Lecture 2 Flashcards
1
Q
Where doe all blood cells develop from?
A
common pluripotent stem cells.
2
Q
What is a primary lymphoid organ?
A
The thymus and bone marrow where starting from the 13th week, some stem cells migrate there.
3
Q
Where do T lymphocytes generate?
A
The thymus where they proliferate, differentiate, and complete their maturation.
4
Q
Where do B cells proliferate, differentiate, and complete their maturation?
A
The bone marrow
5
Q
Where are Ag specific receptors localized?
A
T and B cells
6
Q
The sturucture of these receptors vafies from one cell to another but they are all identicall…
A
on a single cell
7
Q
How long until a naive lymphocyte dies if they do not recognize an Ag?
A
1 to 3 months.
8
Q
Pluripotent stem cells, CD 34 + differentiate into
A
lyphoid progenitor and myeloid progenitor
9
Q
meloid progenitor become what 3 things?
A
mega karyocyte, myeloblast and erythroblast
10
Q
what 2 things do lymphoid progenitors become?
A
t cell precurser and b cell pre cursor
11
Q
CD stands for
A
cluster of differentiation, which indicates a defined subset of cellular surface receptors that identify cell type and stage of differentitation
12
Q
What is refered to as resting lymphoctyes?
A
naive and memory lymphocytes?
13
Q
Why is something a resting lymphocyte?
A
it is not deviding, nor are they performing effector functions
14
Q
Can a person distinguish btw B and T lymphoctes?
A
No, not morphologically.
15
Q
WHen observed on blood smears B and T lymphocytes are refered to as?
A
small lymphocytes (8 to 10 um)
16
Q
What state of rest are naive lymphocytes in?
A
the Go stage of the cell cycle
17
Q
What happens when stimulation occurs?
A
G1 stage of the cell cycle before dividing
18
Q
What are activated lyphoctes called?
A
large lymphoctyes or lymphoblasts 10 to 12 diameter
19
Q
What does the survival of naive lymphocytes depend on?
A
Signals generated by Ag receptors (TCR or BCR) and cytokines
20
Q
What generates survival signals even in the absence of Ag?
A
Ag receptor of naive B cells (BCR)
21
Q
What do naive T lymphocytes (TCR) recognize?
A
Various self Ags weakly, enough to generate surviavl signals but without triggering clonal expansion and differentiation into effecto cells.
22
Q
What is the most important cytokine for survaval of naive T cells? What does it do?
A
interleukin IL-7, which promotes low -level cycling of naive T cells
23
Q
What cytokine is required for B cell survival?
A
The cytokine in the TNF family, B cell-activating factor (BAFF)
24
Q
What doe T cells make contact with and where?
A
epithelial cells, DCs, and Mo in the thymus
25
What provide mechanisms for the slection and differentition of T cells unful to the immune system?
cell-to cell interactions
26
What serve as solube regulatory factors or messengers for the immune system ion general?
cytokines
27
What 4 cytokines play an impotant role in T cell development?
IL-1, IL-2, IL-6, IL-7
28
Where do most naive T cells go after migration from the thymus?
They are maintained in the periphery without proliferating.
29
The number of naive T cells in the periphery remains fairly constat in youn adults,
despite continuouis output from thymus, suggesting balanced loss and replacmeent of peripheral naive T cells
30
What are large numbers of Ag-specifice T cells procuded from?
T cell precursors
31
Each T cell has receptors specific for only one Ag that is gnereated by...
gene rearrangement from multiple, inherited germline genes
32
Why does T cells undergo selection?
to remove those that are highly self reactive
33
What two types of cells are developed in the T cell process?
T helper cells and cytotoxic T lymphocytes (CTLs)
34
What do T helper cells express?
CD4 and provide help for B cell growth and differentiation
35
What do cytotoxic T lymphocytes express?
CD8 and recognize and kill virus- infected cells.
36
Where do mature T cells migrate?
