Microbiology CH 13 Flashcards
(148 cards)
1
Q
What is the body’s ability to recognize and react to a specific invader?
A
Specific Immunity
2
Q
Is specific immunity when the body reacts to the H1N1 influenza virus rather than the H5N8 influenza virus?
A
Yes
3
Q
What are the 4 elements of specific immunity?
A
- It’s a ‘smart’ system
- It’s acquired and developed over time
- A response includes organs
- It’s triggered by specific antigens
4
Q
What does it mean when the body has a ‘smart’ system?
A
Has a “memory” to respond rapidly to an infection the second time it happens
5
Q
What does a response entail?
A
Includes B and T lymphocytes
6
Q
What is anything that stimulates a specific immune response called?
A
Antigen
7
Q
What is the 3D region of an antigen that is actually recognized by the immune system called?
A
Epitope
8
Q
What part of the LPS (lipopolysaccharide) is recognized by the immune system?
A
Particular set of sugars on polysaccharide
O-Antigen
9
Q
How many epitopes does an antigen have? What is it recognized by?
A
Multiple epitopes; recognized by different things
10
Q
What type of antigens are found on invaders that exist outside host cells?
A
Exogenous antigens
11
Q
What are 2 invaders with exogenous antigens?
A
- Bacterial infections
- Parasitic worms
12
Q
How does the immune system encounter exogenous antigens/the invaders?
A
Encounters them directly
13
Q
What type of antigens are found on invaders that exist inside body cells?
A
Endogenous antigens
14
Q
What are 2 “invaders” with endogenous antigens?
A
- Viruses once they’ve entered the host cell
- Obligate intracellular parasites
15
Q
Can the immune system detect endogenous antigens directly? Why?
A
No, because they’re not floating around in the body
16
Q
What must happen for endogenous antigens to be detected by the immune system?
A
Antigens must be incorporated into the host cell membrane
17
Q
What antigens are naturally found on host cells?
A
Autoantigens
18
Q
Why do immune cells need to ignore autoantigens?
A
Because autoantigens label cell as “self”
19
Q
What happens when immune cells recognize autoantigen cells?
A
Immune cells that recognize autoantigens are destroyed
20
Q
What happens if immune cells DON’T destroy autoantigens?
A
Leads to autoimmunity
21
Q
What are proteins used by the immune system to identify, bind to, and help attack invading organisms called?
A
Antibodies
22
Q
What are antibodies composed of? What types of ‘chains’ are there and how many?
A
Four polypeptides connected to each other by disulfide bridges
23
Q
What do antibodies look like?
A
“Y” shape, stem, hinge, and 2 arms
24
Q
What part of the antibodies are constant? Which parts are variable?
A
Constant - Stem, hinge, lower part of arms
Variable - Upper parts of arms
25
What is another name for antibodies?
How many different types are there?
Immunoglobins
5 different types
26
What happens when an antibody neutralizes a pathogen?
1000 antibodies bind to a virus, making its surface crowded and makes it unable to attach to target
27
What happens when an antibody agglutinates a bunch of cells together?
Each antibody can bind to 2 cells, creating a clump
28
What happens when an antibody oxidizes a target?
Involves recruitment of other proteins
29
How can antibodies eliminate threats indirectly?
Marks invaders for targeting by immune cells
30
What is one of the types of leukocytes (WBCs) that is made by stem cells in bone marrow?
Lymphocytes
31
Which Lymphocytes mature in bone marrow and which ones mature in the thymus?
Bone Marrow - B Lymphocytes
Thymus - T Lymphocytes
32
Where are B Lymphocytes mainly found? Where do a few circulate?
Mainly found in Lymphatic Organ, few circulate in the blood
33
How many different B cells does an individual have present at any given time?
10^11
34
When do B Lymphocytes activate?
Activates when a 'correct' antigen has been recognized
35
When activated, what are B Lymphocytes known as?
Plasma Cells
36
What 2 things does a plasma cell do?
1. Makes lots of copies of itself
2. Makes and secretes many copies of specific antibody (the one that recognized the 'correct' antigen)
37
Where do T Lymphocytes (T cells) circulate?
Blood and lymph
38
How many different types of T cells are present at any given time for any individual?
~10^11
39
What does different types mean (for T cells)?
Have receptors that recognize different (random) antigens
40
How are T cells activated?
By binding to an antigen that is presented on an MHC molecule on a host cell
41
What 2 things do activated T cells do?
1. Makes lots of copies of themselves
2. Secrete cytokines that affect other cells
42
What cells are known as T8 or CD8 cells?
Cytotoxic C cells
43
When Cytotoxic C cells are active, what is secreted? What do they do and what happens?
