Immunology Exam Flashcards
(205 cards)
1
Q
What are the 2 categories of immunology?
A
- Non-specific (Innate) 2. Specific (Adaptive)
2
Q
Which immune response is antigen-independent?
A
Non-specific
3
Q
How fast will non-specific and specific immune response work?
A
Non-specific is immediate and specific is slower with lag time.
4
Q
Which type of immunology has immunologic memory?
A
Specific
5
Q
What is the largest contributor to WBCs?
A
Neutrophils are 60-65%
6
Q
What activates neutrophils and what do they do?
A
Activated by tumor necroses factor and they are rapidly phagocytic cells
7
Q
What % of WBCs are basophils?
A
0.1-0.3%
8
Q
What triggers basophils?
A
They are histamines triggered by IgE in allergic reactions.
9
Q
What type of cell is similar to a basophil, and what makes it different?
A
Mast cells are basophils that are found in tissues.
10
Q
What do eosinophils do?
A
They are involved in destruction of parasites.
11
Q
Where are monocytes found?
A
Circulate in blood
12
Q
What do monocytes develop into once they enter tissue?
A
Macrophages or dendritic cells
13
Q
What are the primary functions of macrophages?
A
- Phagocytosis
2. Antigen presentation
14
Q
How are macrophages stimulated?
A
By cytokines
15
Q
Which immune response are dendritic cells involved in?
A
Adaptive
16
Q
Where are T lymphocytes differentiated and how long do they live?
A
Thymus
Long lived
17
Q
What are the 3 types of T cells and their functions?
A
- T helper - coordinate entire immune response
- T cytotoxic - destroy infected self cells
- T regulatory - suppress immune response
18
Q
What can B lymphocytes differentiate into?
A
- Plasma cells
2. Memory B cells
19
Q
Which cells produce antibodies?
A
Plasma cells
20
Q
How are memory B cells formed?
A
Specific to antigens during primary immune response
21
Q
What type of cells are Natural Killer cells?
A
Cytotoxic lymphocytes
22
Q
How do NK cells work?
A
Create holes in cell membrane
23
Q
What do NK cells attack?
A
Cells that have been infected by microbes NOT microbes themselves
24
Q
Which part of immune system are NK cells a part of?
A
Non-specific
25
What mediates activity and communication between WBCs?
Cytokines
26
What are the functions of cytokines?
1. Induce other cells of immune system
2. Stimulate antigen dependent and independent cells
3. Induce chemotaxis and diapedesis
27
What are the 4 types of cytokines?
Lymphokines, interleukins, tumor necrosis factor, and interferons
28
What are peripheral lymphoid organs?
Sites where lymphocytes are gathered to contact antigens
29
What are primary lymphoid organs?
Where hematopoietic stem cells mature
30
What is the function of lymph nodes?
Store and circulate lymphocytes, remove particles from lymph
31
What is the function of the spleen?
Filter blood an destroy old RBCs
32
What is MALT?
Mucosal associated lymphoid tissue
33
What is SALT?
Skin associated lymphoid tissue
34
What is the thymus responsible for?
Immunogenesis in children, T lymphocytes maturation, thymic education, thymic selection
35
When does thymus reach peak size and peak activity?
Peak SIZE - puberty
| Peak ACTIVITY - childhood
36
What is thymic education?
Differentiation of thymocytes
37
What do thymocytes differentiate into?
CD-4 (T helper) and CD-8 (cytotoxic)
38
What are the two types of CD 4 cells?
TH-1 (cell mediated response)
| TH-2 (activate B cells)
39
What is positive selection vs negative selection?
Positive - thymus selects T cells that are functional to distribute to peripheral tissue
Negative - non-functional cells enter apoptosis
40
What are the first line defenses in non specific immunity?
1. Skin
2. Mucous membranes
3. Antimicrobial substances
4. Normal flora
41
What is the most difficult barrier for microbes to penetrate?
