Unit 3 - Adaptive Immunity Flashcards
(124 cards)
1
Q
Which cell is the link between the adaptive and innate immune systems?
A
Dendritic cells
2
Q
Identify what the innate and adaptive aspects of the dendritic cells are
A
Innate = phagocyte Adaptive = antigen-presenting cell
3
Q
What is the name for the non-specific features that are recognized by the innate immune system?
A
PAMPs
- the same pattern COULD be on multiple bacteria species
4
Q
What is the name if the specific molecule that may be used by the adaptive immune system to identify a specific pathogen?
A
An antigen
5
Q
What is on the surface of lymphocytes that is able to bind to specific antigens?
A
Receptors
6
Q
Which cells are lymphocytes that are part of the adaptive immune response (2)?
A
- B-cells
2. T-cells
7
Q
True or False:
Toxins can be ligands that bind to receptors
A
True
8
Q
What are immunoglobulins?
A
Receptors on B-cells that bind to antigens
9
Q
What happens to a B-cell that binds to the antigen that it’s been looking for?
A
It become PARTIALLY activated!
- a T-helper cell would make it FULLY activated
10
Q
What happens to the B-cell and it’s immunoglobulins (Ig’s) if it is fully activated by a helpter T-cell?
A
The receptors are secreted as antibodies
11
Q
True or False:
Each individual B-cell or T-cell only recognizes one unique antigen
A
True
12
Q
What section of the antigen does a b-cell or t-cell receptor recognize/bind to?
A
The epitope
13
Q
What are the things that epitopes must have in order to be functional?
A
- Minimum 4-6 amino acids
- 3D shape
- Multiple epitopes
14
Q
True or False
The amino acid sequence of an epitope is more than the 3D shape
A
False
- 3D shape is more important than the amino acid sequence
15
Q
True or False
All antigens are immunogens
A
False
- Immunogens always produce an immune response
- Not all antigens mount an immune reponse
16
Q
Define immunogenicity
A
The ability of a substance to elicit an immune response
17
Q
What are 4 factors that contribute to the immunogenicity of an antigen or immunogen?
A
- Chemical composition
- Molecular size
- Foreignnes of the molecule
- Extrinsic factors (adjuvants)
18
Q
Which molecule classes are more immunogenic, proteins, carbohydrates or lipids - why?
A
Proteins
- lipids are too fluid, they don’t have a rigid shape
- carbs have are weakly immunogenic
19
Q
What do perfumes and colognes contain that cause an allergic reaction?
A
Aromatic compounds
- these can be recognized by the immune system and stimulate an allergic response
20
Q
What size of molecule is too small to generate an immune response?
A
< 1000 Da
< 10,000 Da are poorly immunogenic
21
Q
What is a Hapten?
A
A small antigen
- cannot initiate an immune response
22
Q
What is the function of a carrier?
A
It is a large substance that binds to a Hapten
- now the Hapten is large enough to stimulate an immune reponse
23
Q
What is the name of the structure, when a hapten binds with a carrier?
A
Hapten-Carrier Complex
24
Q
True or False:
The likelihood of a hapten binding (“conjugating”) to a carrier is high
A
False
- the likelihood of a hapten binding is relatively low
25
What does it mean if a person is sensitized to a hapten?
It means that the hapten has been bound to a carrier
| - it will elicit an immune response
26
What happens if a person has been exposed to a conjugated hapten (that elicited an immune response), and then the next time the person is only exposed to the hapten (no carrier)?
The immune system MAY respond to unconjugated hapten = allergy
- this happens with some metals
- when people develop allergies to metal
27
Is it possible that some sugars, amino acids and drugs (or drug metabolites) are haptens?
YES!
| - for instance penicillin
28
Explain why some people have a drug allergy to penicillin.
Penicillin is too small on its own
- when drug degrades, it can react with (bind with) proteins
- this makes it large enough to elicit a response
- immune system will keep a memory of the penicillin allergy
29
In the case of a penicillin allergy, what is the hapten and what is the carrier?
