Immune and lymphatic system I Flashcards
1
Q
What kind of immunity lacks immune specificity and memory
A
Innate Immunity
2
Q
What is innate immunity’s “response”
A
Inflammation
3
Q
What are the first responders in innate immunity
A
Neutrophils
4
Q
What kind of immunity develops in response to antigens
A
Acquired immunity
5
Q
Is acquired immunity more powerful than innate immunity
A
Yes
6
Q
Does acquired immunity take longer to develop than innate
A
Yes
7
Q
What kind of immunity displays specificity and memory
A
Acquired immunity
8
Q
Temporary immunity due to donated antibodies (i.e., Transplacental passing of maternal antibodies to fetus)
A
Passive immunity
9
Q
Long-lasting/permanent immunity due to self exposure to antigen resulting in memory T cells and B cells specific for antigen
A
Active immunity
10
Q
Antibody-mediated immunity (Plasma cells)
A
Humoral immunity
11
Q
T cells, B cells and antigen-presenting cells
A
Cell-mediated immunity
12
Q
Examples of primary lymphoid organs
A
Thymus and bone marrow
13
Q
Examples of secondary lymph organs
A
Lymph nodes, spleen, tonsils
14
Q
Lymphocytes originate in _____ lymphoid organs and then take up residence in _____ lymphoid organs
A
primary, secondary
15
Q
In primary lymphoid organs precursor cells mature into_______. Each cell is programmed to recognize
A
immunocompetent cells, a specific antigen
16
Q
In secondary lymphoid organs trapped antigens
A
stimulate clonal expansions of mature T and B cells
17
Q
Lymphoid tissue appears in the body as a _____ from ______ lymphoid tissue to _____ lymphoid tissue to ______
A
gradient, diffuse, aggregated, lymphoid organs
18
Q
Are lymph follicles (nodules) enclosed within a capsule
A
No
19
Q
Lymph follicles (nodules) occur _____ or in ______
A
singly or in aggregates
20
Q
Lymph follicles (nodules) are sites of _____ localization and proliferation
A
B cell
21
Q
What are the sites of B cell localization and proliferation
A
Lymph follicles (nodules)
22
Q
Are lymph follicles (nodules) transient
A
yes
23
Q
are spherical, tightly packed accumulations of virgin B cells and dendritic reticular cells that have not been exposed to antigens
A
Primary follicles (nodules)
24
Q
Are derived from primary follicles that have been exposed to non self antigens
A
Secondary Follicles (nodules)
25
Are secondary follicles (nodules) present at birth
No
26
What are the two structural components of a secondary lymph follicle (nodule)
- Corona (cortex)
| - Germinal Center
27
The Corona (cortex) of a secondary lymph follicle has what appearance and composition
- darker peripheral region
| - Composed of densely packed B lymphocytes
28
The Germinal Center of a secondary Lymph Follicle (nodule) has what appearance and composition
- Central, lighter stained region
- Composed of B lymphocytes, memory B cells, plasma cells, dendritic reticular cells which function as antigen-presenting cells
29
Explain the vascular supply of a secondary lymph follicle (nodule)
- Arteriole and venue supply the cortex
- Another arteriole and venue supply the center
- Lymph Capillaries are not present
30
Diffuse lymphoid tissue is made up of
scattered clusters of plasma cells, macrophages, and lymphocytes located in the CT Stroma and various other sites
31
Subcutaneous-associated lymphoid tissue is found in the
papillary layer of the dermis
32
Give 3 examples of Lamina propria- associated lymphoid tissues includes
```
MALT= Mucosal-associated lymphoid tissue
BALT= Bronchial-associated lymphoid tissue
GALT= Gut-associated lymphoid tissue
```
33
Aggregated lymphoid tissue is located
beneath and in contact with the epithelium
34
Examples of aggregated lymphoid tissue
Various tonsils and peer's patches in the ileum
35
3 types of antigen presenting cells
macrophages (monocyte derived)
dendritic cells (monocyte derived)
follicular dendritic cells (lymph node-derived)
36
T cells differentiate into
Helper T cells and Cytolytic T cells
37
What are two kinds of lymphocytes
B and T cells
38
All immune system cells originate in the
bone marrow
39
Immature T cells travel to the
Thymus
40
B-Cells travel to
Specific regions in lymphoid tissue
41
The maturation of B cells involves the appearance of certain cell surface receptors such as
- IgM and IgD
- MHC class II proteins
- Complement receptors
- Ig Fc Receptors
42
What are the 5 classes of antibodies
-IgA, IgD, IgG, IgM, IgE
43
Stem B cells in the bone marrow proliferate and mature in a microenvironmental niche provided by bone marrow stream cells producing _________
