Exam 1 (Lectures 3/4) Flashcards
1
Q
True or False: Antibodies are glycosamines
A
False - glycoproteins
2
Q
True or False: All the below mentioned are POSITIVE outcomes of antibody production
-Neutralize viruses and toxins
-Accelerate clearance of bacteria
-Use for clinical assays
-Use as therapies to kill tumor cells
A
True
3
Q
True or False: Allergies, Immune Complex Disease, and Autoimmunity are NEGATIVE outcomes of antibody production
A
True
4
Q
What’s the major difference between immunoglobulins and antibodies?
A
- Immunoglobulin (Ig): General term for all antibody molecules
- Antibodies: Immunoglobulins made by TERMINALLY DIFFERENTIATED B LYMPHOCYTES in response to foreign antigen
5
Q
True or False: The constant region defines the isotype of the heavy chain
A
False - the conserved region defines isotype of heavy chain
6
Q
True or False: In an antibody, both light chains and heavy chains are identical
A
True
7
Q
What determines the heavy chain type?
A
The amino acid
8
Q
A
9
Q
Which part of the antibody binds to the antigen?
A. Fab Region
B. Constant Region
C. Fc Region
D. Fragment of Antigen Binding
A
A.) Fab Region and
D.) Fragment of Antigen Binding
10
Q
Which part of the antibody forms idiotype? the isotype?
A
-Idiotype = The Fab Region
-Isotype = Fc Region
11
Q
Fab binds to ___ antigen while F(ab)2 binds ___ antigens
A
1, 2
12
Q
Where is the Constant Region located: the Fab Region or the Fc Region?
A
Fc Region
13
Q
Which region of the antibody contains biological activity: the Fab region or crystallized fragment region?
A
Crystallized fragment region (Fc)
14
Q
True or False: Opsonization and helping to lyse microorganisms are examples of biological activity carried out by the Fc Region
A
True
15
Q
What region of the antibody is found on BOTH the heavy and light chains, is encoded in the genome, and is same between antibody molecules
A
The Constant Region
16
Q
Which Ig is the major Ig isotype in serum and crosses the placenta?
A
IgG
17
Q
Where is the Variable Region located?
A
Portion of heavy and light chain that binds epitope
18
Q
IgM is secreted by plasma cells as ____ and is joined by ____ chains
A
pentamer; J chains
19
Q
True or False: IgM binds 10 antigens at a time
A
False - Despite 10 F(ab) it only binds 5 antigens at a time
20
Q
What is the first Ig synthesized in response to an antigen?
A
IgM
21
Q
Which Ig is a dimer in mucus secretions and is linked by J chains?
A
IgA
22
Q
What is the major Ig found in external secretions (saliva, sweat, tears)?
A
IgA
23
Q
True or False: IgE has lowest serum concentration
A
True
24
Q
True or False: IgE is an agglutinating antibody and a complement-activating Ab
A
False - it is NEITHER
25
Which Ig protects host from parasitic infections by interaction with eosinophils?
IgE
26
Which Ig mediates Type 1 Hypersensitivity Responses (allergies)?
IgE
27
Which Ig is the only to be susceptible to proteolytic degradation?
IgD
28
Which Ig is a marker of B Cell differentiation?
IgD
29
Two fates of Ig molecules?
1) Secreted (terminally differentiated B cells) 2) Anchored in the B cell membrane + acts as antigen receptor for cell
30
___: The inverse of the highest dilution of a substance that reacts with a fixed amount of target material
Titer
31
Three clinical uses of serology?
1) Obtain specific diagnosis using antibody response - 4x increase in titer
2) Screen population
3) Monitor treatment efficacy
32
____: Measure of the ability of a test to exclude non-diseased cases
_____: Measure of the ability of a test to identify diseased cases
Specificity: Measure of the ability of a test to exclude non-diseased cases
Sensitivity: Measure of the ability of a test to identify diseased cases
33
When are SPECIFIC tests most helpful?