```
Hapten = penicillin
Carrier = protein
```
30
Why can someone get hemolytic anemia due to an antibody production against penicillin?
RBCs can have conjugated penicillin attached to the surface
- antibodies attach to the surface and mark it
- complements will lyse the cell b/c of antibody markers
31
True or False:
| In order for a molecule to be immunogenic, it should be static, > 10,000 Da and have multiple epitopes
True
32
Which structure has greater immunogenicity (aromatics, linear, or bent)?
```
Aromatics = most
Bent = middle
Linear = least
```
33
What happens to lymphocytes that recognize self-antigens during maturation?
They are removed!
| - we don't want lymphocytes attacking ourselves
34
Give an example of molecular mimicry
Microbes that have evolved protein epitopes that resemble human proteins
35
True or False:
| Your adaptive immune system will not react to tumor cells
True!
- tumor cells are your OWN cells
- adaptive immune system will NOT react to "self"
36
Why is a Group A Streptococcus infection so deadly?
Strep cells components mimic the shape of human proteins in heart, kidneys, joints, etc
- autoantibodies will react to BOTH strep AND human cell structures
= you make antibodies against yourself!
= Rheumatic fever
37
What does cross-reacting mean?
Antibodies that target similar epitopes on unrelated substances
38
Give an example of when cross-reacting occurred
1940s
- women were diagnosed with STD syphillis
- actually had lupus
39
Explain WHY lupus was diagnosed as syphillis
- Cardiolipin is found on surface of bacteria (such as syphilis)
- it is also on the surface of mitochondria
- For patients that have LUPUS, antibodies are made that CAN GO INSIDE THE CELL, and they find the cardiolipin on the mitochondria, not on the bacteria
= Auto-antigen!
40
True or False:
| Botulism is an exotoxin, so we can make antitoxins against it
True!
41
How does serum sickness occur?
1. Expose horse to botulism
2. Collect serum from horse
3. Expose patients to serum (with antibodies against toxin)
4. Patients got sick! (Cytokine storm)
5. Patients reacted to the foreignness of the horse serum components
42
What is an autograft?
Transplant from self-self
43
What is an isograft?
Transplant from genetically identical twin-twin
44
What is an allograft?
Transplant from the same species
45
What is a xenograft?
Transplant from a different species
46
How are auto-antigens able to generate an immune response?
Modification to normal proteins
| - stimulation of autoimmune response can cause normal proteins to become recognized as antigens (auto-antibodies)
47
What are allo-antigens?
Antigens derived from other people
48
What are two example of allo-antigens?
1. Blood transfusion (blood group antigens = A, B, and Rh)
| 2. Organ transplant (human leukocytes antigens ("tissue type"))
49
What is biobanking?
Hematopoietic stem cells are collected from umbilical cord blood, and stored if there is a risk of an inherited hematological disease
50
What are three example of autografting?
1. Biobanking (hematopoietic stem cells are saved from umbilical cord)
2. Cancer patient (during remission) can have bone marrow harvested - so during relapse, they can recieve their OWN bone marrow
3. Patient's blood can be banked prior to an elective surgery
51
True or False:
| Group A Strep uses molecular mimicry to develop rheumatic fever
True
52
True or False:
| Lymphocytes that are auto-reactive are eliminated, but not all of them
True
| - not 100% elimination!
53
What is an example of an extrinsic factor that make a molecule more immunogenic?
Adjuvants
54
Define adjuvant
Chemical agent that stimulates the local immune response
55
What are two common adjuvants?
1. Aluminum salts
| 2. Squalene
56
What are three mineral salts that act as vaccine adjuvants?
1. Aluminum hydroxide
2. Aluminum phosphate
3. Calcium phosphate
57
What cell is the bridge between the innate and adaptive immune systems?
Dendritic cells
58
Where do B-cells mature?
