Immunology Flashcards
1
Q
How is the scattered immune system around the body connected
A
By blood and lymph
2
Q
What is the immune system’s role in protection
A
- Protects the entire body at all times
- From pathogens
- From altered body cells (cancer)
3
Q
How can our immune system turn on us
A
Autoimmune disorders
Foreign tissues: transplant or graft
4
Q
What are the two types of immunity
A
Non-specific/innate and specific/adaptive immunity
5
Q
What is the body’s first line of defense
A
Non-specific/innate
6
Q
Which response does not need to recognize the pathogen and why
A
Non-specific/innate because it’s the same response every time it sees a pathogen
7
Q
Which response requires the recognition of the pathogen
A
Specific/adaptive
8
Q
What happens to the response when the adaptive immune system sees the same pathogen again
A
It’s a faster response
9
Q
What are the three types of discoveries in science
A
Accidents of nature, leaps of faith, serendipity (happy accidents)
10
Q
What are the components of the immune system
A
Lymphoid organs, immune cells and secretions of immune cells
11
Q
What are the two types of lymphoid organs
A
Primary lymphoid organs and secondary lymphoid organs
12
Q
What are primary lymphoid organs
A
Sites where stem cells divide and immune cells develop
13
Q
What are secondary lymphoid organs
A
Sites where most immune responses occur
14
Q
What are the immune cells
A
Leukocytes
15
Q
What are the two primary lymphoid organs
A
Bone marrow (yolk sac and fetal liver in embryo)
Thymus
16
Q
What happens in bone marrow
A
Blood cells are produced here: B cells and immature T cells and where B-cells mature
17
Q
What is in the thymus and what happens in it
A
Contains T cells, scattered dendritic cells, epithelial cells and macrophages
Site where T cells mature, atrophies after maturity
18
Q
Where is the thymus located
A
Above the heart
19
Q
What are the 3 secondary lymphoid organs and what is their main function
A
Lymph nodes, spleen, lymphoid nodules
Sites where most immune responses occur
20
Q
What are lymph node characteristics
A
Scattered throughout the body
Filter microbes
Macrophages in nodes phagocytize microbes that enter lymph
21
Q
What are spleen characteristics
A
Largest lymphoid organ
Removes microbes and old erythrocytes
22
Q
What are lymphoid nodules characteristics
A
Tonsils
Peyer’s patches and MALT
Appendix
23
Q
Where do the immune cells travel in the body
A
Travel in the blood and lymphatic vessels (90% circulatory 10% lymphatic)
24
Q
What are the types of T cells and what lineage do they come from
A
Come from lymphocytes
Cytotoxic T-cells CD8+
Helper T cells CD4+
Regulatory T-cells CD4+
25
What lineage do macrophages and dendritic cells come from
Myeloid (neutrophil, monocyte, eosinophil, basophil)
26
Function of eosinophils
Destroy parasites and participate in immediate hypersensitivity reactions
27
Function of basophils
Release a variety of chemicals, histamine, prostaglandins (similar to mast)
28
Functions of mast cells
Release chemicals involved in inflammation, histamine
29
Function of neutrophils
Phagocytes, releases chemicals involved in inflammation
30
Function of monocytes
Become macrophages and dendritic cells (phagocytes) after entering into tissues
31
Function of lymphocytes
Serve as recognition cells in specific immune responses and are essential for all aspects of these responses
32
Function of B cells
Initiate antibody-mediated immune responses by binding specific antigens to the B cell’s plasma membrane receptors, which are immunoglobulins
Upon activation: transformed into plasma cells which secrete antibodies
Present antigen to helper T-cells
33
What is the function of cytotoxic T cells
Binds to antigens on plasma membrane of target cells and directly destroys the cells
34
Function of Helper T cells
Secrete cytokines that help activate B cells, cytotoxic T cells, NK cells and macrophages
35
Function of NK cells
Bind directly and non specifically to virus-infected cells and cancer cells and kill them
36
Difference between cytotoxic T cells and NK cells
NK = non-specific
CT = specific
37
Function of plasma cells
Secrete antibodies
38
Where are plasma cells produced
Peripheral lymphoid organs; differentiate from B cells during immune responses
39
Function of macrophages
1. Phagocytosis
2. Extracellular killing via secretion of toxic chemicals
3. process and present antigens to helper T cells
4. Secrete cytokines involved in inflammation, activation and differentiation of helper T cells and systemic responses to infection or injury
40
