Module 3 Flashcards
(107 cards)
1
Q
What is humoral immunity?
A
Immunity mediated by the humors, of body fluids
2
Q
After centrifuging blood to remove RBCs what is the remaining liquid?
A
Plasma
3
Q
What do you call plasma without the clotting agents?
A
Serum
4
Q
What are two other names for antibodies?
A
Immunoglobulins (Ig) and gamma globulins
5
Q
What is the structure of an antibody?
A
Two heavy chains and two light chains in the form of a Y
6
Q
What are the two types of antibody light chains?
A
Kappa and Lambda
7
Q
What connects the heavy chains of an amino acid as well as the light chains to the heavy chains?
A
Disulfide bridges
8
Q
Because the heavy chains and light chains are identical, antibodies are structurally ____
A
Symmetrical
9
Q
What is the variable region of an antibody?
A
The highly variable first 100 amino acids that make up the specificity characteristics of the antibody
10
Q
Where is the variable region located on an antibody?
A
At the amino terminus of the light and heavy chains, at the tips of the Y
11
Q
Where is the constant region of the amino acid?
A
The carboxy terminus, the Y except the tips
12
Q
What are the two functional domains of an antibody?
A
Fab and Fc
13
Q
What is the Fab (fragment antigen binding) functional domain of an antibody?
A
It is located at the split of the Y and accounts for the specificity of the single antigen binding site
14
Q
What is the Fc (fragment crystallizable) functional domain of the antibody?
A
It is located at the bottom of the two heavy chain constant regions or the stem of the Y and serves as effector function mediation instead of binding
15
Q
What is an epitope?
A
The sub-portion of antigen that binds to the Fab domain of an antibody
16
Q
What determines the strength of the affinity between an antibody and an antigen?
A
The sum total of its non-covalent bonds
17
Q
How many hyper variable regions are there in the antibody variable region?
A
Three
18
Q
What else is the hyper variable region of an antibody known as?
A
Complementarity Determining Regions (CDR1, CDR2 and CDR3)
19
Q
Where is the greatest amino acid variability in an antibody?
A
The hyper variable regions
20
Q
What are the five human isotypes?
A
IgA, IgD, IgE, IgG and IgM
21
Q
Where do isotypes differ from each other?
A
The heavy chain constant region (where the Y splits)
22
Q
How can you tell the difference between the four subtypes of IgG?
A
They differ in length at flexible hinge region of the heavy chains (where the Y splits)
23
Q
What is the most abundant isotype and predominates in the secondary response?
A
IgG
24
Q
Which isotype is secreted as a pentameter with 10 Ag binding sites and is most predominant in the primary response?
A
IgM
25
Which isotype is secreted as a diner with 4 Ag binding sites and is most predominant in bodily secretions?
IgA
26
How is passive immunity passed through breast milk?
IgA is readily available in breast milk, though with no memory B cells the immunity doesn’t last
27
What are the five antibody isotypes?
IgM, IgG, IgA, IgE and IgD
28
What is the defining feature of IgM?
It is the first Ab formed in the primary response and is a pentamer
29
What are the distinctive features of IgG?
It is the most abundant Ag in serum, has four types and is a major part of the secondary response
30
What are the defining features of IgA?
It is a dimer Ag that is present in external secretions including breast milk
31
What are the distinctive features of IgE?
They sensitize mast cells and basophils resulting in allergy symptoms and helminth protection
32
What are the distinctive features of IgD?
It is expressed on naive B cells and activity is rarely demonstrated
33
What accounts for the limitless antibody varieties that can by synthesized by an individual?
Gene rearrangement events that occur during B cell development in the bone marrow and T cell development in the thymus
34
Where are the genes that encode for the heavy and light chains of an antibody?
Across three separate chromosomes
35
Immunoglobulin locusts organized into coding cadets made up of what?
Multiple V, J and D regions
36
What are the three gene segments of the antibody heavy chain?
Variable (V) segment, Diversity (D) segment and Joining (J) segment
37
What are the two light chain antibody gene segments?
Variable (V) segment and Joining (J) segment
38
Where do Rag1 and Rag2 (recombination activator genes) bind for VDJ gene recombination?
The recombination signal sequence motifs (RSS) located where genes can be recombined
39
What do RAG1 and RAG2 do as a part of VDJ gene recombination?