Bone marrow
59
Where do T-cells mature?
Thymus
60
What are the two lymphocytes of the adaptive immune system?
1. B-cells
| 2. T-cells
61
Which cells are antigen presenting cells (3)?
1. Dendritic cells
2. Macrophages
3. B-cells
62
Describe the steps in which antigen presenting cells present an antigen (4).
1. Phagocytose pathogen
2. Digest proteins into peptides
3. Receptors attach to peptides (antigens)
4. MHC-II presents antigen on the outside of the cell
63
True or False:
| Neutrophils are APCs
False
- neutrophils are NOT antigen-presenting cells
- if neutrophils can clear an infection FIRST, then you will not have to make antibodies
64
On which cells will you find MHC-I?
All nucleated human cells
65
On which cells will you find MHC-II?
Some white blood cells
66
What is the name of the receptor that binds to MHC-II, which cell carries this receptor?
CD4
| - helper T-cells have CD4
67
What cytokine does the APC secrete in order to activate the helper T-cell?
IL-1
68
If an APC is presenting an antigen, what binds to the antigen and what binds to the MHC-II complex?
Antigen + T-cell receptor
| MHC-II + CD4
69
What do activated helper T-cells secrete that activates B-cells?
IL-2
70
Once a B-cell is activated, what does it secrete?
Antibodies!
71
What is the first thing that an activated B-cell does?
Clonal expansion
| - rapidly proliferatees
72
What two kinds of cells can activated B-cells differentiate into?
1. Memory B-cells
| 2. Plasma B-cells
73
What is the difference between memory b-cells and plasma b-cells?
```
Memory = retains antibodies for a later infection
Plasma = released antibodies for current infection
```
74
What kind of b-cells contributes to immunological memory?
Memory B-cells!
| - these live for a long time
75
Why do memory B-cells elicit a faster immune response for secondary infections?
Because they do NOT have to be activated by a helper T-cell
76
True or False:
| If you get a stem cell transplant, you have to get re-vaccinated for EVERYTHING!
True
77
What is the interleukin that activates both B-cells and cytotoxic T-cells?
IL-2
78
True or False:
| Helper T-cells participate in killing pathogens
False
| - helper T-cells signal but do NOT participate in actual killing
79
True of False:
| Cytotoxic T-cells participate in killing pathogens
True
| - they directly attack the pathogen cells
80
What are the 4 functions of antibodies?
1. Agglutination
2. Neutralization
3. Opsonization
4. Complement activation
81
What is agglutination (with antibodies)?
Antibodies that can stick together, causing the target to clump
82
What is neutralization (with antibodies)?
Antibodies bind to the surface of a pathogen/toxin and prevent it's function
83
What is opsonization (with antibodies)?
Cells bound by antibodies are more often phagocytozed
84
If a cell is infected with a VIRUS, what molecule will present it?
MHC-I
85
If an antigen is presented on MHC-I, what cell will come and attack it?
Cytotoxic T-cell
86
True or False:
| RBCs have MHC-I on their surface
False
| - only nucleated cells present MHC-I
87
True or False:
| B-cells have MHC-I and MHC-II on their surface
True!
88
What are two examples of intracellular microbes?
1. Salmonella
| 2. Tuberculosis
89
What are the two classes of antigens?
1. Those expressed within normal cells - presented on MHC-I
| 2. Those dervived from phagocytosis by APCs - presented on MHC-II
90
If a cell presents an antigen on MHC-I, what response is triggered?
Cytotoxic T-cells
91
True or False:
| Cytotoxic T-cells can be triggered WITH or WITHOUT helper T-cells
True
| - as in the case of presentation on MHC-I
92
Define clonal population
Population of cells with an identical genetic makeup
93
True or False:
| Lymphocytes undergo genetic changes during maturation
True
94
What is the name of genetic recombination of B-cells?
VDJ recombination
| - variable diverse joining
95
By mixing and matching the genes in each cell, how many different epitopes are lymphocytes able to recognize?