When tests are....
positive or negative?
to rule in or rule out?
SPECIFIC TESTS are most helpful when test is (+) to rule in
34
Which tests is likely to identify those who do NOT have disease: Specific Tests or Sensitive Tests?
Specific Tests
35
True or False: PCR (RNA Amplification) is an example of sensitive tests while an at-home pregnancy tests, EIA and antigen testing are specific
PCR = specific test
Pregnancy tests, EIA, antigen = sensitive test
36
What test is most helpful when it's negative (to rule out) and is likely to identify everyone with the disease?
Sensitive Tests
37
Screening tests should have high ____ while confirmatory tests should have high _____
sensitivity; specificity
38
If antibodies are so specific, why do get false positives?
Similar antigens/epitopes may cross-react
39
Are ELISA's and Enzyme Immunoassay (EIA) qualitative or quanitative?
Enzyme-Linked ImmunoSorbent Assay (ELISA): Quanitative
EIA: Qualitative
40
True or False: ELISA are used to find antigen or antibody in patient’s serum/secretions
False - Enzyme Immunoassay (EIA) are used to find antigen or antibody in patient’s serum/secretions
41
True or False: Immunofluorescence Assay is good for localizing antigen using fluorescently labeled antigens
True
42
Direct IFA detect antigen located in the ___ while IFA detects antigen located in ____
tissue; serum
43
What type of Immunofluorescence Assay would you use for biopsy/peripheral blood/rabies?
Direct IFA
44
What type of IFA is associated with:
- Nuclear antigens (autoimmunity)
-Infectious agents
-Lupus
Indirect IFA
45
What are the clinical uses of Flow Cytometry?
1) CD4:CD8 ratios in HIV
2) Analyze tumor cells for markers
3) Analyze peripheral blood for % of cell types
46
True or False: Fluorescence Activated Cell Sorting (FAC) is used to isolate and purify specific cell populations AND sort cells for use in transplant/lab
True
47
True or False: Both Flow Cytometry and Fluorescence Activated Cell Sorting use fluoresceinated antibodies to measure:
1) Cell size and number
2) Density of cell surface molecules
3) Number of cells with a certain cell-surface molecule
True
48
What does precipitation in a secondary binding test tell you about the antigen?
What does agglutination in a secondary binding test tell you about the antigen?
Precipitation means that antigen is SOLUBLE
Agglutination means that the antigen is INSOLUBLE
49
____ Antibody: reacts with soluble antigen resulting in formation of insoluble precipitate
Precipitin Antibody (Ab)
50
What type of antibody reacts with an insoluble antigen, results in clumping
Agglutinin
51
What are the two types of precipitation reactions?
1) Immunodiffusion Tests (Ouchterlony Test)
2) Radial Immunodiffusion Tests
52
What do Ouchterlony and Radial Immunodiffusion Tests have in common? (hint: antigen)
Both use SOLUBLE antigens
53
True or False: Immunodiffusion Tests (Ouchterlony Test) are qualitative and used to test/ID parasitic infections
False -
While immunodiffusion tests are qualitative, they are used clinically to test/ID fungal diseases
54
Are Radial Immunodiffusion Tests qualitative or quantitative? Clinical uses?
Radial Immunodiffusion Tests, a type of precipitation reaction, is quantitative and used to determine [IgG isotypes] in serum
55
Clinical uses of Direct Agglutination?
What type of antigens are used in Direct Agglutination?
Blood Typing
Direct Agglutination reactions use insoluble antigens (e.g RBC)
56
True or False: In Indirect/Passive agglutination reactions, a INSOLUBLE antigen of interest is attached to a SOLUBLE antigen
False
In an indirect/passive agglutination reactions, a SOLUBLE antigen of interest is attached to a INSOLUBLE antigen
57
Many proteins factors in the complement system are found in the ___ as inactive (zymogens)
serum
58
What molecules/structures are responsible for making the zymogens for the complement system?