Secrete cytokines that trigger replication
(Makes more copies of that particular 'model' of Tcyt cell)
44
When Cytotoxic C cells are active, how do they kill bad cells? What type of cells does this include?
Kills bad cells by inducing apoptosis
1. Cancerous cells or tumors
2. Cells infected by a virus of bacterium
45
What cells are known as T4 or CD4 cells?
Helper T cells
46
When Helper T cells are active, what is secreted? What do they do?
Secrete cytokines to help activate B cells and Tcyt cells
47
When Helper T cells are active, what do they differentiate into? What does each one assist?
Differentiates into:
Type 1 (TH1) assist Tcyt cells
Type 2 (TH2) assist B cells
48
What is a type of protein that is found on the surface of body cells called?
Major Histocompatibility Complex
49
What does MHC allow body cells to do?
Allows body cells to alert the immune system that there is an invader present
50
How does MHC allow the body cells to alert the immune system?
Holds antigens on surface of cell to 'show' it to T cells
51
Where is MHC-I found? This means everything except what kind of cells?
Found on membranes of all nucleated body cells
Everything except RBCs
52
What kind of antigens does MHC-I display?
Endogenous antigens
53
What cell does MHC-I "present" to? What's the message?
1. Presented to Cytotoxic T cells
2. Message: "Look what I made"
54
What's the 2 possible meaning of MHC-I's presentation? What is the result of each one?
1. Meaning: "There is an intracellular pathogen inside the cell"
2. Result: Activation of cell-mediated immune response, where T-cell kills the infected body cell
3. Meaning: "There isn't any pathogen, everything is fine"
4. Result: No immune response
55
Where is MHC-I made? What happens while its in the ER?
Made at RER
Stuff from inside cell attached to it while in ER
56
What packages MHC-I? What is MHC-I carrying and where does it go?
Golgi body packages MHC-I carrying epitopes, and sends it to cell membrane
57
What happens when the vesicle fuses?
MHC-I/epitope complex is presented to the outside
58
In what cells is MHC-II present? What are 2 examples of these cells?
Antigen-presenting cells (APCs)
1. Phagocytic cells like macrophages
2. B Lymphocytes
59
What antigens does it display and to what cells?
Exogenous antigens to helper T cells
60
What's the message of MHC-II? What is the meaning and what is the result?
Message: "look what I ate"
Meaning: An extracellular pathogen or toxin is present
Result: Activation of Humoral Immune Response where antibodies are made and system is at full alert
61
_______ happens by an Antigen-Presenting Cell (APCs)
Phagocytosis
62
What do APCs always have? What do epitopes in the phagosome do?
Always have vesicles
Epitopes 'identify' what the invader is
63
What happens when the vesicle and phagosome fuse?
Exposes MHC-II to pathogen epitope
64
What happens when vesicles with MHC-II/Epitope fuse with the cell membrane?
Displays epitope to outside world
65
What is the immune response against exogenous antigens?
Humoral Response
66
Exogenous antigens are things that invade the host, but don't go into the host cell. True or False?
True
67
The Humoral Response occurs in the blood via what?
Antibodies
68
What are 3 antibodies that make up the Humoral response? What do they compose of?
1. B Cells: Plasma and memory cells
2. T Cells: Type 2 Helper Cells
3. Major Histocompatibility Complex 2
69
What are the 5 steps in the Humoral Response?
1. Antigen presentation
2. Helper cell differentiation
3. Clonal Selection
4. B Cell Activation
5. Memory
70
What's the first step to Humoral Response?
APCs take in invading cell by phagocytosis, displays bits of antigen on surface
71
Where does APC travel to? What happens once it travels here?
Travels to Lymph node then looks for helper T cell whose receptor can bind to antigen
72
Only a T cell with the ___________________________
Only a T cell with right receptor will bind to presented antigen
73
What's the second step to Humoral Response?
Interaction between APC and TH cell causes release of interleukins that activate Helper T cell which triggers change into TH2, which helps activate B cells
74
What are B cells coated in and what do they have? What are B cells also known as and what do they make?
B cell is coated with unique antibodies, which has specific antigens
B cells are also APCs which make MHC-II
75
What's the third step to Humoral Response?
C cell's surface antibodies capture an antigen, cell 'eats' antigen and connects it to its MHC-II, which is presented to any TH2 cell with right TCR
76
What is it called when a TH2 cell and B cell both bind the same antibodies?
Signal to the body
77
What does the 'signal to the body' say?
B cell can make antibodies that will bind to the antigen
78
What is the process that selects for a particular 'version' of the B cell?
Clonal Selection
79
What is the fourth step to Humoral Response?