3 x 10 ^ 11 possible epitopes
96
Is it possible to have an immunity to HIV or ebola?
Yes!
| - we just have to find out which VDJ recombination is responsible for it
97
What happens when a lymphocyte finds the antigen that it's been looking for all it's life?
Clonal expansion
98
During a primary infection, what do you make for future infections?
Memory B-cells
99
What happens if you expose someone to antigens?
You create immunological memory!
| - they create antibodies
100
What happens if someone is infected with a pathogen, and you give them antibodies?
Antibodies will bind to pathogen
| - no immunological memory
101
What is the difference between active and passive immunity?
```
Active = creates antibodies through immune response; IMMUNOLOGICAL MEMORY
Passive = received antibodies; NO IMMUNOLOGICAL MEMORY!
```
102
What is an example of natural active immunity?
You are exposed to a pathogen and you create antibodies to fight off the infection
103
What is an example of artificial active immunity?
You receive a vaccine and you create antibodies to fight off the antigen (without the active pathogen)
104
What is an example of natural passive immunity?
You receive antibodies from your mother's breastmilk or through the placenta
105
What is an example of artificial passive immunity?
You receive an anti-toxin
| - preformed immunity made by another person or animal
106
What kind of immunity is an anti-venom?
Artificial passive immunity
107
What kind of immunity is immunoprophylaxis?
Artificial active immunity (same as vaccine)
| - administer an agent to prevent disease before exposure has occurred
108
What are 4 sources of antigens?
1. Killed whole cell / inactivated virus
2. Live, attenuated cells / virus
3. Proteins or other antigenic molecules purified from pathogen
4. Genetically engineered antigen
109
What are the pros and cons of using a killed / inactivated pathogen in a vaccine?
```
Pros = almost always dead and safe
Cons = pathogen does not multiply, therefore a higher dose and booster shots are required
```
110
What are examples of pathogens that are administered via killed / inactivated vaccines?
- Salk Polio
| - Influenza
111
What are the pros and cons of using an attenuated pathogen in a vaccine?
```
Pros = multiplies somewhat; confers long-lasting protection
Cons = risk of reversion
```
112
What is reversion?
Getting a serious infection after receiving an attenuated vaccine
113
What are examples of pathogens that are administered via attenuated vaccines?
- Tuberculosis
- Oral polio vaccine
- Diptheria
- Tetanus
114
If a pathogen is highly contaigous, what kind of vaccine method do you NOT want to use?
Attenuated
- in case there is reversion
- could spread rapidly
115
What are the pros and cons of using a purified molecule / subunit vaccine?
```
Pros = no living pathogen
Cons = Antigen may change shape during purification
```
116
What are examples of pathogens that are administered via purified molecules / subunit vaccine?
- Anthrax
| - Hepatitis B
117
Why would we use a purified molecule or subunit vaccine INSTEAD of a killed or attenuated vaccine?
In cases of pathogens that are HIGHLY deadly
| - just in case not all of the pathogen are killed or attenuated
118
What are the pros and cons of using recombinant proteins in vaccines?
```
Pros = cheap, safe
Cons = Clonal and pathogen can evolve resistance easily
```
119
What is an example of a pathogen administered via recombinant protein vaccine?
Hepatitis B
120
What makes a good vaccine?
1. Low level of adverse side effects
2. Protect against exposure
3. Should stimulate B-cell and T-cell response
4. Should produce memory
5. Should not require numerous boosters
6. Should be inexpensive
121
True or False:
| The best things to administer via vaccine are antigens.
False
- we want to give immungoens
- b/c these stimulate an immune response
- not all antigens do!
122
At what percentage is herd immunity considered effective?
95% herd immunity
123
What is herd immunity?
Large scale immunization to prevent epidemics
124
If 95% of the population has been immunized, do we need to vaccinate anymore?
Yes! B/c if we skip a generation it can easily become and epidemic again