Function of dendritic cells
Phagocytosis, antigen presentation (professional APC)
41
Where are dendritic cells found
Almost all tissues and organs; microglia in the central nervous system
42
What cells are produced in the bone marrow
1. neutrophils
2. Basophils
3. Eosinophils
4. Monocytes
5. Lymphocytes (mature in bone marrow (B and NK) and thymus (T cells) but activated in peripheral lymphoid organs)
6. Macrophages (reside in almost all tissues and organs)
7. Mast cells (reside in almost all tissues and organs)
43
What is non-specific/innate immunity
Ability of the body to defend against microbes and other foreign substances without recognition of the invading pathogen
44
What is the innate first line of defense
Physical barriers
45
What are innate second line of defense
Cellular and hum oral factors
46
What are the physical barriers in the first line of defense
Skin
Additional physical and mechanical barriers
Chemical and microbiological barriers
47
In what way does skin as a first line of defence create an unpleasant environment for microorganisms
Water resistant, prevents entry of foreign substances
48
In what way do additional physical and mechanical barriers as a first line of defence create an unpleasant environment for microorganisms
Tight junctions in epithelia, mucus, hair and cilia
49
In what way do chemical and microbiological barriers act as a first line of defence create an unpleasant environment for microorganisms
Secretions (sebum, lysozyme, gastric juice)
Normal flora (tears and saliva)
50
When are second lines of defense used
If barriers are breached
51
Does the second line of defense in innate immunity have memory
No
52
What are the humoral factors in the second line of defense
Inflammation and fever
Antimicrobial substances (acute phase reactants like cytokines and complement)
Interferons
53
What are the cellular factors in the second line of defense in innate immunity
Phagocytic cells (neutrophils, macrophages, dendritic cells)
Cells with inflammatory mediators (basophils, mast cells, eosinophils)
Natural killer cells
54
Which cells are involved in inflammation
Neutrophils, basophils, eosinophils, macrophages and mast cells
55
Which cells are involved in phagocytosis
Neutrophils, macrophages and dendritic cells
56
Which cells release cytokines
Macrophages Helper T cells
57
What are the 4 distinct signs and symptoms of inflammation
Redness
Heat
Pain
Swelling
58
What are the 3 stages in inflammation
1. vasodilation
2. Emigration of phagocytes
3. tissue repair
59
Why is vasodilation an important part of inflammation
1. Widening of blood vessels allows more blood flow to the site
2. Increased permeability of capillaries allows substances to go to the damaged site
60
What do humoral substances discourage and how
Microbial growth or spread of pathogens
Interferons, complement and iron binding proteins
61
What is the function of type 1 interferon
Prevents viral replication
62
What is a complement
A large family of plasma proteins with multiple functions (30 different plasma proteins participate in the cascades
63
What can complement activation lead to
1. Recruitment of inflammatory cells
2. Opsonization of pathogens
3. Killing of pathogens
64
What is an example of an iron binding protein and what does it do
Transferrin: keeps iron away from an infection to prevent dividing
65
What are natural killer cells (NK cells)
A class of lymphocytes, similar to cytotoxic T cells
66
What is the function of natural killer cells
They target virus-infected cells and cancer cells
67
Similarities between NK cells and cytotoxic T cells
They attack and kill these target cells directly after biding to them
68
Differences between NK cells and cytotoxic T cells
NK cells are not antigen specific and do not need to recognize a specific antigen
69
What do all normal uncleared body cells express and what is it recognized by
MCH class 1 proteins that are recognized by the NK cells (won’t kill the cell)
70
When will the NK cell be activated and release agents that kill a cell
When a cell does not have or has an altered MHC class 1 protein
71
What happens t old RBCs
They are phagocytosed in the spleen
72
What do phagocytes do
Non-specifically engulf microbial invaders
73
What are the types of microbial invaders
Fixed-tissue macrophages
Neutrophils
Monocytes-macrophages and dendritic cells
74
Steps of phagocytosis and intracellular destruction of a microbe
1. Endocytosis of microbe from outside of cell
2. Phagosomes formation
3. Lysosome combines with phagosomes to form phagolysosome
4. Release of end products into or out of cell
