Specific Host Defenses Flashcards
Chapter 17 (122 cards)
1
Q
What is Specificity?
A
Recognizes specific foreign substance
2
Q
What is Non-self regarding cells?
A
Foreign
3
Q
What is self regarding cells?
A
Body’s cells
4
Q
What cells are foreign? (4)
A
- bacteria
- viruses
- pollen
- transplanted tissues
5
Q
How does your immune system obtain memory of specific antigens/infection?
A
After recovering from a specific infection, you are immune to it when exposed again (memory)
6
Q
What are antigens (Ag)?
A
Substance that stimulates an immune response
7
Q
What mediates Specific Acquired Immunity?
A
Lymphocytes
8
Q
What are the two lymphocytes?
A
- T cells
- B cells
9
Q
What type of immunity do T cells provide?
A
Cellular Immunity
10
Q
Where do T Cells Mature?
A
Thymus
11
Q
What type of immunity do B Cells provide?
A
Humoral Immunity
12
Q
Where do B Cells mature?
A
Bone Marrow
13
Q
Where do T Cells originate from?
A
Bone Marrow
14
Q
Where do B Cells originate from?
A
Bone Marrow
15
Q
What do B Cells do?
A
Produce ANTIBODIES that recognize and bind to Ag
16
Q
What do T Cells do?
A
Have cell surface receptor (TCR) that recognizes Ag on surface of TARGET CELL
17
Q
What is acquired immunity?
A
Protection developed over time against a specific Ag after injection/vaccination
18
Q
What are the 4 ways immunity can occur?
A
- naturally
- artificially
- actively
- passively
19
Q
What is Naturally Acquired Active Immunity?
A
Immunity acquired when person encounters the pathogen naturally
20
Q
What is Naturally Acquired Passive Immunity?
A
Natural transfer of preformed Ab from mother to fetus/infant
21
Q
What is Artificially Acquired Active Immunity?
A
Immunity acquired after vaccination against a specific infectious agent
22
Q
What is Artificially Acquired Passive Immunity?
A
Immunity acquired after injection of preformed Ab
23
Q
What is involved in the humoral immune system? (3)
A
- B lymphocytes
- antibody mediated
- effective vs. extracellular
24
Q
What is involved in the cell mediated immune system? (3)
A
- T lymphocytes
- mediated by cell-cell interactions
- effective vs. intracellular
25
What are antigens?
Substance that elicits an immune response
26
Describe antigens (3):
- large
- usually a protein
- can be polysaccharide, nucleoprotein, or glycolipid
27
Which type of antigens are not good? (2)
- lipids
- nucleoacid
28
What different Ag cover the surface of pathogens? (6)
- pili
- cell wall
- capsules
- outer membrane proteins
- flagella
- toxins
29
What is Epitope?
Section on the Ag that Abs bind to
30
What produces antibodies?
B Cells (aka Plasma Cells)
31
Where are antibodies found? (2)
- surface of B cells as Ag receptor
- secreted into serum, lymph, and fluids surrounding tissue
32
What do Ab's produced by ONE plasma cell do?
Recognizes only a single portion of an Ag and binds
33
What are two other names for antibodies?
- Gamma Globulins
- Immunoglobulins
34
What shape do Ab's have?
Y shaped molecule
35
Why is it an Ab's shape beneficial to it?
Flexible Adapter
36
Describe Antibodies (2)
- proteins
- 4 chains
37
Describe the 4 chains of Ab's:
- 2 Identical Heavy Chains (Hc)
- 2 Identical Light Chains (Lc)
38
What holds chains in Antibodies together?
Disulfide bonds
39
What do each Hc and Lc contain?
1 Variable region (V)
40
What does each Lc contain?
1 Constant region
41
What does each Hc contain?
3 or 4 Constant regions
42
What do the variable regions of Hc/Lc make up?
Ag binding site
43
How many antigen binding sites are there on one antibody?
2 (identical)
44
What does Fab stand for?
Fragment antigen binding
45
What do the Ch regions determine?
The Ab (Ig) class
46
What are the five classes of Ig?
- IgG
- IgM
- IgA
- IgD
- IgE
47
Describe IgG (5)
- monomers (individual Y shaped molecules)
- Secondary Immune response
- Can enter tissues + cross placenta
- Activate the Classical Complement Pathway
- Act as an Opsonin
48
What Ig makes up 80% of Antibodies found in serum?
IgG
49
What are IgG's effective against? (3)
- bacteria
- extracellular viruses
- bacterial toxins
50
Describe IgM (5)
- First Ab produced in primary immune response
- M = Macroglobulin (Large)
- 10 binding sites
- Activates Classical Complement Pathway
- Valuable in diagnosing Disease
51
How long is the half- life of IgG?
~23 days
52
Which Ab's half life is ~5-10 days?
IgM
53
What is IgM important for?
Diagnosis of disease
54
What holds IgM monomers together?
J chain
54
What holds 5 IgM monomers together?
J chain
55
Describe IgA (4)
- SECRETORY Abs
- Found in mucous membranes & secretions
- Can be monomer, but mainly DIMER
- first line of defense of specific acquire immune system
56
What Ig makes up 10-15% of Abs?
IgA
57
How long is IgA's half-life?
~6 days
58
How many binding sites does a dimer of IgA have?
4
59
Describe IgD (3)
- found on surface of newly matured B cells
- act as Ag receptor for B cells
- unknown functions
60
What % of Ab's does IgD make up?
0.2%
61
Which Ig has a half-life of ~3 days?