Skin
42
What antimicrobial substances are part of non-specific immunity?
Sweat, lysozymes, acid in stomach
43
What do lysozymes do?
Degrade peptidoglycan (unique to bacteria)
44
What are the sensor systems of the non-specific immune system?
Toll-like receptors, complement
45
Where are toll-like receptors located?
On a variety of immune cell types
46
What do toll-like receptors do?
Recognize compounds unique to microbes, allows cell to send cytokines to other systems
47
What is complement?
Series of proteins always present in blood that act in conjunction with adaptive immune responses
48
What are phagocytes?
Cells that specialize in engulfing and digesting microbes
49
What two classes of phagocytes participate in non specific immunity?
Macrophages and neutrophils
50
Where are macrophages found?
Always present in tissue
51
How do NK cells identify cells to kill?
Won't kill cells identified by MHC1 surface proteins
52
What are the three parts of inflammation?
1. Injury/invasion
2. Dilation of blood vessels
3. Fever
53
What are the characteristics of adaptive immunity?
1. Specificity
2. Self recognition
3. Memory
54
What is the humoral response?
Eliminates antigens that are extra cellular (ex bacteria in bloodstream)
55
What is the cell-mediated response?
Deals with antigens residing within a host cell (ex virus infected cell)
56
What is the structure of antigens?
Large carrier molecule with epitopes projecting from surface
57
What are exogenous antigens?
Those that have entered body from outside
58
What are endogenous antigens?
Those that have been generated within the cell
59
What are super antigens?
Attach onto sides of binding site instead of MHC groove
60
What does it mean when antigens are cross reactive?
They elicit and bind to the same antibody
61
When is an individual tolerant to self antigens?
Before the immune system is fully mature
62
What happens when a superantigen binds to the MHC?
T cells go on an unregulated rampage, uncontrollably releasing regulatory molecules in toxic amounts
63
What is the major histocompatibility complex?
Surface protein found on surface of all nucleated cells and platelets
64
What does MHC do?
Display "self" molecules that will be ignored by T cells or "non self" molecules that will be recognized by T cells
65
What are the 2 classes of MHC proteins and what are their functions?
1. MHC1 - present proteins/antigens from inside cell
| 2. MHC2 - present antigens from outside cell
66
Where are MHC1s found?
On all nucleated cells
67
Where are MHC2s found?
ONLY on antigen presenting cells
68
What do MHC1s display?
Ordinary surface proteins and "abnormal" proteins on surface of virus infected cells or tumor cells for inspection by cytotoxic T cells
69
What do MHC2s display?
"Non self" proteins to be recognized by helper T cells
70
Where are activated dendritic cells found?
In tissues that are in contact with environment
71
When do macrophages present antigens?
Early in infection
72
What activates macrophages?
Presence of antigen
73
What do activated macrophages produce?
Interleukin-1
74
How do macrophages process antigens?
Digest antigenic material, present antigenic epitopes on macrophages surface, presented antigen then recognized by helper T cells
75
When are activated B cells used?
Later in infection as APC
76
What must helper T cells recognize in order to produce lymphokines?
MHC2
77
What do activated helper T cells regulate?
Both cell mediated (t cell) AND humoral (b cell) immunity
78
What is required in order for B cells to produce antibodies?
Must interact with activated helper T cell
79
What mediates cell-mediated immunity?
T cells
80
Which type of MHCs are found on Antigen presenting cells?
Both
81
Where are activated dendritic cells found at?
In tissues that are in contact with the environment
82
What will activate a macrophage?
The presence of an antigen
83
Macrophages have increased numbers of what?
Lysosomes
84
Macrophages produce a cytokine called interleukin-1 - what does it do?
Induce a fever and activate other cells
85
After a macrophage digests an antigen, what will the macrophage do?
It will present the epitopes on the macrophage surface in combination with MHC proteins
86
The epitope on the macrophage surface is recognized by what?