They bring together the gene segments together to recombine and cleave gene at RSS motif
40
What is the process of P additions after the VDJ recombination?
Hairpin DNA loops created during recombination are opened and refilled by DNA repair enzymes
41
What is the process of N additions after VDJ recombination?
TdT enzyme (terminal deoxynucleotide transferase) adds random nucleotides to exposes chromosome ends
42
Which is the first isotype expressed by naive B cells?
IgM
43
What is the process by which a DNA rearrangement occurs between constant regions in exchange of Cmu coding region for constant regions of a different isotype?
Isotype switching
44
What is the antibody isotype found during primary response?
IgM
45
What is the antibody isotype primarily found in secondary response?
IgG
46
What is responsible for altering the affinity strength between an antibody and antigen?
Single point mutations of the somatic hypervariable region of immunoglobulin DNA
47
During clonal selection, which B cell receptors are selected?
Those with a higher Ag affinity
48
What is affinity maturation?
When secondary and later responses produce antibodies with increasing affinity
49
What are the four steps at occur during B cell development in the bone marrow?
1. V-region assembly from gene fragments
2. Generation of junction diversity
3. Assembly of transcriptional controlling elements
4. Transcription activation with coexpression of surface IgM and IgD
50
What are three changes that occur post activation to B cells in secondary lymph tissue?
1. Membrane Ig changes to secreted antibody
2. Somatic hypermutation
3. Isotype switch
51
What are the five effector functions of the different antibody isotypes?
1. Neutralization of pathogens
2. Opsonization
3. NK cell sensitization
4. Mast cell sensitization
5. Complement activation
52
What binds to viruses to prevent its attachment to a host cell receptor?
Fab (the arms of the antibody)
53
Which antibody is the most important neutralizer for the mucosal tract?
IgA
54
Which antibody is found in breast milk?
IgA
55
Which antibody isotype diffuses across the placenta for passive immunity during fetal development?
IgG
56
Which part of the antibody binds to bacterial pathogens blocking its ability to colonize?
Fab (the arms of the antibody)
57
How are secreted exotoxins neutralized?
Fab binds to toxins blocking its ability to cause cellular damage
58
Phagocytes (neutrophils and macrophages) have Fc receptors for which antibody isotypes?
IgG1 and IgG3
59
What happens during opsonization?
Phagocytes bind to Fc portion of antibodies that coat a pathogen for enhanced uptake
60
Which antibody isotypes trigger NK cells to attack?
IgG1 and IgG3 which coat the target cell such as a virus infected host cell or cancer cell
61
Which antibody isotype coat helminthic parasite activated eosinophils to secrete toxins that damage worms?
IgE
62
Which antibody isotype bind to Fc receptors on mast cells and basophils?
IgE
63
Which three antibody isotypes activate the complement cascade by the classical pathway?
IgM, IgA and IgG
64
What is the Western Blot test?
The process to identify protein/a set of proteins within a mixture
65
What are the four steps of a Western Blot test?
1. Proteins separated with electrophoresis through polyacrylamide denaturing gel
2. Proteins transferred onto filter paper and exposed to antibody that binds to protein of interest
3. Excess antibody washed off and secondary antibody added that is specific for the bound antibody
4. Secondary enzyme conjugated to an enzyme that reacts and makes a color to show protein location
66
What is the Enzyme Liked Immunosorbent Assay (ELISA) test?
A sensitive quantitative technique for detecting antigens or antibodies that can be used for diagnostics
67
What are the seven steps of the ELISA test?
1. Each of the 96 wells on the microtiter plate filled with a protein sample
2. Primary antibody added to each well
3. Antibody binds if antigen is present
4. Excess antibody removed
5. Secondary specific antibody added
6. Secondary antibody changes color
7. Amount of color measured by spectrophotometer
68
What does Immunoaffinity Chromatography accomplish?
It is a process that purifies a specific macromolecule
69
What are the four steps of immunoaffinity chromatography?
1. Antibody specific for macromolecule of interest sent through chromatography beads in a column
2. Mixture of macromolecules pass over the column
3. Macromolecules of interest bind to the antibody and the other pass along
4. Change in salt or pH of Washington buffer removes the bound macromolecules
70
What is the process of immunofluorescence microscopy?
Antibodies conjugated to a fluorescent molecule can be detected under a fluorescent microscope
71
What are the four steps of fluorescent activated cell sorting (FACS)?