Liver, monocytes, macrophages
59
What are the major functions of the complement system?
1) Opsonization "prepare food"
2) Recruit and activate phagocytic and inflammatory cells to site of complementation activation
(anaphylatoxins)
3) Margination
4) Regulate vascular tone
60
_____: small MW substance that induces degranulation of mast cells and release of histamine/other vasoactive substances
Anaphylatoxins
61
C3a, C4a and C5a components are referred to as ____
Anaphylatoxins
C5a (strongest), C3a, C4a (weakest)
62
C3b and C4b act as ____, thereby tagging microorganisms, dead cells, antigens, etc. for phagocytosis by macrophages and neutrophils — which possess complement receptors (!)
opsins
63
What two molecules regulate vascular tone?
C2 and C2 kinin
64
_____: A process in inflammation that allows leukocytes to adhere to endothelium of vessel walls in preparation for movement from vasculature to site of inflammation
Margination
65
True or False: Margination is associated with C5a
True
66
____: Movement of leukocytes through a gradient toward increasing concentrations of a substance
Chemotaxis
67
What are two chemoattractants for WBC's?
C5a and C3a
68
What is the ultimate goal of the Complement System?
Form the membrane attack
complex (MAC) which results in cell lysis.
69
What molecule removes Immune Complexes?
RBC's (via CR1) - they move to the RE system (liver and spleen) and undergo phagocytosis
70
Opsonization describes the _____and is
mediated by complement protein______.
A. Tagging of microorganisms - C3b
B. Tagging of microorganisms – C5a
C. Directional migration of leukocytes – C3b
D. Directional migration of leukocytes – C5a
E. Regulation of vascular tone – C3b
F. Regulation of vascular tone – C5a
A. Tagging of microorganisms - C3b
71
What are the three activation pathways?
1) Classical
2) Alternate
3) Lectin
72
All three activation pathways result in the formation of _____
C3 Convertase
73
True or False: The complementation pathways converge at a single terminal pathway
True
74
If not removed, IC’s (immune complexes) tend to aggregate, enlarge, and precipitate in basement membrane of small blood vessels in the kidney glomeruli, synovium, and skin
True
75
C3 convertase is an important amplification step in both the
___and ___complement pathways.
alternative ; classical
76
True or False: A single C3 convertase can activate hundreds
of C3 molecules
True
77
What is the order in which the C molecules (4) are activated in the Classical Activation Pathway?
C1, C4, C2, C3
78
How is the classical pathway activated?
1) Antigen-antibody complexes containing IgM or IgG
79
C1 binds to ___ portion of the antibody, leading to its activation
Fc
80
What is required for C1 activation?
Simultaneous binding to TWO molecules of Fc in close proximity (either 2 molecules of IgG in close proximity to one another or 1 molecule of IgM)
81
Once C4b accepts C2, what does activate C1 (C1’) do?
C1' cleaves C2 → C2a + C2b, → C4b2b Complex
82
In the classical activation pathway, what complex cleaves C3 into C3a and C3b?
C4b2b Complex
83
Once C4b2b Complex cleaves C3 into C3b and C3a, ___ binds to the membrane and ____ is formed
C3b ; C4b2b3b
84
What gives the classical activation pathway more control and allows for
regulation PRIOR to amplification of the pathway, to the point in which potent
inflammatory mediators are produced in abundance?
Weaker anaphylatoxins are generated first (C4a then C3a) and the more
potent one is generated last (C5a)
85
True or False: The Alternative Pathway functions in the presence of antibodies
False - the Alternative Pathway functions in the ABSENCE of antibodies
86
What activates the Alternative Pathway?
Anything that hydrolyses C3
* leukocyte proteases
* plasmin
* bacteria or bacterial products (LPS, bacterial cell wall components)
* aggregated IgA
* cobra venom factor
* Cellophane
* Water “Ticking over"
87
Activation of Alternative Pathway occurs via hydrolysis of ___
C3
88
What factor binds to C3b in the alternative pathway?