To secondary lymphoid tissues to mediate protection
37
When do B cells start to develop?
Around the 14th week of gestation.
38
WHere does differntiation into B cells occur?
The fetal liver, after birth in the bone marrow, which is the lifetime production.
39
What two different kinds of B cells develop?
B1 and B2
40
WHat is the first antibody express on B cells/
IgM
41
What is expressed after IgM on B cells?
IgD
42
B cells protliferate into ... with T cells help.
memory cells or inot plasma cells
43
What produce and secrete large amounts of Abs?
plasma cells
44
Who do B cells present Ags to?
helper T cells, which is a key step in the cooperation of Th cells with B cells for Ab responses to protein Ags
45
What are generatie lymphoid organs?
bone marrow and thymu
46
What are secondary lymphoid organs?
lymph nodes, spleen, regional lymphoid tissues such as mucosa-associated lymphoid tissue
47
What is peripheral lymphoid organs?
lymph nodes, spleen, mucosal and cutaneous lymphoid tissues
48
What parts of the body do lymphocytes not make it to?
eye, brain, and testicles
49
What specialized venules do the lymphoctes use to get to the lymph nodes, skin, and intestines?
High Endothelium Venules(HEVs)
50
What is not requried for the proliferation of B cells?
IL 2
51
Cells of HEVs are much higher than normal endothelial cells and express much high levels of?
adhesion molecules that serve as homing receptors for lymphocytes
52
What is diapesis?
the passage of blood cells through the intact walls of the capillaries, typically accompanyging inflammation
53
Why do lymphocytes migrate by diapediesis into the tissue/
In response to chemokines
54
How do lymphocytes renter the ciculations/
Efferent lymph vessels that merge into the thoracic duct
55
What are the most important for activation of naive T cells?
Dendritic cells
56
What is maturation of Dcs dependent on?
The cytokine Flt3, which binds to the Flt3 tyrosine kinase receptor on the precursor cells
57
What recognize Ags typically made by microbes and not mammalian cells/
Mo and DCs
58
Where do classical DCs resdie?
in skin, mucosa, and organ parenchyma
59
What responds to viral infections/
plasmacytoid DCs
60
What is important contacts for B cells development?
stromal cells and ctyokines IL1, IL6, and IL7
61
What is not required for the development of B cells, but is needed for the development of T cells?
IL2
62
How does recognition of Ag occur for B cells?
The B cell precursors rearrange multiple, inherited, germline genes that encode B cell receptors
63
What is a terminally differentiated B cell which produces and secretes lg amounts of Abs?
plasma cells
64
B cells present Ags to?
T helper cells
65
What is the function of a plasma cell?
secretion of Abs
66
What do lymphocytes develop from?
bone marrow stem cells and then mature in the genrative lymphoid organ
67
What parts of the body do lymphocytes no reach?
eye, brain, testicles
68
What area does lymphocytes reach via high endothelum venules (HEV)?
LN, skin and intestines, bc they are much higher than normal endothelial cells and their express high levesl of adhesion molecles that serve as homing receptors for lymphocytes
69
How do lymphocytes respond to chemokines??
migrate by diapedis into the tissue
70
How do lymphocytes reenter circulation?
efferent lymph vessels that merge into the thoracic duct
71
Antigens are captured from a site of infections and transported to?
the draining lymph node, where the immune response is initiated
72
Where do fully mature naive T cells and immature B cells migrate ?
into lymphoid organs such as LNs and the spleen
73
Where doe B cells complete there maturation?
LNs and spleen
74
What do naive B and T cells actived by Ags differentiate into?
effector or memory lymphoctes
75
WHere do some effector and memory lymphocytes migrate to?
periperhal tissue sites of infection
76
Abs secreted by effector B cells in LNs, spleen and bone marrow enter?
The blood and are deleivered to sites of infection
77
What are antigen presenting cells???(APCs)
Cells that capture, process, display microbial Ags to lymphocytes and provide signals that stimulate the proliferation and differentation of the lymphocytes
78
What do APC usually refer to ?