75
How does the phagocyte recognize microbes
detects unique, conserved structures that are essential to microbial physiology (molecular signatures of infection)
Pathogen-associated molecular patterns (PAMPs)
76
How are PAMPs recognized by the immune system
By immune system receptors called pattern recognition receptors including Toll-like receptors on the surface of the macrophage
77
What are the types of PAMPs
1. Lipopolysaccharide of gram negative bacteria
2. Peptidoglycan of gram positive bacteria
78
What are toll-like receptors
A family of highly conserved transmembrane receptors essential for microbial recognition via PAMPs
79
What are the types of toll-like receptors
Extracellular domain for recognition of pathogens
Intracellular signalling domain
80
What starts the process of inflammation
Neutrophils signals more neutrophils to go to site of infection
Macrophage TLR
Bacteria PAMPs activate macrophage
81
What are the three steps of emigration of phagocytes
Chemotaxis
Marginations
Diapedesis
82
What are chemotaxis and the types of chemotaxis
Chemically stimulated movement of phagocytes
Chemokines/chemoattractants (chemicals that attract phagocytes)
83
What is margination if emigration of phagocytes
Sticking to endothelial cells
84
What is diapedesis in emigration of phagocytes
Phagocytes move across capillary wall
85
What happens to neutrophils in the process of killing bacteria
They die
86
What are Neutrophil extracellular traps
Made of processed chromatin bound to granular and selected cytoplasmic proteins which come from lyses neutrophils
87
Why are neutrophil extracellular traps sticky
To trap bacteria in place
88
What is pus made of
A mixture of dead bacteria and neutrophils
89
What is an immunogen
Material that induces an immune response
90
What are the characteristics on an antigen
1. Can be the whole cell or a part of a cell
2. Can be non microbial
91
What are examples of non-microbial antigens
Pollen, egg whites, incompatible blood cells, transplanted tissues
92
What is an epitope
The part of the antigen that is recognized by the immune cells
93
What happens to the dendritic cell after it picks up bacteria
Goes back through lymphatic system and not capillaries
94
How does innate immunity shift to adaptive immunity
Via antigen presentation by phagocytes
95
What is specific/adaptive immunity and what are the types
Mediated by antibodies or cells
1. Humoral (antibody-mediated immunity)
2. Cell-mediated immunity
96
What is the adaptive immunity humoral aspects
Involves B cells
- Transform into plasma cells
- Synthesize and secrete antibodies
- Memory B cells
97
What are the aspects of adaptive immunity cell mediated immunity
Involves cytotoxic T cells
Kill infected body cells, cancer cells, foreign cells
98
What are the two molecular classes of the major histocompatibility complex (MHC)
1. MHC-I expressed on all uncleared cells
2. MHC-II expressed on antigen presenting cells
99
What types of people have the same MHCs on their cells
Only identical twins
100
When do T-cell receptors recognize antigens
Only when they are associated with MHC-II proteins (part of the antigen presentation process)
101
What are the steps of an antigen presenting cell engulfing an exogenous
1. Ingest antigen
2. Digestion into peptide fragments
3. Synthesize and package MHC-II molecules
4. Bind peptide fragments to MHC-II
5. Insert antigen-MHC-II complexes on plasma membrane
102
What are two antigen characteristics
Reactivity: antigen binds specifically to the antigen that provoked it
Immunogenicity: can provoke an immune response by producing antibody to that antigen
103
What are antigen presenting cells (APC)
MHC-II + antigen
1. Interdigitating dendritic cell/professional APC
2. Macrophage
3. B lymphocyte (B Cell)
104
What is specific/adaptive immunity (definition)
Ability of the body to defend against specific microbes and foreign substances, involves memory from previously encountered antigens
105
What cells are involved in specific/adaptive immunity
B and T cells (recognize specific foreign material to be attacked)
106
What is an antigen
Any molecule that can trigger an adaptive immune response against itself or the cell bearing it
107
What are the three stages of a typical adaptive immune response
1. Recognition of an antigen by lymphocytes
2. Lymphocyte activation
3. Attack launched by the activated lymphocytes and their secretions
108
What cells are involved in the adaptive humoral response and what do they do
B cells
Transform into plasma cells and produce and secrete antibodies
