B Cells Flashcards
(162 cards)
1
Q
Name for all proteins which structurally resemble antibodies
A
Immunoglobulin
2
Q
Proteins made by lymphocytes and plasma cells that specifically react with antigens
A
Antibodies
3
Q
Type of antigen that causes an immune response
A
Immunogen
4
Q
Any compound that elicits an immune response
A
Antigen
5
Q
Do antigens that are proteins and polysaccharides induce a strong or weak immune response?
A
Strong
6
Q
Do antigens that are lipids and nucleic acids induce a strong or weak immune response?
A
Weak
7
Q
Chemical structure of an antigen that is directly recognized
A
Epitope
8
Q
Does an antigen with different epitopes get recognizes more slowly or quickly than an antigen with repeated single epitope?
A
More rapidly (allows multiple different targets for recognition
9
Q
Antibody chains
A
2 identical heavy and light chains; both contain variable and constant regions
10
Q
Antigens bind to this location on antibody
A
Fragment antigen-binding (FAb) region (variable region)
11
Q
Constant region of antibody that tells the host how to handle the Ag:Ab complex
For interaction with host
A
Fragment crystallizable (Fc) region (constant region)
12
Q
Class of immunoglobulins that exists as a dimer in mucosal immunity
A
IgA
13
Q
Class of immunoglobulins that has trace amounts in the serum, is a monomer, and functions in naive B cell antigen receptor
A
IgD
14
Q
Class of immunoglobulins that has small amounts in serum and is involved in immediate hypersensitivity (mast cell activation)
A
IgE
15
Q
Class of immunoglobulins that has 4 different types, has high levels in serum and a long half-life.
Involved in defense against microbes in all tissues (neutralization, opsonization, complement, Ab-dependent cellular cytotoxicity), neonatal immunity
A
IgG
16
Q
Class of immunoglobulins that is present in the serum, part of naive B cell antigen receptor (monomeric form), defense against microbes (complement, neutralization), and can have a pentameric structure
A
IgM
17
Q
Molecule that links secreted IgM to form a pentamer
A
J chain
18
Q
Function of the J chain
A
Links secreted IgM to form a pentamer
19
Q
Does IgM have high or low avidity?
A
High due to pentamer structure
20
Q
Does IgM have high or low affinity?
A
Low
21
Q
B cells are produced here
A
Bone marrow
22
Q
The association of lymphoid progenitor cells with bone marrow stromal cells is mediated by these types of molecule
A
Cellular adhesion molecules (specifically the integrin VLA-4 and adhesion molecule VCAM-1)
23
Q
Expressed on B cells and binds to the membrane-bound stem cell factor (a growth factor)
A
Kit
24
Q
Kit is expressed on these cells
A
B cells
25
Production of this cytokine by bone marrow stromal cells stimulates B cell growth and proliferation
IL-7
26
IL-7 stimulates this
Stimulates B cell growth and proliferation
27
Is the heavy or light chain rearranged first in B cell rearrangement?
Heavy chain
28
Order of genes rearranged in B cell heavy chain
D to J, then V to DJ
29
Order of genes rearranged in B cell light chain
V to J
30
Number of constant genes on the heavy chain that define the antibody isotype that is being produced by the cell
9
31
Default constant genes for all B cells
Cμ (IgM) and Cδ (IgD)
32
B cells express these immunoglobulins at cell surface during development
IgM and IgD
33
Process of germline rearrangement that ensures gene segments are joined in the correct orientation
12/23 rule
Each V, D, or J segment is flanked by recombination signal sequences with either 12 or 23 base pair segments
34
The 12/23 rule ensures this
Ensures gene segments are joined in the correct orientation during lymphocyte germline rearrangement
35
Sequences which flank each V, D, or J segment and exist as nonamer and heptamer separated by either a 12 or 23 base pair segment
Recombination signal sequences (RSS)
36
Molecules which bind to the 12 and 23 base pair spacers of recombination signal sequences, bringing two heptamer sequences into close proximity through formation of a hairpin that contains the DNA segments that are being removed (V, D, or J)
Recombinase-activating genes (RAG-1 and RAG-2)
37
Recombinase-activating genes (RAG-1 and RAG-2) are involved in this process
Germline rearrangement; bind RSSs and aid in removal of sequences between V/D/J segments
38
Most abundant antibody in the blood
IgG
39
Enzyme that joins chromosomal DNA together to form the coding joint after VDJ rearrangement and removal of RSSs
Contributes to the diversity of Ab repertoire during the formation of the coding joint by adding N-nucleotides
Terminal deoxynucleotidal transferase (TdT)
40
Palindromic nucleotides, but they are not complementary to each other and cannot join together
P-nucleotides
41
Antibody that passes through the placenta
IgG
42
Antibody found in milk by lactation
IgA
43
Are rearrangements random?