Helper T cells which activate helper T cells
87
What do helper T cells need to do to produce lymphokines?
They must recognize MHC2
88
Activated helper T cells regulate what type of immunity?
Cell-mediated (and humoral)
89
What do B cells need to do to produce antibodies?
They must interact with activated helper T cells
90
When will T cells produce antibodies?
Never
91
T cells never interact with what?
Free antigens
92
Inactive T cells can or cannot migrate into tissues?
Cannot
93
Activating T cells requires what 2 things?
1. Must encounter antigen presented on cell in antigen-MHC complex 2. Must be concurrently stimulated by other molecules
94
Activation of T cells leads to what?
Formation of specific effector T cell types
95
What are the 3 roles of activated T Cells?
1. Proliferate, develop into different effector cells. 2. Bring antigen to naïve T cells. 3. Release lymphokines
96
What do lymphokines do?
They act to recruit other cell types particularly macrophages
97
What are the 2 types of T cells?
CD4+ aka T helper cells, and CD8+ aka T cytotoxic cells
98
What is the role of CD4+ (T helper) cells?
To judge the significance of antigen presented by APCs
99
After a CD4+ recognized an antigen, what will it do?
Release cytokines that stimulate development of B cells and other T cells
100
What are the two subsets of CD4+ cells?
TH1 and TH2
101
TH1 and TH2 cells judge antigens presented by what?
TH1 - macrophages TH2 - B cells
102
What will the TH1 cells do after recognizing the antigen?
Stimulate the macrophage
103
What will TH2 cells do after recognizing the antigen?
They activate B cells to produce antibodies
104
What is the most common T cell?
CD8+ aka cytotoxic cells
105
What do CD8+ cells do?
They induce apoptosis in self cells infected with virus or other microbes
106
How do CD8+ cells know what self cells to attack?
Those that present antigens on MHC1 molecules
107
What do T suppressor cells do?
Block induction and activity of T helper cells and B cells
108
What stimulates T suppressor cells?
Cytokine interleukin 2
109
The type IV hypersensitive reaction occurs when?
When effector T cells regulate delayed allergic reactions
110
What is homeostasis?
A balance between the 2 T lymphocyte populations and it is critical for immunocompetence
111
What are lymphokines?
Cytokines released by lymphocytes that act as chemical messengers and activate other cell types
112
What will macrophage activation factor MAF do?
Activates macrophages and allows them to act as cytotoxic cells that non-specifically kill tumor cells
113
What will macrophage migration inhibitory factor MIF do?
Inhibits random migration of macrophages
114
What are interleukins?
They are lymphokines and are proteins secreted by different types of leukocytes that are involved in cell-to-cell communication
115
What are interferons?
A type of lymphokine that elicits a virus-nonspecific antiviral activity
116
Humoral immunity is mediated by what?
B lymphocytes
117
What do B cells do in response to an antigen?
Proliferate then differentiate into plasma cells and then they produce antibodies. Some B cells also form memory cells.
118
Antibodies are produced by ____ cells and differentiated by ____
Plasma cells, B lymphocytes
119
Where are antibodies found at?
In the blood serum, and the surface of B lymphocytes
120
What will antibodies on the surface of B lymphocytes allow for?
Interaction with specific antigens
121
What is agglutination?
Role of an antibody - causes cellular clumping
122
What is precipitation?
Role of an antibody - non-cellular clumping
123
What happens when an antibody joins with an antigen and forms an antigen/antibody complex?
Complex is recognized by phagocytic cells
124
What is an antitoxin?
An antibody with ability to neutralize a specific toxin
125
What is opsonin?
Any molecule that acts as binding enhancer for the process of phagocytosis
126
An antibody is made of what type of chains?
A heavy chain and 2 light chains
127
What joins the chains of antibodies?
Disulfide bonds
128
What is the fragment binding portion of an antibody that binds to antigens called?
Fab
129
What part of the antibody determines antibody class?