Interleukin-7 (IL-7)
44
The antigen receptor complex is composed of
(IgM or IgD) interacting with two additional proteins linked to each other (IgA and IgB)
45
Explain B-cell maturation
Stem B cells in the bone marrow proliferate and mature in a microenvironmental niche provided by bone marrow stream cells producing Interleukin-7 (IL-7)---> This makes a pro B cells into a pre-B cell----> which then express either IgM or IgD along with Iga and IgB thus becoming a immature B cell----> self antigens then test the B cell antigen receptor complex and if it binds to strongly then it undergoes apoptosis and if not then it is enters the circulation as a mature B cell---> enters CT as a plasma cell
46
Antibody structure
- Light and Heavy Chains
- Highly variable regions
- Fab fragment
- Recognizes antigen
- Less variable regions
- Fc Fragment
- Binds antibody to cells
47
IgA is found in
Saliva, milk, GU and respiratory tracts
48
IgD is found on
surface of B cells traveling to lymphoid organs
49
What is the major Ig in blood
IgG
50
What Ig is responsible for most antibody activity
IgG
51
IgE is associated with
Allergic responses
52
What is the first antibody class expressed by developing B cells
IgM
53
What is the function of the Major Histocompatibility Complex
Main function of MHC products is the presentation of antigenic peptides to T cells
54
What are the two classes of MHC gene products
MHC I
| MHC II
55
MHC I is expressed on
the surface of all cells except trophoblast and red blood cells
56
MHC II is expressed on
the surface of B cells and antigen-presenting cells
57
CD8+ T cells recognize
peptide fragments of foreign proteins bound to MHC class I on the surface of cells
58
CD8 is a member of the
Ig superfamily
59
Both the ____ and the ______ are required for the binding of MHC class I protein fragments
CD8, T cell antigen receptor
60
____ recognize peptide fragments of foreign proteins bound to MHC class II proteins on surface of APCs (antigen presenting cells)
CD4+ T cells
61
Pre-T cells develop in
Bone marrow
62
T cells travel to the ____ to complete maturation
Thymus
63
The _____ gene locus expresses gene products responsible for the rejection of grafted tissue between two genetically incompatible hosts
MHC (Major histocompatibility complex)
64
All nucleated cells express class ____ MHC molecules
I
65
Class II MHC molecules are mainly restricted to
antigen-presenting cells (macrophages, dendritic cells, and B cells), thyme epithelial cells of the thymus, and endothelial cells
66
CD4+ T cells recognize antigens
bound to MHC class II molecules
67
What are "double-negative" T-cells
Precursor T-Cells that enter cortex of the thymus from the bone marrow but lack surface molecules typical of a mature T-cell: Thymus Cell receptor (TCR), and CD4 and CD8 coreceptors
68
Where are double negative T-Cells found
in the cortex of the thymus
69
Where are double-positive T-cells found
deep in the cortex of the thymus
70
What are double positive T-Cells
After interacting with Thymic epithelial cells T cells proliferate, differentiate, and express thyme cell receptor (TCR), and the coreceptors CD4 and CD8
71
Where are Single-positive T cells first found
in the medulla of the thymus
72
What happens to Double-positive T cells that cannot recognize self-MHC
fail the positive selection and are discarded (clonal deletion)
73
What happens to Double positive T cells that recognize self-MHC
They mature and express one of the two coreceptor molecules (CD4 or CD8) and become "single-positive" T cells (clonal selection)
74
CD4+ T cells function
Assist CD8+ cells differentiation
| assist B cell differentiation
75
CD8+ recognize antigens bound to
MHC class I molecules
76
Explain how a CD8+ cytolytic T cell kills?
1. ) binds to antigen-presenting cell and is activated by interleukin-1 produced by the antigen-presenting cell (paracrine mechanism), and by interleukin-2, produced by the cytolytic T cell (autocrine mechanism). The cytolytic T cell divides by mitosis to increase the cell population
2. ) In the presence of an antigen-presenting cell containing a pathogen antigen (a virus), cytolytic T cells release protein pore-forming perforin to kill the infected target cell. The CD8+ cytolytic T cell protects itself with protectin, a cell surface molecule that binds perforin. Perforin facilitates the delivery of pro-apoptotic granzyme B proteases to the target cell.