TH2 binds to B cell and secretes a cytokine that 'activates' the B cell
80
What does activation mean for the Humoral Response? What do they make?
Activation means cell undergoes many rounds of mitosis, making many copies of relevant B cells
Lots of plasma cells are made which secrete antibodies (same antibodies are bound to antigen)
81
What other cells are also made as a result of activation? Describe their function. Where do they circulate and for how long?
Memory cells - aren't actively producing antibodies, but still contains information for making them
Circulates in body for years
81
What are the 3 main steps of Humoral Response?
1. Antigen is presented to T cell by APC
2. T cell then looks for matching B cell
3. B cell is activated to make many antibodies and memory cells
82
How long does the response take the first time you're exposed to a pathogen? Why?
Takes a while, because immune system has to 'learn' to recognize the antigen
83
How long does the response take after the first time? Why?
Faster, because immune system is 'remembering' rather than 'learning'
84
What is the immune response against endogenous antigens?
Cell-mediated response
85
What does the cell-mediated response target?
Infected or abnormal cells
86
What cell types are used in Cell-mediated response? Which cells are not used? Which MHC type is used?
TH1 and Tcyt
No B cells
MHC-I used
87
What are the 5 steps of Cell-mediated response?
1. Antigen presentation by host cell
2. Clonal selection
3. Differentiation of TH ---> TH1
4. Tcyt activation
5. Memory
88
All human cells except RBCs do what?
Constantly sample their own interiors to present random bits and pieces on MHC-I
89
After interiors are sampled, what happens if the bits-and-pieces are normal? What if they're wrong? What T cells do identification?
If normal host antigens, they won't trigger a response
If wrong antigens, this will be identified by T cells
1. Tcyt cell
2. TH cell
90
How is Tcyt cells activated?
Tcyt binds to MHC-I/antigen complex
91
What do Tcyt cells do?
Can recognize the 'problematic' antigen
92
What happens after Tcyt activation?
Interleukins released, inflammatory response
93
After interleukin release, what do Tcyt cells do? What 2 things are a result of this?
Tcyt cells will bind to infected cells and kill them
1. Induction of Apoptosis
2. Production of Tumor Necrosis Factor
94
What happens when TH cells bind? What is secreted afterwards?
Converted to TH1
95
What happens to the Tcyt and TH cells while some TH cells bind to be converted to TH1 cells?
Undergo replication
96
What does undergoing replication mean?
(HINT: 2 meanings)
1. Increased response
2. Memory will be formed, stronger more rapid response next time
97
What is acquired and improved during an individual's life?
Specific Immunity
98
What is gained in response to antigens introduced via vaccine?
Artificially-Acquired Immunity
99
What is a response to antigens via Humoral or Cell-Mediated Response?
Active Immunity
100
What does active immunity mean? What does passive immunity mean?
Active - Receiving antigen to train immune system
Passive - Receive antibodies only
100
What is a response to antigens via antibodies that came from another individual?
Passive Immunity
100
What is the introduction of artificially-acquired immunity?
Immunization
101
What is gained in response to antigens encountered in daily life?
Naturally-Acquired Immunity
101
Can Immunization be both active or passive?
Yes
102
What is Variolation?
Grinding up scabs with mild smallpox and used it to infect children
103
What are the pros and cons of Variolation?
Pros: Protected most recipients from getting severe smallpox
Cons: 1-2% of recipients died and recipients are still contagious
104
What is used by giving individuals specific antibodies against a thing?
Passive Immunization
105
Does passive immunization train the immune system? Why?
No, since antibodies aren't associated with specific B cell
106
What are the pros and cons of passive immunization?
Pros: Quick response to exogenous antigens (ex: Botulism treatment)
Cons: No memory from B or T cells and once antibodies are degraded, there's no more immunity
107
What did Edward Jenner do?
(Include virus name)
Showed people who got cowpox (Vaccinia virus) did not get smallpox
108
What is infecting people with non-harmful version of pathogen called?
Vaccination
109
Name 6 vaccines developed at the end of the 20th century
1. Polio
2. Measles
3. Mumps
4. Rubella
5. Chicken Pox
6. Hepatitis A and B
110
Vaccination allowed us to ___________ smallpox. What is the next target?
Vaccination allowed us to eradicate smallpox.
Polio is the next target
111
By WHO stats, what does it estimate every year? How much can be prevented by vaccination
(HINT: 3 answers)
1. Vaccination saves 2-3 million lives every year
2. 10 million children younger than 5 die every year
3. One quarter of these can be prevented by vaccination
112
Since the launch of the Global Polio Eradication Initiative in 1988, how much has Polio decreased? How many new cases in 1988 vs 2007? What makes it challenging?