Fc
130
What is the first and second class of antibodies to be produced in response to antigens?
First is IgM, second is IgG
131
What does the Ig class of antibody stand for?
Immunoglobulin
132
What is the most abundant immunoglobulin?
IgG
133
How will IgG antibody work?
Agglutinates, precipitates, and acts as antitoxin
134
What happens when multiple IgGs bind to surface of an antigen?
A specific complement protein binds to the Fc region to begin complement cascade
135
What immunoglobulin can pass the placental barrier and provide passive immunity to fetus?
IgG
136
What is the shape of the IgG?
Monomer aka gamma globulin
137
What immunoglobulin is largest?
IgM
138
When will fetuses be able to produce IgM?
After 3 months
139
How will the IgM work?
Agglutination, precipitation, and most effective at activating complement cascade
140
Where are IgA antibodies found?
In body secretions like saliva, mucus, milk, tears
141
How will IgA exist in blood?
As monomer with valence of 2 (2antigens can bind to it)
142
How will IgA exist when secreted?
As a dimer with valence of 4 (4antigens can bind to it)
143
What are IgE antibodies involved in?
Allergy
144
How do IgEs work?
Bind to mast cells and release histamines
145
How detectable are IgEs?
They are barely detectable in normal blood, most are bound via Fc region to mast cells and basophils
146
What is the role of IgDs?
Unknown
147
Where are IgDs found at?
In low levels in serum
148
Where are complement proteins at and how long will it take to activate them?
They are always circulating and can be quickly activated
149
What will complement proteins do when activated?
Attach to cell surface and form membrane attack complex (MAC)
150
Complement binding can cause what 3 things to happen?
1. Prepares cell for phagocytosis 2. Can release active substances 3. Can lyse cell
151
What are the 2 complement pathways?
1. Classical 2. Alternative
152
What is necessary for classical and alternative complement pathways?
Classical = antibody IgG or IgM needs to bind to an antigen Alternative = No antibody binding to an antigen needed
153
What type of immune responses are the complement pathways involved in?
Both specific and non-specific
154
What happens if the complement system is not controlled?
Can lead to vascular damage and initiateion of coagulation
155
How is the complement system slowed?
Serum proteins slow complement by binding to protein surfaces
156
If complement activation is overwhelming what happens?
Serum proteins fail
157
During the primary response to an antigen how long does it take for the adaptive immune system to respond?
1 week or more
158
During the week it takes for the adaptive immune system to respond to a primary exposure to an antigen, what takes over?
Non-specific immunity
159
What are the first and second antibodies that are produced during adaptive immune response?
1=IgM, 2=IgG
160
What does it mean to have antibodies that are T cell independent or dependent?
Independent - do not require presentation, rather B cells respond diretly to antigen. Dependent - do require presentation to helper T cells
161
What stimulates memory cells?
Secondary response to antigens
162
What is the level of IgG antibody during a secondary response to an antigen?
Higher, longer lasting
163
How much antigen is needed to elicit an immune system response with a secondary response to an antigen?
Less antigen is needed than with a primary response to an antigen
164
What was the first vaccination given?
Edward Jenner in 1796 gave cowpox to pretect against smallpox
165
Vacca is Latin for what?
Cow
166
Immunity can be acquired in what 2 ways?
Naturally or artificially
167
What are the 3 types of vaccines we can get?
1. Inactivated or killed 2. Live attenuated 3. Subunit (fragments of the cell or virus)
168
What is an inactivated or killed vaccine like?
Unable to replicate but retains immunogenicicty of infectious agent
169
What is the advantage of inactivated vaccines?
It can't revert to dangerous form
170
What is a live attenuated vaccine like?
It is weak and unable to cause disease t replicates in recipient causing an immune reinfection with undetectable or mild disedase
171
There are 4 types of hypersensitivity to the immune system - how many come from antibodies and how many from T cells?