Use antibodies and complement to kill
109
What cells are involved in the adaptive cell mediated immunity and what do they do
Cytotoxic T cells
Kill infected cells
110
How can biological processes shut off controls (which is necessary)
In immune response this involves displacement of CD28 from B7 by CTLA4 or PD-1
111
What are the events required for the activation of Helper T Cells
1. Specific recognition (MHC-II + peptide on APC - T cell receptor on T helper)
2. Co-reception (CD28 on APC and B7 on T helper)
3. Cytokine release from APC (stimulates T helper cell)
112
How does the activation of B cells in secondary lymphoid organs done
APC activates T helper cell
T helper cell releases cytokines
CD40 receptors
B cell sees antigen and gets activated by cytokines
113
What group are antibodies part of
Group of proteins called globulins (immunoglobulins Ig)
114
What is the structure of antibodies
Contain 4 polypeptide chains
- Two identical heavy chains
-Two identical light chains
115
What are the two distinct regions with heavy and light chains
1. Variable region
2. Constant region
116
What is the variable site of an antibody
Antigen binding site (FAB region)
117
What is the constant region of an antibody
Same in all antibodies of a class (FC region)
118
What are he 5 classes of antibodies
IgG, IgA, IgM, IgD, IgE
119
What are the characteristics of IgGs
Most numerous, cross the placenta, move to all parts of the body
120
What are the characteristics of IgA
Found in MALT, breast milk (most effective at fighting bacteria)
121
What are the characteristics of IgM
First formed, complement activation (complement cascade)
122
What are the characteristics of IgD
Prenatal
123
What are the characteristics of IgE
Allergy response
124
What are the aspects of antibody-mediated immunity
It is carried out by B cells
It undergoes clinal selection to produce things
125
In the presence of a microbe, where do B cells in anti by mediated immunity get activated
Spleen, lymphoid nodule or lymph nodes
126
What does antibody mediated immunity undergo colonial selection to produce
Plasma cells which secrete specific antibodies
Memory cells which allow faster response if antigen is seen again
127
How can antibody immunity be acquired
Actively or passively
128
What is actively acquired antibody immunity
The person’s own immune system responds to microbe, long lasting protection (memory cells are involved)
129
What are the types of active antibody immunity
Natural (develops when a person is exposed to an antigen by chance)
Artificial (develops when a person is purposefully exposed to an antigen ex: flu vaccine)
130
What is passive antibody immunity
The person receive antibodies from another person or animal temporary protection NO memory cells are involved
131
What are the types of passive antibody immunity
Natural: IgG from mother to fetus across placenta, IgA in breast milk
Artificial: Receive serum containing antibodies from person or animal that has been vaccinated
132
What is the resistance in active immunity due to
The body’s contact with microorganisms, their toxins or other antigenic components (from an infection or vaccine)
133
What could a vaccine consist of
Small quantities of living or dead pathogens
Small quantities of toxins or harmless antigenic molecules derived from the microorganism or its toxin
134
What are the functions of antibodies
1. neutralizing antigen
Agglutination of antigens
Precipitation of antigens
Activating complement
Opsonization
Antibody-dependent cellular cytotoxicity
135
What does neutralizing an antigen by an antibody entail
Antibody binding to toxin prevents us from being infected
136
What does agglutination of an antigen by an antibody entail
Glueing them together so that the microbes are easier to phagocytose
137
What does precipitating an antigen by an antibody entail
Facilitating phagocytosis
138
What does activating complement by antibody entail
First complement protein inactive until it binds to microbe that sets off cascade of activity to eventually produce membrane attack complex
139
What does Opsonization by an antibody entail
Making the microbe more apparent to phagocyte
140
How is antibody dependent cellular cytotoxic done by
Via cytotoxic T cells
141
How must lymphocytes gain immunocompetence
Develop antigen receptors
142
What do B cells produce
Antibodies
143
What do T cells produce
Cytotoxic T cells, CD8+ cells, Helper T cells and CD4+ cells
144
What does it mean for lymphocytes to gain immunocompetence
They must develop antigen receptors
145