A cell that displays Ag to T lyphocytes bc B lymphocytes do not need PAC for their activation
79
What is the major type of APC involved in intitaiting T cell response?
dendrictic cells
80
What are other types of APCs?
macrophages and B cells, both present Ags to T lymphocytes in cell mediated and humoral immune responses
81
What does follicular DC display?
Ags to B lymphocytes during particular phases of humor immune repsonses
82
What provide link btw innate and adaptive immunity?
DCs and Mo
83
What are the most important for the activation of Naive T cells?
dendritic cells
84
What have long membranous projections and phagocytic capabilites?
dendritic cells
85
What linease are DCs from?
myeloid lineage and arise from a precursor that can also differentiate into monocytes
86
What is matturation of DCs dependent on?
cytokine Flt3 ligand, which binds to Flt3 tyrosine kinase receptor on the precursos cells
87
Do activated DCs secrete cytokines?
Yes
88
Fetal hemapoietic stem cells create??
langerhans cells
89
Adult dendritic precursors create?
classical Dcs, plamacytoid Dcs, and inflammatory DCs
90
Where do classical DCs reside?
skin, mucosa, and organ parnechyma
91
Upon activation by microbes, DC migrate to?
LNs where they display microbial protein Ags to T lyphocytes
92
What do plamacytoid DCs respond to?
viral infections
93
What does plamacytoid DCs recognize and produe?
nucleic acids of intracellular viruses and soluble proteins type I interferons, aka IFN-alpha/beta
94
What circulating thing can DCs be derived from?
monocytes
95
Where are FDCs found?
in collection of activated B cells with membranous projections
96
Where do FDCs reside?
LNs, spleen, and mucosal lyphoid tissues
97
What are unrelated to DCs that present Ags to T lymphocytes?
follicular dendirtic cells (FDCs)
98
What do FDCs bind and display? Why?
protein Ags, for recognition by B lymphocytes
99
FDCs have the remakable ability to?
retain complement- fixed Ags on tehirf cell surface for extended periods of time
100
What do FDC immune complexes provide?
antigenic stimulus that drives Ab affinity maturation
101
What are innate lymphoid cells? (ILCs)
several subsets of bone marrow- derived cells w lymphoid morphology
102
ILCs functions?
similar to T cells, but lack T cell antigen receptors
103
What are the 3 major functions of ILCs?
1. provide early defense against infectious pahtogens
2. recognize stressed and damaged host cells and help to elminate these cells
3. influence the nature of the subsequent adaptive immune resposnee
104
What are the first and best characterized innate lyphoid cells?
natural killer cells
105
What doe NK cells sectreet?
IFN-gamma and kill infected and damaged cells
106
What is the HSC nich?
in the bone marrow where there are regions of support for functions of hematopoietic stem cells and other types of hematopoeitic cells (progenitors)
107
What does the HSC nich contribute too?
HSC quience, proliferation, self-renewal and differentiation
108
What does the nich consist of?
A network of vessels, nerve fibers, bone remodeling cells and subpopulations of hematopoietic cells, which reslut in a complex three demential architechture
109
The thymus is made of of??
The cortex and the medulla
110
What is teh Hassal's corpuscle in teh thymus?
part of the medulla whose fuction is poorly understood
111
What makes up the white pulp of the spleen?
the T cell and B cell zones
112
Naive lymphocytes enter the LN through?
an artery, leave the circulation by moving across the wall of high endothelial venule
113
How do B and T cells migrate in the LN?
chemokines that are produced in these areas
114
Where do DC migrate too in the LN?
T cell rich arease
115
activated to be killing microbes
classical activation
116
activated to repair and remodel?
alternative activation
117
What type of receptors to mast cells and baosphils express?
IgE
118
What promote the maturation of eosinophils in myeloid precursors?
GM-CSF, IL-3, IL-5