3 from antibodies and 1 fro T cells
172
Type 1 hypersensitivity is the fastest - what does it come from?
Allergic reactions
173
Allergic reactions bind to what?
IgE which are on mast cells
174
What happens the 2nd time an individual is exposed to an allergen?
The sensitized mast cell degranulates releasing histamine and other vasoactive substances
175
Type 2 hypersensitivity is cytotoxic reactions - the antigen and which antibody bind where?
Antigen and IgG antibody bind on cell surfaces
176
What happens to cells with the antigen and IgG bound to them?
They are destroyed by phagocytosis or complement
177
Type 2 or cytotoxic diseases are mostly due to what?
Blood transfusions with wrong blood type
178
Type 3 hypersensitivity is aka immune complex reactions - what is happening?
Antigen-antibody complexes from in the blood and are not completely removed by macrophages and these complexes get lodged in capillaries and this leads to vasodilation and it attracts leukocytes and this leads to inflammation and tissue death
179
What makes type 4 hypersensitivity different than the first 3?
It is cell mediated (T cell) not antibody mediated
180
How does type 4 hypersensitivity work?
T cell interacts with the presented antigen and proliferates and secretes lymphokines and macrophages are attracted and host cell is destroyed
181
What is tolerance?
An immune system state associated with self-recognition where the immune system will not respond to self antigens
182
Tolerance to self antigens is developed when?
During fetal development
183
Can people become tolerized to other antigens later in life?
Yes
184
Give an example of how someone can become tolerized to a self antigen later in life?
Oral tolerization
185
What is autoimmunity?
When the immune system reacts to self antigens
186
Autoimmunity is characterized by what?
The production of autoantibodies
187
Name 5 triggers of an autoimmune response
1. Infection 2. Response to drugs 3. Cross reactivity with bacterial antigens 4. hormones 5. breakdown in immune responses
188
Many autoimmunity mechanisms have been identified but how will they interact with the immune network?
This is not yet known
189
What is serology?
The use of serum antibodies to detect and measure antigens, or conversely the use of antigens to detect serum antibodies
190
What is a titer?
Can give information regarding amount of antibody present following disease, can give important information regarding a person's current immunity to diseases
191
What is agglutination test?
The interaction between antibody and antigen results in cross-linking o cells
192
What is precipitation test?
Interaction between antibody and a soluble antigen in aqueous solution forms a lattice that develops into a visible precipitate
193
What is immunodiffusion test?
As antibody and antigen diffuse toward one another a visible line will form in agar
194
What is complement fixation test?
Indicator system is RBCs from sheep. In the presence of hemolysins and complement the RBCs lyse. If an antibody-antigen complex is present, the antibody will bind complement and no lysis will occur
195
Capsular swelling is aka?
Quellung reaction
196
What is the capsular swelling test?
Swelling of the capsule surrounding a microorganism after reaction with an antibody
197
What is the neutralization test?
Specific antibodies (antitoxins) present will neutralize effect of toxin
198
What type of antibodies are used in ELISA test?
Two: 1 is specific to antigen and 2 is coupled to an enzyme
199
What are the steps in an ELISA test?
Coat wall with antigen. Add patient's serum. Then add anti-human antibody wth an enzyme attached to it. Then add substrate to enzyme
200
What happens in ELISA test?
If the patient has the antibody to the antigen they will bind to the wall and the antihuman antibody with the enzyme will bind to the antibody, and when the substrate to the enzyme is added a color change will happen. No color change if the serum has no antibody to the antigen
201
What is "in vivo" serology?
Testing for antibodies in the body
202
What part of the body is tested for schick test?
Intracutaneous skin
203
What will Schick test scan for?
Diphtheria toxin
204
What will a reaction and no reaction to Schicks test mean?
Reaction indicates patient has no antibodies and no reaction indicates the patient has antibodies
205
What type of test is the tuberculin skin test?
Not antibody mediated, this is a cell-mediated response, specifically type 4 hypersensitivity