Factor B
89
Factor B is a substrate for Factor ___
D
90
What is the role of Factor D in the Alternative Activation Pathway?
Factor D cleaves B to form C3bBb (the alternative pathway C3 convertase)
91
The Alternative Pathway is also known as the _______
Properidin Pathway
92
True or False: There is a amplification loop of C3 cleavage in the properidin pathway
True
93
Which molecule of the alternative pathway is so unstable that it requires Factor P to stabilize it?
Properdin (Factor P) binds to C3bBb and stabilizes it
94
Under what conditions is there an explosive amplification of C3 cleavage in the Properidin Pathway?
When C3bBb-Properdin Complex binds and cleaves increasing amounts of C3
95
True or False: Binding and cleavage by C3bBb-Properdin Complex increases the amounts of bound C3b AND further stabilizes C3bnBb-Properdin?
True
96
C3bnBb-Properdin is also know as ______ in the Alternative Pathway, which allows for activation of terminal pathway
C5 convertase
97
What protein in the Mannose Binding Lectin pathway binds to TERMINAL mannose residues of proteins and polysaccharides that are only located on surface of bacteria?
Mannose Binding Lectin (MBL)
98
In the Manose Binding Lectin pathway, ___ is structurally homologous to C1 of classical pathway
Mannose Binding Lectin (MBL)
99
What is the effect of Mannose Binding Lectin binding to mannose residues on bacterial surface?
Enzymatically activates MBL for same substrate as C1’
100
Which pathway is responsible for formation of the membrane attack complex (MAC)?
Terminal Pathway
101
What does the membrane attack complex do?
Pokes holes into cell membranes
-Cell membrane damage
-Cell lysis
102
True or False: Once a stable C5 Convertase is formed by either activation pathway, they converge into a single terminal pathway
True
103
C4b2b3b (classical) or C3bnBb (alternate pathway) act to cleave what molecule?
C5
104
Once C5b is formed, C6-8 bind sequentially. Then, ___polymerizes and inserts itself into the cell membranes, forming a channel that allows ____
C9 ; osmotic lysis
105
C_-_ are terminal complement components and form the membrane attack complex (MAC)
5-9
106
What pathway does C1 Inhibitor (C1INH) inhibit?
Classical and Lectin
107
How does C1INH inhibit Classical Pathway?
Dissociation of C1r and C1s from C1q
108
True or False: C1INH limits the amount of time that C1’ is active in the alternative pathway
False -
C1INH limits the amount of time that C1’ is active in the classical pathway
109
Where are DAF or CD55 located?
Decay Accelerating Factor
- cell surface
110
What is the function of DAF or CD55?
Dissociates C4b2b
(classical C3 convertase)
and C3bBb
(alternative C3 convertase)
111
True or False: Activation of CD55 can results in loss of enzymatic pathway and inhibition of either that alternative or classical pathway
True
112
What pathway does Factor H inhibit?
Alternative pathway
113
Factor H can disassociate ____ complexes
C3bBb
114
Factor H competes with Factor __ for binding to C3b (surface bound)
Factor B
115
Following dissociation of C4b2b or C3bBb by DAF, ____ cleaves the structures, preventing them from functioning
Factor I
116
Serum Carboxypeptidase B is a _____ Inactivator
Anaphylatoxin
117
True or False: The only real difference between the Lectin pathway and the classical pathway is that
MBL is substituted for C1 complex during initiation
True
118
Which complement activation pathway(s) can
be activated by a bacterial infection?
A. Classical pathway
B. Lectin pathway
C. Alternative pathway
D. Classical and Lectin only
E. All three
E.
119
Serum Carboxypeptidase B causes proteolytic removal of terminal ___ residues and inactivates anaphylatoxins
arginine
120
Which molecule prevents insertion of MAC and cytolysis? How?