Yes; occur throughout life
44
What makes up the pre-B cell receptor after heavy chain rearrangement?
Rearranged heavy chain, Surrogate light chain, and Iga and IgB (disulfide-linked signaling molecules)
45
Surrogate light chain is a required component of this
Pre-B cell receptor
46
Describes the strength of binding at a single site
Affinity
47
Describes the strength associated with binding multiple sites
Avidity
48
Process of encoding Ig genes from a single chromosome per cell, instead of both
Makes homogenous BCRs with high-avidity binding
Allelic exlcusion
49
These 2 immunoglobulins are co-expressed at the cell surface of mature, naive B cells by alternative splicing
IgM and IgD
50
Terminal deoxynucleotidal transferase (TdT) is involved in this process
Germline rearrangement 12/23 rule; joins chromosomal DNA together to form coding joint between V/D/J segments
Contributes to Ab diversity
51
If an immature B cell reacts with self antigen, it undergoes receptor editing via rearrangement of this locus
Light chain
52
Process where elimination of self reactive B cells occurs before they leave the bone marrow
Central tolerance
53
Process where elimination of self reactive B cells occurs after they leave the bone marrow
Peripheral tolerance (Anergy)
54
Chemokine that interacts with its receptor (CCR7) on B cells to attract B cells to the high endothelial venules and into lymph nodes
CCL21
55
Receptor on B cells for CCL21
CCR7
56
CCL21 interacts with its receptor CCR7, which is on these cells
B cells
57
Function of CCL21
Attracts B cells to high endothelial venules for movement into lymph nodes
58
Two TNF-alpha family members that drive the maturation of immature B cells
B cell activating factor (BAFF) and Lymphotoxin (LT)
59
TNF-alpha family member that is produced by follicular dendritic cells (FDCs) and binds it receptor on B cells to promote survival and maturation of the B cell
B cell activating factor (BAFF)
60
B cell activating factor (BAFF) is produced by these cells
Follicular dendritic cells
61
TNF-alpha family member that is produced by B cells and binds its receptor on FDCs to preserve integrity of the FDC network
Lymphotoxin (LT)
62
Lymphotoxin is produced by these cells
B cells
63
Cross-linking of antigen induces signaling within the B cells that is mediated by these signaling components of the BCR (Ig alpha and beta)
Immunoreceptor tyrosine-based activation motif (ITAM)
64
Signaling components of the BCR
Ig alpha and beta
65
Ig alpha and beta are apart of this
B cell receptor
66
3 proteins that make up the B cell co-receptor
CR2 (aka CD21), CD19, and CD81
67
CR2, CD19, and CD81 form this
B cell co-receptor; required for costimulation (cross-linking of the BCR alone is typically not sufficient)
68
Protein that recognizes either iC3b or C3d, and stimulates signaling through CD19
Complement receptor (CR2; also known as CD21)
69
Protein that acts as the signaling molecule for the B cell co-receptor
CD19
70
CR2 (aka CD21) recognizes either of these 2 proteins and stimulates signaling through CD19
iC3b or C3d
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CR2 (aka CD21) recognizes either iC3b or C3d and stimulates signaling through this
CD19
72
3 transcription factors produced after cross-linking and tyrosine phosphorylation events of B cell
NFAT, NF-kB, AP1
73
This antibody is secreted in the early phase of humoral immune response
IgM
74
B cells undergo affinity maturation (somatic hypermutation) and isotype switching in this location after antigen recognition
Germinal center of lymph node
75
After T cell recognizes antigen via peptide:MHC II complex on B cells, it expresses this on its surface, which binds to its counterpart on B cells and provides a second signal for B cell activation, leading to division and differentiation
CD40L
76
CD40L is expressed on these cells
Activated T cells
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Function of CD40L binding to CD40
Provides second signal for B cell activation
78
Antibody serum levels that increase first in an immune response
IgM
79
Process that selects for high affinity B cells
Somatic hypermutation
80
Enzyme made only by proliferating B cells