Worldwide incidence decreased by 99%
1988 - 350,000 new cases
2007 - 1,300 new cases
World events make it challenging
113
What is the idea that a population is what needs to be protected from a disease, rather than any single individual?
Herd Immunity
114
Herd immunity confers protection to what people? Why?
People who are not immune
Person who is susceptible never comes in contact with diseased individual, they will never get sick
115
What does herd immunity require? What is the 'bad' alternative to herd immunity?
High rate of immunization
Global pandemic to get everybody infected
116
What qualities of a disease makes it so different diseases require different levels of immunization to confer herd immunity?
Infectiousness of disease and method of transmission
117
Immunization has a very _____ risk. What does it depend on?
Immunization has very LOW risk
Depends on vaccine type
118
What are 2 reasons fear is a big factor regarding immunization?
1. Mistrust of vaccine administrators for religious reasons
2. Mistrust of vaccination due to disinformation
119
What are 3 factors that make it hard to vaccinate?
1. Populations are in areas that are hard to reach
2. High cost to develop vaccines
3. Some organisms naturally resist vaccination
120
List 2 organisms that resist vaccination
1. HIV
2. Common cold
121
True or False. The research about the link between vaccines and autism by Andrew Wakefield are fabricated.
True
122
What are the 4 types of vaccines?
1. Attenuated vaccines
2. Killed/inactivated vaccines
3. Toxoid vaccines
4. RNA vaccines (new)
123
What is when a live organism that has been modified is introduced to a person?
Attenuated vaccine
124
What can attenuation be through?
Genetic modification or by selecting mutants that are avirulent
125
What does modification do to an organism?
Makes organism avirulent, so it cannot cause the disease
126
What are the 4 pros of attenuated vaccines?
1. Contains replicating microbes, which means lots of antigens and strong immune response
2. Viral vaccines trigger cell-mediated immune response, which leads to memory
3. Bacterial vaccines trigger humoral response, which leads to memory
4. Can contribute to herd immunity, because they infect those around them with attenuated version so those people are now protected
127
What are the 3 cons of attenuated vaccines?
1. Can lead to disease, especially in immunocompromised
2. Can cross placenta, meaning pregnant women should not get them
3. Modified viruses can occasionally revert to wild-type or mutate to virulent form
128
What can be either whole killed microbes or subunits or fragments of a microbe?
Killed/Inactivated Vaccines
129
What is important during production of a killed vaccine?
Antigens are not altered too much
130
What kind of antigen is used in killed vaccines? What does it do?
Exogenous antigens
Can't infect the cell, won't trigger cell-mediated response, but still stimulate hormonal response
131
What's the pros of killed vaccines?
Safer than liver vaccines since it can't replicate or mutate into virulent form
132
What are the 3 cons of killed vaccines?
1. Not infectious ---> can't generate herd immunity
2. Not replicating ---> fewer antigens means you might have to get booster doses
3. Not effective at training the immune system
133
What do we use to vaccinate against a specific toxin?
Toxoid Vaccines
134
What is a toxoid?
Modified version of toxin
135
List 2 diseases toxoid vaccines are important for
1. Tetanus
2. Diphtheria
136
How many doses of toxoid vaccines do you need? What is its response rate like? What kind of immune response is triggered?
Multiple doses, has a lower response rate
Only very specific immune response is triggered
137
What 2 pieces of information do you need to make an mRNA vaccine?
1. What does an antigen on the surface of pathogen look like?
2. What is an RNA sequence that would generate that structure?
138
With the given information, what do you do to mRNA to produce a vaccine?
Synthesize mRNA and encapsulate it in a lipid (so it can cross into cells)
139
After encapsulation, what are the 4 steps to making an mRNA vaccine?
1. Cells produce (and release) many copies of antigen
2. Stimulates Humoral immune response, to make more antibodies
3. To neutralize any virion that comes into the body
4.No attachment = no entry = no synthesis = no assembly = no release = no infection
140
When did the first clinical trials for RNA vaccines start?
2003
141
Was RNA vaccines used in COVID-19 Pandemic? Why?
No, due to lack of funding for rapid development and deployment
142
How effective are RNA Vaccines? What is the efficacy in preventing hospitalization?
Incredibly effective, 90%+ efficacy in preventing hospitalization
143
How safe are RNA vaccines? What are the side effects like?
Incredibly safe
Mild side effects are common to all vaccines
More serious side effects very rare
144
For the serious side effects of RNA vaccines, what are the cases like? What is it less common than?
10.69 cases per 100,000 persons for highest risk group
Much less common than severe illness without the vaccine