1. Antibodies conjugated to a fluorescent molecule
2. Stream of fluid passes through flow cytometer nozzle that allows only one cell at a time
3. Laser activates fluorescent antibody
4. Detected by a computer
72
What is the difference between immunofluorescence microscopy and fluorescence activated cell sorting?
Both use fluorescent tagging, but only FACS allows for the cells to be separated and counted
73
What is the benefit of monoclonal antibodies (MAb) over polyclonal antibodies?
When antibodies are used as a research tool or therapeutic drug it is best to have a pure antibody
74
How are monoclonal antibodies produced?
Immunize mice with antigen of interest, causing an immune response. Remove the B cells and fuse with myeloma cells. Hybridomas can then be analyzed by flow cytometry and ELISA to identify antibodies
75
What is a hybridoma?
A normal B cell fused with a cancerous B cell (myeloma) which can grow indefinitely in culture
76
What is HAMA and how is it created?
Human anti-mouse antibody, it is created when the human immune system reacts against mouse antibodies
77
What three diagnoses are treated with humanized monoclonal antibodies?
Breast cancer, rheumatoid arthritis and MS
78
How are chimeric monoclonal antibodies made?
mRNA from mouse hybridomas modified using recombinant DNA techniques to replace antibody coding with human sequence.
The mouse V region (murine) is maintained
79
How are humanized monoclonal antibodies produced?
mRNA from mouse hybridomas modified with recombinant DNA technique to replace antibody protein coding with human sequence.
Only the hypervariable murine regions (CD1, CD2 and CD3) maintained and the rest wrapped with human sequences
80
What is required for a full humanized monoclonal antibody?
A knockout-transgenic mouse
81
What process of producing monoclonal antibodies does not require mice?
Fully humanized phage display
82
Antigens are made up of many antigenic determinants, also known as?
Epitopes
83
Bacterial cells have many different epitopes, which of which bind to?
Specific antibodies
84
An individual antibody is made against?
One epitope on a cell
85
Each antigen has ___ epitope(s)?
One
86
Each antigen has many epitopes, and a different antibody is formed against ____
Each epitope
87
Antibodies are?
Immune system-related proteins also known as immunoglobulins
88
The antigen binding site of immunoglobulin is formed from what?
Paired V chain region of a single heavy chain and single light chain
89
When IgG is cleaved with a protease that targets the hinge, what is generated?
Two Fab fragments and two Fc fragments
90
What is the part of the antibody that binds to an antigen?
The V domain
91
What contributes 50 lads to the molecular weight of IgG?
The heavy chain
92
What comprises the beta strands and loops not involved in antigen binding?
The framework region
93
Which is the most conserved region of the molecule with limited variation between antibodies?
The constant region
94
What is located within the V region and varied greatly between antibodies?
The hypervariable region
95
What pairs with the amino-terminal part of the heavy chain to form an antibody arm?
A light chain
96
Which epitope is formed as a result of 3D folding of a protein, and which would be destroyed if the protein denatures?
A conformational protein epitope
97
All epic exclusion ensures that B cells do what?
Express only one V, J and D segment during somatic recombination
98
Which IgG subclass is most efficient at activating complement?
IgG3, because it’s hinge is longest and makes its Fc region more accessible for C1 binding.
99
Which IgG subclass is least effective at complement activation?
IgG4 fils to activate complement because it’s Fc region binds poorly to C1
100
Which antibody plays a role in opsonization, complement activation, and is the most abundant?
IgA
101
Which antibody sensitizes basophils?
IgD
102
Which antibody sensitizes mast cells, basophils and is the least abundant?
IgE
103
Which antibody plays a role in opsonization and complement activation, as well as transports across the placenta, sensitizes masts cell, NK cells and is abundant?
IgG
104
Which antibody only plays a role in complement activation?
IgM
105
What are humanized monoclonal antibodies?
Human antibodies where the CDR loops have been replaced by mouse-derived CDRs of the desired specificity
106
Which IgG subclass cannot activate complement?
IgG4 can not activate complement because it’s Fc region binds poorly to C1.
107
Why can the immune system continue to make antibodies after treatment with anti-CD20 antibody rituximab?
Plasma cells do not express CD20 on their surface and cells protected by these cells continue as normal.