Deaminates cytosine residues within the single-stranded DNA into uracil, and DNA repair mechanisms randomly convert the U to any one of the 4 bases found in DNA
Activation-induced cytidine deaminase (AID)
81
Activation-induced cytidine deaminase (AID) is involved in this process
Somatic hypermutation and isotype switching in B cells
82
Somatic hypermutation occurs in these genes of B cells
Variable genes
83
Process by which a B cell changes the constant region that is expressed in its germline
Isotype switching
84
Isotype switching involves changes to these genes in B cells
Constant regions
85
Enzyme that removes the uracil generated by AID in isotype switching of B cells, leading to recombination
Uracil-DNA-glycosylase (UNG)
86
Uracil-DNA-glycosylase (UNG) is involved in this process
Isotype switching in B cells
87
Two T cell effectors that induce B cell isotype switching to IgE
IL-4 and IL-13
88
IL-4 and IL-13 promote B cell isotype switching to this Ig
IgE
89
Cytokines produced in mucosal tissues (TGF-B, BAFF) promote B cell isotype switching to this Ig
IgA
90
Cells that maintain antigen in the germinal center reaction
Follicular dendritic cells
91
Secretion of this by helper Tfh cells induces centrocytes to differentiate into plasma cells
IL-10
92
Secretion of IL-10 by helper Tfh cells induces centrocytes to differentiate this type of cell
Plasma cell
93
Secretion of this by helper Tfh cells induces centrocytes to differentiate into memory B cells
IL-4
94
Secretion of IL-4 by helper Tfh cells induces centrocytes to differentiate into this type of cell
Memory B cell
95
After B cells produce antibody, they can bind these receptors on follicular dendritic cells and hold non-complement epitopes in place
Fc receptors
96
After B cells produce antibody, they can bind Fc receptors on this type of cell and hold non-complement epitopes in place
Follicular dendritic cell
97
Antibody isotype most abundant in the secondary immune response
IgG
98
Type of B cells in spleen and other lymphoid organs that recognize protein antigen
Isotype-switched, long lived plasma cells
Follicular B cells
99
Type of B cells in spleen and other lymphoid organs that recognize lipids and polysacchardies
Mainly IgM, short-lived plasma cells
Marginal zone B cells
100
Type of B cells that supply lots of IgM
Marginal zone B cells
101
Marginal zone B cells supply lots of this
IgM
102
Type of B cells in mucosal tissues and peritoneal cavity that recognize lipids and polysaccharides
Mainly IgM, short-lived plasma cells
Characterized by expressing CD5 (normally T cell marker)
B-1 cells
103
B-1 cells are characterized by expressing this
CD5 (normally a T cell marker)
104
CD5 expression is characteristic of this type of B cell
B-1 cell
105
Type of T-independent antigens that can activate B cells by relying on complement components and TLR recognition of microbial products
TI-1 antigens (ex: LPS)
106
Type of T-independent antigens that activate B cells by extensively cross-linking the BCR and its co-receptor due to repetitive expression of identical epitopes on the surface of the pathogen
TI-2 antigens
107
B-1 cells typically respond to this type of antigen
TI-2 antigens
108
Only antibody type that can be produced without T cell help due to lack of interaction in germinal centers and no isotype switching
IgM
109
Type of B cells that respond to TI-2 antigens
B-1 cells
110
3 major antibodies that circulate throughout the body via the bloodstream
IgM, monomeric IgA and IgG
111
2 major antibodies in extracellular fluid
Monomeric IgA and IgG
112
Type of antibody that coats mucosal surfaces
Dimeric IgA
113
Type of antibody that associated with mast cells in the connective tissue beneath epithelial surfaces, particularly the skin, respiratory tract, and GI tract
IgE
114
Passive transfer of this antibody from mother to fetus occurs across the placenta via the FcRn
IgG
115
Passive transfer of IgG from mother to fetus occurs across the placenta via this
FcRn
116
Function of FcRn
Passive transfer of IgG across placenta
117
Antibody present in breast milk
Dimeric IgA
118
Receptor that transports dimeric IgA across mucosal surfaces
Binds to mucins and holds IgA in the mucus layer
Protects the IgA from degradation by enzymes present at mucosal sites
pIgR
119
