells have both CD4 and CD8, A LOT of Fas protein and little Bcl-2.
89
What has very little Fas protein, and a lot of Bcl-2?
Nude T-cells
90
What is the most common lymphocyte in the thymus?
Double Positive (DP) cells
91
What 2 tests must DP cells pass to survive?
MHC Restriction
| Tolerance to Self
92
MHC Restriction is a ___ selection test, whereas Tolerance to Self is a ___ selection test.
positive (cells answer should be yes), negative (cells answer should be no)
93
Where does the positive selection test occur?
MHC restriction occurs in the cortex of the thymus
94
What is the MHC Restriction test?
Determining whether T-cells recognize self MHC molecules (they should, if not-->apoptosis)
95
What types of MHC's are presented in the cortical epithelial cells of the thymus?
Both MHC1 and MHC2
96
When do DP cells commit to becoming either CD4 or CD8 cells?
After MHC Restriction test but before Tolerance for Self test
97
Which 2 cells give the Tolerance for Self test?
Thymic Dendritic Cells and Medullary Thymus Epithelial Cells
98
What is the thymic dendritic cells purpose?
Check whether single-positive T-cells recognize self peptides as foreign, if they do recognize-->apoptosis
99
Why do thymic dendritic cells have such a short lifespan?
Constantly having an updated 'self' peptide so single-positive T-cells get up-to-date training
100
What is the medullary thymic epithelial cell's purpose?
Test single-positive T-cells for tissue-specific proteins to ensure they don't recognize these proteins as foreign and cause autoimmune dz
101
How do medullary thymic epithelial cells get these tissue-specific proteins?
Utilize autophagy to engulf and present these proteins on MHC2 molecule for Tolerance of Self testing
102
What is the pass rate for both MHC Restriction and Tolerance for Self tests?
1/30, the rest are apoptized and eaten by macrophages
103
How long does the testing process for DP cells take?
2 wks
104
Positive selection results from a ___interaction between TCR and MHC whereas Negative selection results from a ___ interaction.
+=weak
| -=strong
105
What protection is offered if a T-cell that may bind with a rare self antigen gets thru the 2 tests?
Limited circulation thru secondary lymph organs limits likelihood of T-cell encountering rare self antigen.
106
People who lack ___protein expressed on nTregs tend to die young of autoimmune dz.
Foxp3 protein
107
What protection is provided if a naïve T cell strays into tissues where it could potentially bind to a rare self Ag?
Peripheral Tolerance; this naïve cell lacks co-stimulatory molecules-->it's anergization (neutering)
108
What is the final layer of protection if there's a self-binding T-cell that escapes and starts going nuts in your tissues?
Activation-Induced Cell Death (AICD) if it keeps binding it becomes more sensitive to the Fas ligand-protein binding that would lead to cell death
109
Where does B-Cell tolerance occur?
Bone marrow
110
T/F: B Cells that recognize self are sentenced to apoptosis
False: have the chance to change via "receptor editing"
111
What % of B-cells can "receptor edit"?
25%
112
What is another term for "receptor editing"?
Somatic Hypermutation
113
What is the source for testing B-Cells for Tolerance of Self?
Follicular Dendritic Cells (FDC)
114
When a B-cell is activated what three types of cells are made?
Short-lived Plasma Cells, Long-lived Plasma Cells, Central Memory B Cells
115
Where are both types of plasma cells made?
Lymphoid follicles of secondary lymphoid organs
116
What are the 3 differences between short lived and long lived plasma cells?
1. Short lived travels to bone marrow and spleen (LL only to bone marrow
2. Short lived=Ab factories, LL only modest amts of Ab
3. LL provide life-long Ab protection (SL die after a few days)
117
T/F: Memory stem cells proliferate slowly and replace long-lived plasma cells that die from old age
True
118
If we encounter the invader again, central memory cells do what?
proliferate and make more short-lived plasma B cells
119
Upon activation, what 3 cells do T cells make?
Effector T Cells, Memory Effector T Cells, Central Memory T Cells
120
Which T cell type travels to the battle sit to fight and dies a few days later?
Effector T Cells
121
___travel to battle site and can stay there for years whereas ___ stay in the 2ndary lymphoid organs and bone marrow.
Memory Effector Tcells, Central Memory T Cells
122
Which T Cell type goes dormant?
Memory Effector T Cells
123
T/F: Only T helper cells can make memory cells
False T helpers and T killers can make memory cells via same process
124
T/F: innate memory is static
True, it doesn't update
125
T/F: If 2 people encounter the same Ag, they will develop the same adaptive memory
False, no two humans have the exact same adaptive memory