3. ) Fas ligand, released by the cytolytic T cell and bound to the Fas receptor, together with granzyme destroy target cell by apoptosis
77
What do CD8+ T Cells (cytolytic T cells) release
Perforin
| Fas Ligand
78
What is Fas Ligand
Binds to the Fas receptor on a cell and and triggers apoptosis
79
What are the mediators of cellular immunity
CD8+
80
What is the function of Perforin released by CD8+ T cells
Induces cell membrane damage to the target cell
81
CD16+ T cells are better known at
Natural Killer (NK) cells
82
Natural killer cells destroy
tumor cells
83
CD16+ cells are activated by
Tumor cell antigens
| T-helper cells release Cytokines
84
Interleukin-2 effect on NK cells
Stimulates proliferation of NK cells
85
Interferon-gamma effect on NK cells
Activates NK cells
86
Macrophage activating factor (MAF)
Activates Macrophages
87
TNF-beta (tumor necrosis factor)
kills tumor cells directly
88
Activated T cells undergo mitosis: which leads to
- some daughter cells becoming memory cells
| - some daughter cells secrete interleukins
89
T cells attract
B cells
90
B cells have access to what
Free antigens
91
B cells undergo mitosis leading to
- some daughter cells becoming plasma cells
- Secrete appropriate antibodies
- Some daughter cells become memory cells
92
what is an epitope
antigenic property that is noticed by the immune system
93
The complement system is an array of about ___ serum proteins which are synthesized in the ___ and found in the blood
20, liver
94
Classic pathway of complement system
Cascade is activated by antibody binding to pathogen
95
Alternate pathway fo complement system
Cascade is directly activated by the pathogen
96
The complement system facilitates
inflammatory responses
97
The complement cascade (either pathway) involves
coating the pathogen with complement initiating the cascade
98
C1 (the first complement factor in the cascade) is made up of how many subcomponents and what are there names
3, C1q, C1r, C1s
99
Immunoglogulins bind to surface of
pathogen
100
C1q bind to ___ region of Ig
Fc
101
The binding of C1q to Fc region of Ig
activates C1r, which activates C1s, which in turn generates a serine protease that initiates complement cascade
102
Protease C1s cleaves complement protein ____ and ___ into what
Protease C1s cleaves C4 into C4a and C4b
| Protease C1s cleaves C2 into C2a and C2b
103
C2b binds to C4b, which is already bound to the pathogen to make
C4b-2b complex or C3 Convertase
104
C3 convertase cleaves
C3 into C3a and C3b
105
one C3 converts can cleave about ______ C3 molecules
1,000
106
Several C3b molecules bind to C3 convertase to form
C4b-2b-3b complex or C5 convertase
107
protein C5 binds to the C3b component of ______ and is cleaved into
C5 convertase, C5a and C5b
108
once C5 is bound to C5 convertase the
opsonization of the pathogen is complete
109
When C6,C7, and C8 are added to the C4b-2b-3b-5b complex they from
pores in the membrane of the pathogen (lytic pore called the membrane attack complex (MAC))
110
Activation of the membrane attack complex (MAC) on the pathogen leads to
perforations and lysis
111
The complement cascade results in:
- activation of MAC (membrane attack complex) on the pathogen leading to perforations and lysis
- production of opsonins, which are coatings that make the antigens more palatable to phagocytes
- Release of chemotactic agents (chemokines) which attract phagocytes (chemotaxis) to the areas of infection or inflammation
112
What are opsonins
coatings that make the antigens more palatable to phagocytes
113
Parenchyma consists of
the cells that typically pack areas of the lymphoid organ
| - mostly lymphocytes
114
Stroma consists mostly of
reticular fibers and cells, including undifferentiated cells and fixed and free macrophages
115
size of lymph nodes
Varies from 1-25 mm in diameter
116
Lymph node composition
- Capsule
- Trabeculae
- Cortex
- medulla
- Hilus
117
What is the hilus of a lymph node
- Entry and exit point for vessels
- efferent lymphatic vessels as well as arteries and veins enter through the hilus
- Afferent lymphatic vessels enter the convex side of the node
118
Afferent lymphatic vessels pierce the ____ and open into the _____ of a lymph node
capsule, subcapsular sinus
119
______ arise from the sub capsular sinus and penetrate the cortex of the lymph node
paratrabecular sinuses
120
The ______ are confluent with the medullary sinuses at the hilum and penetrate the capsule to join the efferent lymphatic vessel of the lymph node
subcortical sinuses
121
The capsule of the lymph node is composed of
dense collagen fibers, some elastic fibers, and smooth muscle fibers
122
The outer cortex of a lymph node contains
lymph follicles (nodules)
123
Lymph follicles (nodules) of the outer cortex in a lymph node contain
- B cells
- Follicular dendritic cells
- Migrating dendritic cells
124
Secondary lymph follicles (nodules) have
a mantle and Germinal center
125
Primary lymph follicles (nodules) lack
a mantle and germinal center
126
What is the difference between a primary and secondary lymph follicle (nodule)
secondary have a mantle and germinal center
| primary lack a mantle and germinal center
127
The deep (inner) cortex of a lymph node composition
-contains T cells (CD4 helper T cells), macrophages
- high endothelial venules (HEVs)
- which is the port of entry for circulating differentiated lymphocytes to seed lymph node
128
Composition of the medulla of a lymph node
- irregular arrangement of loose medullary sinuses and dense medullary cords
- Sinuses are lined with macrophages
- Cords consist of blood vessels, lymphoblasts, and plasma cells
129
medullary cords of lymph node consist of
blood vessels, lymphoblasts, and plasma cells
130
Medullary sinuses of lymph nodes are lined by
macrophages
131
The medulla of a lymph node is the site of
lymphocyte reentry into lymph stream
132
what is the site of lymphocyte reentry into lymph stream
Medulla of a lymph node
133
The thymus dependent areas of a lymph node are
in the subcortical and deeper medullary regions
134
What is the most important Opsonin
C3b
135
What is the port of entry for circulating differentiated lymphocytes to seed lymph node (note located in the deep inner cortex)
High endothelial venules (HEVs)