IgD
62
Describe IgE (3)
- found bound to mast cells & basophils
- defense against parasitic worms
- causes allergic response by recognizing allergens
63
What Ig makes up 0.002% of Ab's?
IgE
64
How does IgE bind to cells?
By Fc region to specific cell surface receptors
65
What happens when an Ag binds to a IgE?
Immediate degranulation of mast cells & basophils
66
What happens when IgE causes mast cells & basophils to degranulate? (2)
- cytoplasmic granules' contents (histamine & serotonin) are released
- (histamine) causes increased capillary permeability (vasodilation)
67
Where do B cells in birds mature in?
Bursa of Fabricius
68
Where do B cells in animals mature in?
Bone Marrow
69
What happens in humoral immunity? (4)
- B cells exposed to an extracellular Ag
- B cells mature
- B cells migrate to secondary lymphoid tissue to develop further
- B cells bind with the appropriate Ag
70
When in humoral immunity do B cells selection of Ag receptors occur?
During maturation in bone marrow/bursa of fabricius
71
What do B cells have on their surface? (2)
- IgM
- IgD
72
What are examples of secondary lymphoid tissue? (2)
- lymph nodes
- spleen
73
Where do B cells encounter Ags?
In the secondary lymphoid tissue
74
What occurs when B cells bind with Ags?
Stimulation of proliferation of said B cell (Clonal Selection)
75
What happens during Clonal Selection?
B cells can change into Plasma Cells or Memory Cells
76
Which Cell aids B Cells in Clonal Selection?
Helper T Cells
77
(T/F) All Antibodies produced by one B Cell have different Ag Specificity
False, They all recognize the same epitope
78
What cell rearranges a B Cell's Ig genes during development?
The B Cell itself
79
What happens in Cell Mediated Immunity? (
- T Cells mature in thymus gland
- T Cells migrate to secondary lymphoid tissue
- T Cell encounters Ag and activates
80
What do T Lymphocytes arise from?
A common precursor cell in the bone marrow
81
Where do T Cells mature in?
Thymus Gland
82
What do T Cells mainly fight?
Intracellular Pathogens
83
Where do T Cells encounter the Ag?
Secondary Lymphoid Tissue
84
What do T Cells activate into?
1 of various types of effector T Cells
85
If a T Cell with an Ag specific TCR encounters an Ag...
Proliferation & activation of those Ag Specific T Cells
86
How do T Cells recognize antigenss?
When Antigen Presenting Cells (APC) process antigens and present it to them
87
What are the different types of T Cells? (
- Helper T Cells (CD4+)
- Cytotoxic T Cells (CD8+)
88
What do Helper T Cells do?
Help B Cells & other T Cells to react
89
What nickname do Helper T Cells have?
Commander in Chief
90
What do Cytotoxic T Cells do?
Killer Cells
91
What does CD stand for?
Clusters of Differentiation
92
What activates T Cells?
Ag/MHC complex + Professional APC signal
93
What are examples of Professional APCs? (3)
- Dendritic Cells
- B Cells
- Macrophages
94
How do B Cells & Macrophages become Professional APCs?
Activated by Ag
95
What are the types of MHC Ags? (2)
- Class I
- Class II
96
Describe Class I MHC Ags
All cells (except RBCs, sperm, ovum, cornea)
97
Describe Class II MHC Ags
Activated macrophages, mature B cells, some T Cells
98
What do Class I cells do? (2)
- mark cells as "self"
- directly activates CD8+ cells
99
What do Class II Cells do? (2)
- Recognition of "self"
- required for CD4+ cells to interact with B Cells & Macrophages
100
What do T Cells recognize?
Ag bound to cell surface
101
What holds Antigens onto cell surfaces?
Cell Surface Protein (Marker)
102
What is a Marker
Major Histocompatability Complex (MHC)
103
Describe MHC molecules (2)
- unique to each person
- tell immune system which cells are "self" and "non-self"
104
(T/F) T Cells see antigens that are not within MHC molecules on a cell's surface
False
105
What is another name for Helper T Cells?
CD4+ Cells
106
Describe Helper T Cells (2)
- recognize antigens on macrophages/APCs
- activate macrophages
107
What do activated T Cells do?
Proliferate and secrete cytokines
108
What do activated T Cells do?
Become activated helper T Cells that activate other cells (B, T, macrophages). Some become memory cells.
109
What is another name for Cytotoxic T Cells?
CD8+ Cells
110
What do CD8+ Cells do?
- when activated, they recognize and kill target cells
- produce perforin (lyses cell)
111
What are Cytotoxic T Cells precursors to?
Cytotoxic T Lymphocytes (real killers)
112
How do Cytotoxin T Cells become activated?
By cytokines from Th cells
113
After perforin destroys the cell, what happens?
Granzymes enter and induce apoptosis
114
What do CD8+ T cells recognize?
Antigen presented in association with MHC class I molecules
115
What is a primary immune response?
First encounter with a specific antigen
115
What is a primary immune response?
First encounter with a specific antigen
116
What occurs in primary immune response? (2)
- IgM first to produce, then IgG
- Memory Cells are produced
117
What is a secondary immune response?
Repeat encounter with same antigen (memory)
118
What happens in secondary immune response? (3)
- stimulation of memory cells
- increased levels of IgG & IgM
- Stronger, faster, more specific response
119
What measure the intensity of the antibody mediated immune response?
Antibody titer
120
What does the antibody titer check for?
The amount of antibodies in serum
