Section 2 Flashcards
1
Q
What kind of immunity is specific?
A
Adaptive
2
Q
What kind of immunity has memory?
A
Adaptive
3
Q
What are the 2 types of adaptive immunity?
A
1) Antibody-mediated
2) Cell-mediated
4
Q
Define antigen
A
Any molecule that reacts specifically with an antibody or antigen receptor on a lymphocyte
5
Q
Does an antigen induce an immune response?
A
Not necessarily
6
Q
Define immunogen
A
An antigen that can induce an immune response
7
Q
Define antigenic
A
The relative ability of an antigen to elicit an immune response
8
Q
What is another word for antigenic?
A
Immunogenic
9
Q
Define epitopes
A
Discreet regions of an antigen that are specifically recognized by adaptive immune system
10
Q
What is the main immune cell of the body?
A
Antibody
11
Q
What produces antibodies?
A
B cells
12
Q
Where do B cells develop?
A
Bone marrow
13
Q
What do antibodies neutralize?
A
Free-floating particles such as bacteria, toxins, and free viruses
14
Q
What do B cells do in response to extracellular antigens?
A
Proliferate and differentiate into Y-shaped proteins called antibodies
15
Q
What does a B cell become if it doesn’t become an antibody?
A
A memory cell
16
Q
What is special about memory cells?
A
They respond faster when exposed to the same antigen again
17
Q
What is activated when an antibody binds to an antigen?
A
C1
18
Q
What does C1 get converted to in the classical complement pathway?
A
C1qrs
19
Q
What does C1qrs do, and does it do this fast or slow?
A
Splits C4 and C2 very fast
20
Q
What is formed from the splitting of C4 and C2?
A
C4b2a
21
Q
What is another name for C4b2a?
A
C3 convertase
22
Q
What does C3 convertase do in the classical complement pathway?
A
Splits C3 into C3a and C3b
23
Q
What does C3b do in the classical complement pathway?
A
Binds to microbe-antibody complex and remaining components (C5b, C6, C7, C8, and C9) to form MAC attack
24
Q
A defect in ____ will mean no complement system at all
A
C3
25
What are the 2 functional regions of an antibody?
Arms and stem
26
How many arms does an antibody have?
2
27
How many stems does an antibody have?
1
28
What do the arms of an antibody do?
Bind to specific antigen
29
What does the stem of an antibody do?
Tags antigen for destruction
30
How many types of light chains are there and what are they based on?
2 types based on amino acid sequence of the constant regions
31
What are the 2 types of light chains?
Gamma and K
32
Are the light chains identical or different?
Identical
33
How many types of heavy chains are there and what are they based on?
5 types based on amino acid sequence of the constant region
34
What are the 5 types of heavy chains and what antibody type does each correspond with?
- micro = IgM
- gamma = IgG
- alpha = IgA
- delta = IgD
- epsilon = IgE
35
What is the most abundant immunoglobin?
IgG
36
What kind of structure does IgG have?
Monomeric
37
How many subclasses of IgG are there and what are they based on?
4 subclasses based on amino acid sequence of the C regions of heavy chains
38
Define opsonization
Enhances phagocytosis by acting as a flag for phagocytes when Fab is bound to antigen and Fc is exposed
39
What are the functions of IgG?
- Opsonization
- Neutralize viruses & toxins
- Secondary response
- Crosses placenta
40
When is IgM monomeric?
When attached to B cell surface as receptor
41
When is IgM pentameric?
In serum
42
What does pentameric mean?
5 monomers held together by J chain
43
What are the functions of IgM?
- First antibody produced during primary response
- Activates part of innate defences
- Agglutinates particular antigens
44
What happens to IgM levels once IgG levels increase?
IgM levels decrease
45
What is the structure of IgD?
Monomeric
46
What type of chain does IgD contain?
Delta
47
Where is IgD found?
In serum and on B cell surface as a receptor
48
What is the function of IgD?
Unknown
49
What is the primary antibody produced by cells of the mucous membranes?
IgA
50
Where is IgA found?
In mucosal secretions
51
Where is IgA found as a monomer?
In serum
52
Where is IgA found as a dimer and why?
In solution to resist proteins
53
What are the functions of IgA?
- Prevent bacteria and viruses from attaching to mucous membranes
- Passive immunity
54
What is the structure of IgE?
Monomer
55
What is the function of IgE?
Cause allergy symptoms
56
Where do T cells mature?
Thymus
57
Do T cells recognize free antigen?
No, antigen must be presented to it by one of body's own cells
58
What do T cells bind to?
Peptide derived from intracellular organisms complexed with MHC
59
What does the T-cell receptor bind to?
Complex of MHC molecule and peptide
60
What class of MHC cells do Th1 cells bind to?
Class 2
61
What happens when Th1 cells bind to class 2 MHC cells?
T-cell releases macrophage activating factors (IFNgamma)
62
What are the 2 major functional types of T cells?
1) Cytotoxic T cells
| 2) Helper T cells
63
What do Tc cells do?
Destroy infected or cancerous cells
64
Tc cells have CD_
8
65
Th cells have CD_
4
66
What class of MHC cells do Tc cells associate with?
Class 1
67
What do Th1 cells do?