People with an IgA immunodeficiency transport this antibody to mucosal surfaces via the pIgR
IgM
120
pIgR binds to dimeric IgA via this to transport it across epithelial cells at mucosal surfaces
J chain
121
Purpose of the J chain of dimeric IgA
pIgR binds to dimeric IgA via the J chain to transport it across epithelial cells at mucosal surfaces
122
Purpose of pIgR
Transports dimeric IgA across epithelial surfaces at mucosal surfaces
123
Antibody types involved in neutralization
All 4 IgG, IgA
124
Antibody isotypes involved in opsonization
IgG1 > IgG3
125
Antibody isotypes involved in sensitization for killing by NK cells
IgG1 and IgG3
126
Antibody isotypes involved in sensitization of mast cells and basophils
IgE
127
Antibody isotypes involved in activation of complement system
IgM, IgG3, IgG1
128
Antibody isotypes involved in diffusion into extravascular sites
All IgG, monomeric IgA
129
Antibody interaction with pathogen is via this region
Fab (variable) region
130
Antibody interaction with host is via this region
Fc (constant) region
131
Antibodies whose _______ regions do not exhibit high affinity interaction with their receptors play a role in protecting the host by neutralizing the pathogen so that it cannot interact with the host cell
Fc regions
132
Antibodies that have bound the surface of a pathogen, or ones that have bound soluble multivalent antigens, can activate the classical pathway of complement through interaction with this
C1q
133
Erythrocytes help to prevent immune complex deposition in the kidney glomeruli by expressing this, which recognizes immune complexes bound to C1q
CR1
134
Receptors expressed by host cells that allow for induction of an active process associated with removal of a pathogen from an infected host
Fc receptors
135
High affinity receptor that recognizes human IgG1 and IgG3
FcyRI
136
FcyRI is a high affinity Fc receptor that recognizes these
IgG1 and IgG3
137
FcyRI binding to the Fc portion of antibody occurs via this part of the receptor
Extracellular alpha chain
Signaling then occurs through a gamma chain that uses an ITAM
138
Signaling through FcyRI occurs through this, which utilizes this
Gamma chain; utilizes an ITAM
139
Activation of Fc receptors requires this
Cross-linking
140
Fc receptor expressed on NK cells
Involved in antibody-dependent cell-mediated cytotoxicity (ADCC)
FcyRIII
141
FcyRIII is expressed on these cells
NK cells
142
High affinity Fc receptor for IgE
Important for defenses against parasitic worms
FceRI
143
FceRI, the high affinity Fc receptor for IgE, is expressed on these cells
Mast cells
144
This response is important for defenses against parasitic worms
Fc receptor contributions to clearance: Mast cell degranulation (FceRI, IgE)
145
NK cell cytotoxic granules contain these 2 compounds
Perforin and granzymes
146
Fc receptor that when cross-linked in the presence of excess antibody, sends a negative signal through ITIM to the B cell to stop producing antibody
FcyRIIB
147
When cross-linked, FcyRIIB sends a negative signal to the B cell through this
ITIM
148
FcyRI is involved in this process
Phagocytosis
149
FcyRI is expressed on these cells
Macrophages and neutrophils
150
Is FcyRI high or low affinity?
High affinity; binds IgG1 and IgG3
151
Is FcyRIIB high or low affinity?
Low affinity
152
FcyRIIB is involved in this process
Feedback inhibition of B cells; attenuation of inflammation
153
Is FcyRIIIA high or low affinity?
Low affinity
154
FcyRIIIA is involved in this process
Ab-dependent cellular cytotoxicity
155
Is FceRI high or low affinity?
High affinity; binds IgE
156
FceRI is involved in this process
Activation (degranulation) of mast cells and basophils
157
Fc receptor involved in phagocytosis
FcyRI
158
Fc receptor involved in feedback inhibition of B cells
FcyRIIB
159
Fc receptor involved in Ab-dependent cellular cytotoxicity
FcyRIIIA
160
Fc receptor involved in activation (degranulation) of mast cells and basophils
FceRI
161
The secretory component is involved in this
pIgR transport of IgA across mucosal epithelium
Secretory component of the pIgR is cleaved and released along with the IgA
162
Portion of the pIgR that binds to mucins and holds IgA in the mucus layer and protects IgA from degradation by enzymes present at mucosal sites
Secretory component