Vitronectin (S protein)
Binds to C5b67 complex
121
What molecule PREVENTS C9 polymerization? How?
CD59 - binds to C5b-8
122
Deficiency of C1, C4, C2, C3 or Factor I are associated with what conditions?
1) Deficiency in opsionization
2) Difficulty clearing IC's
3) Susceptible to infx by encapsulated bactera
123
Difficulty handling blood borne infections with Neisseria meningitidis (gram negative) is associated with what type deficiencies?
A. C1, C2, C3, C5 deficiency
B. C6, C6, C7, C8 deficiency
C. Factor H deficiency
D. Factor I deficiency
B. Deficiency of C5, C6, C7, or C8
124
______ is associated with stress/trauma provoked vasodilatation and edema
usually of the skin, extremities, or GI mucosa
Type I Hereditary Angioedema
125
What are individuals with Type I Hereditary Angioedema deficient in ?
C1 Esterase Inhibitor (C1INH)
126
Which of the answers below is Factor H deficiency associated with?
A. Increased susceptibility to many bacteria
B. Increased infection by encapsulated bacteria and N. meningitis
C. Lysis of RBC/endothelial cells and hemolytic-ureimc syndrome
C. Lysis of RBC/endothelial cells and hemolytic-ureimc syndrome
127
Properdin deficiency is associated with: _____
A. Increased infections by encapsulated bacteria and N. meningitis
B. Increased susceptibility to many bacteria
C. Lysis of RBC/endothelial cells and hemolytic-ureimc syndrome
A. Increased infections by encapsulated bacteria and N. meningitis
128
MBL deficiency increases the susceptibility to *MANY* common bacterial infections including
1) _____
2) ____
3) ____
1) Neisseria meningitides
2) Streptococcus pneumoniae
3) Staphylococcus
aureus
129
Which antibody is normally found on the surface of B cells, in association with IgM, where it acts as a receptor
True
130
Serum half life of IgG, IgA, IgM, IgD, and IgE?
IgG = 23 days
IgA = 5.5 days
IgM = 5 days
IgD = 2.8 days
IgE = 2.0 days
131
Which IgG largely activates complement and have high agglutination capacity?
IgM
132
What two Ig's have high neutralizing activity?
IgG and IgM
133
_____: The multi-molecular complex formed upon binding of antigen with its antibody
Immune complex
134
A serum sample is diluted 1:16 and still yields a positive response, but the next dilution higher yields a negative response. What is the titer?
16
135
In clinical serology tests tests, either the ___ or ___ must be known
antibody; antigen
136
_____: when different antigens/epitopes that are similar enough in structure, shape, charge can be bound by the same antibody
Cross Reactivity
137
What type of binding tests are: direct and indirect Immunofluorescence, flow cytometry, and ELISA/EIA?
Primary Binding Tests
138
Which test is best for determining titers?
A. ELISA
B. EIA
C. DFA
D. IFA
A. ELISA
139
_____: tests that allow Ag and Ab to combine and then measure amount of immune complex formed
Primary Binding Tests
140
Two examples of immunoassays?
1) Home pregnancy test
2) Rapid strep/rapid COVID
141
What molecule is a highly potent chemotactic factor for neutrophils?
C5a
142
What molecule is a highly potent chemotactic factor for neutrophils?
C5a
143
What molecule triggers formation of MAC?
A. C5b
B. C6a
C. C5a
A. C5b
144
True or False: Type I Hereditary Angioedema is associated with generation of bradykinin
True
145
What may cause the spontaneous attacks seen in Type I Hereditary Angioedema?
1) Activation of bradykinin
2) Activation of C1 by plasmin
3) Generation of C4a
146
What Factor competes with Factor B for binding to C3b and can dissociate C3bBb complex?
Factor H
147
Following dissociation of C4b2b or C3bBb by DAF, Factor ____ cleaves the structures, preventing function
Factor I
148
149
150
151