Activate macrophages
68
What do Th2 cells do?
Activate B cells
69
What is the best way to identify a cell on the antigen present on its surface?
With antibodies
70
What do T lymphocytes do once they are activated?
Help macrophages kill parasites
71
What is the role of T lymphocytes after a macrophage engulfs a parasite?
T lymphocytes need to give the macrophage another signal for the macrophage to kill what it engulfed
72
What do T lymphocytes inhibit and how?
- Intracellular replication of viruses
| - Tc cells recognize class 1 MHC on viral infected cells
73
Describe the process of antibody-dependent cellular toxicity
- Effector cells bind through their surface receptors to antibodies, coating the target cells
- Effector cells become activated and release material damaging targets (macrophages, eosinophils, NK cells)
74
What is the lymphoid system?
A collection of tissues and organs designed to bring B and T cells into contact with foreign antigens
75
Are lymphocytes highly or moderately specific?
Highly
76
What is the function of lymphatic vessels?
Carry lymph collected from fluid that bathes body tissues
77
Where are lymphatic vessels found & why?
All around body so lymphocytes don't have to go far to find antigens
78
What are the primary lymphoid organs?
Bone marrow and thymus
79
What is the precursor of B and T cells?
Hematopoietic stem cells
80
Where do T cells originate?
Bone marrow
81
What occurs once lymphocytes are mature?
Gather in secondary lymphoid organs waiting to encounter antigen
82
What are examples of secondary lymphoid organs?
Lymph nodes, spleen, tonsils, adenoids, and appendix
83
What occurs after lymphocytes make contact with an antigen?
Proliferate, forming clones of cells specific for that antigen
84
What is the function of mucosal-associated lymphoid tissue (MALT)?
Prevents microbes from invading mucosal surface
85
What is the function of skin-associated lymphoid tissue (SALT)?
Prevents microbes from invading skin
86
What do B cells have on their surface?
Immunoglobulin
87
What do T cells have on their surface?
T-cell receptors
88
Describe clonal selection
Only B cells capable of making the correct antibody will bind to antigen
89
What drives clonal selection and why?
Antigen so the body isn't wasting energy
90
Define clonal expansion
Cells that bind antigen begin dividing and produce a population of clones
91
What occur after clonal expansion before activation can occur?
Th cells give lymphocytes another signal to activate; this is to prevent immune system from mounting a response against self
92
Do T cells fine-tune themselves upon binding with an antigen?
No
93
Do B cells fine-tune themselves upon binding with an antigen?
Yes with somatic mutations
94
What is the basis for the principle of vaccination?
Memory cells
95
What is a toxoid?
A toxin without the portion that can kill a human
96
How do antigens stimulate B cells?
With the assistance of Th cells
97
What occurs when Th binds to an antigen on a B-cell surface?
Cytokine production occurs to activate B cell, which undergoes clonal expansion
98
What are cytokines?
Soluble intercellular communication factors (hormones of immune system)
99
Are cytokines antigen specific?
No
100
What is the main function of cytokines?
Control of infection and development of pathology
101
What is an interferon?
A molecule secreted by virus-infected cells that interferes with viral replication in bystander cells
102
What is important about cytokines that are produced by subsets of lymphocytes?
They can suppress the activity of T cells
103
What affect does IL-4 have on Th1 cells?
Downregulates them
104
What affect does IFNgamma have on Th2 cells?
Suppresses their activity
105
What stimulates the immune system?
Antigens
106
What does IgM have a positive feedback on?
Formation of antibodies
107
What does IgG have a negative feedback on?
Stimulation of B cells
108
What happens to antigens and antibodies once the number of IgG cells increases?
Antigen becomes neutralized, so antibodies are no longer needed and they become suppressed
109
Which immunoglobin is most likely to bind to macrophages and polymorphs?
IgG
110
Which immunoglobin protects external surfaces?
IgA
111
Which immunoglobin initiates inflammation?
IgE
112
Which immunoglobin fixes to homologous mast cells and basophils?
IgE
113
What is another way that the acute inflammatory response can be initiated without an antibody and an antigen binding?
When an antibody binds to a mast cell
114
What happens if there is more than one antibody in the antigen-antibody complex?
Antigen-antibody complex will activate phagocytic cells
115
How do antibodies block microbial interactions?
By binding with either the receptor or toxin/virus
116
Which MHC class of molecules is more prevalent?
MHC class 1
117
Where are MHC class 2 molecules found?
Mainly on macrophages and B cells
118
What occurs when a TH1 cell and a class 2 MHC molecule combine?
The T cell is triggered to release macrophage activating factors
119
What happens if a microbe makes it past the IgA-coated mucosal surface?
The microbe will encounter a mast cell bound to IgE, causing the release of mediators of the acute inflammatory response
120
What are lymphocytes derived from?
Stem cells differentiating in primary lymphoid organs
121
What does MALT produce?
IgA
122
Does a monoclonal Ab have identical or different Ab molecules?
Identical
123
What do B cells have on their surface to recognize antigens?
Surface immunoglobin
124
What do T cells have on their surface to recognize antigens?
T-cell receptors
125
What must the immune system develop to avoid reaction against the body's own components?
- Non-reactivity
| - Tolerance to self-reactivity