How do lymphocytes gain immunocompetence (2 steps)
1: RAGs (recombination activating genes)
2: TdT (terminal deoxynucleotidyl transferase) which adds single or multiple nucleotides at ends
146
Why is there a higher concentration of IgGs over IgMs after second infection
IgM’s are produced first and are best for activating complement system but not best for moving around the body because of large size
147
Under normal circumstances, will the body create antibodies to self antigens
No
148
What is important in tissue/organ transplant rejection
MHC (major histocompatibility complex)
149
Which kinds of people do not have unique MHCs
Identical twins
150
When does immune tolerance develop and why
Fetal and early postnatal life because of colonial deletion or colonial inactivation of cells that match body antigens
151
What must T cells be able to recognize and what happens if they can’t
MHC class II molecules
Will be destroyed if they can’t
152
What should T cells not recognize and what will happen if they do
Self proteins, MHC-class I molecules
Destroyed
153
What percentage of T cells produced will be destroyed
95%
154
What are endogenous antigens produced by
Body cells
155
What are the steps of infected or antigen cells
Synthesis of molecules
Binding of molecules
Packaging of antigen complexes
Insertion of antigen complexes int plasma membrane
156
What are the types of molecules infected body cells synthesize, bind, etc
MHC-I molecules
157
What is an exogenous antigen
Foreign material, comes from outside of the body
158
What types of molecules do antigen presenting cells synthesize, bind, etc
MHC-II molecules
159
How does and APC activate B cells or cytotoxic T cells
By the release of cytokines
160
What are the factors that alter resistance to infection
1. Protein-calorie malnutrition (greatest contributor worldwide)
2. Pre-existing disease (infectious or non infectious can predispose the body to infection)
3. Sleep deprivation (associated with decreased immune function)
4. Modest exercise and physical conditioning (net beneficial effects on the immune system and host resistance)
161
What are immunodeficiency diseases resulted from
Weak, under active or impaired immune systems
162
What are two types of immunodeficiency diseases
SCID (severe combined immunodeficiency disease)
AIDS (acquired immunodeficiency syndrome)
163
What is SCID
A group of related diseases that arise from an absence of both B and T cells and in some cases NK cells
164
What is AIDS
Infects and kills s helper T cells resulting in impaired immune responses to infectious organisms
165
What are examples or harmful immune responses
Tissue/Graft rejection
Transfusion reactions
Allergy (hypersensitivity)
Autoimmune disease
Excessive inflammatory response
166
What types of proteins on the graft cells in transplants differ from the recipient
MHC-I
167
What kinds of proteins on the macrophages in a transplant differ from the recipient
MHC-II
168
What happens in a graft or organ transplant rejection
Recipient’s T cells recognize these MHC proteins as foreign and their cytotoxic T cells with the aid of helper T cells kill cells bearing foreign MHCs
169
How can one avoid tissue or organ transplant rejection
Radiation to eliminate dividing cells
Drugs that kill actively dividing lymphocytes (decrease T cell population)
Cycloprorine blocks cytokine production from helper T cells
170
How is illness caused in blood transfusion reactions
When RBCs are destroyed during blood transfusion
171
Why do erythrocytes lack MHC proteins
They dont have a nucleus
172
What structures on RBCs function as antigens
Plasma membrane proteins and carbohydrates
173
What are the two types of allergic reactions
Immediate hypersensitivity
Delayed Hypersensitivity (12-72 hours after exposure)
174
Where are allergic symptoms usually localized
localized to the site of antigen entry
175
What causes anaphylaxis
If large amount of mast cells chemicals enter the circulation, systemic symptoms may result and cause severe hypotension and bronchioles contraction
176
How can anaphylaxis cause death
Due to circulatory and respiratory failure
177
What is inappropriate immune attack triggered by in some cases
Body proteins acting as antigens
178
What is the autoimmune attack mediated by and directed against
MB: autoantibodies and self-reactive T cells
DA: body cells that contain these proteins
179
What are examples of autoimmune diseases where inappropriate immune attack is triggered by body proteins acting as antigens
Type 1 diabetes Melkite’s
Rheumatoid arthritis
Multiple sclerosis
Myasthenia gravis
