Quiz 5 - German - B Cells - Antibodies Flashcards
B cells produce what?
Antibodies
T/F - B cells target one antigen epitope.
TRUE
Plasma cells are what and secrete what?
Fully differentiated form of B cell
Secretes antibodies
Small lymphocyte produces what?
Production of antibodies (B cells) or cytotoxic and helper fxs (T cells)
T/F - B cells produce an antibody targeted against a single, unique antigen.
TRUE
Tell me more about B cells.
Affect extracellular pathogens
Infinite target diversity
Low probability of reaching maturation
Undergo colonial selection and expansion
Improve targeting following activation
Persist for years
There are 6 phases to B cell maturation. What are the first 3 phases that occur in the bone marrow?
I - Repertoire assembly - Generation of diverse and clonally expressed B-cell receptors in the bone marrow
II - Negative selection - Alteration, elimination, or inactivation of B cell receptors that bind to components of the human body
III - Positive selection - Promotion of a fraction of immature B cells to become mature B cells in the secondary lymphoid tissues
What are the 3 phases of B cell maturation that occurs in the periphery?
IV - Search for Infection - Recirculation of mature B cells b/t lymph, blood, and secondary lymphoid tissues
V - Finding Infection - Activation and local expansion of B cells by pathogen-derived antigens in secondary lymphoid tissues
VI - Attacking infection - Differentiation to antibody-secreting plasma cells and memory B cells in secondary lymphoid tissue
T/F - Antibodies are targeted effector proteins that target a single epitope.
TRUE
T/F - Antibodies are also called immunoglobulins.
TRUE
What is an epitope?
An exposed, small region of an antibody
T/F - An antigen can have multiple epitopes.
TRUE
What is neutralization?
Antibodies binding a toxin and neutralizing the threat
T/F - Antibodies are basically targeted effector proteins.
TRUE
What are the antibody classes?
M - Mew
A - Alpha
D - Delta
G - Gamma
E - Epsilon
What determines antibody class?
ISOTYPE
The ______ chain has a proportionally small variable region, while the ________ chain has a proportionally large variable region.
Heavy
Light
*Both bind antigen
What are the 2 isotopes of the light chain?
Kappa
Lambda
Which antibodies are multimeric?
IgM
IgA
IgM function?
Neutralization
Activate complement
Transport across epithelium
IgD function?
Sensitization of basophils
IgE function?
Sensitization of mast cells
Sensitization of basophils
IgG functions?
Neutralization
Opsonization
Sensitization for killing by NK cells
Sensitization of mast cells
Activation of complement
*T-port across placenta
Extravascular diffusion
IgA functions?
Neutralization
Opsonization
Activation of complement
**T-port across epithelium
Extravascular diffusion
What portion of antibody binds antigen?
Technically, both, but the FAB is what binds the antigen on the light chain
What is an antigen?
Molecule recognized by a B or T cell
What is an epitope?
Region of an antigen bound by an antibody or MHC/TCR
T/F - Antibody structure facilitates fx.
TRUE
Tell me the B cell development timeline and include heavy, then light chain designation.
Bone Marrow
Stem cell - germline, germline Early pro-B - germline, germline Late pro-B - DJ, germline Large pre-B - VDJ, germline Small pre-B - VDJ, germline Immature B cell - VDJ, VJ
Lymphoid organs/circulation
Immature B cell (IgM, no IgD) Immature B cell (High IgM, low IgD) Mature, naive B cell (Low IgM, High IgD) Antigen activated B lymphoblast Antibody-secreting plasma cell Memory cell
T/F - Antibody genes are assembled from fragmented segments.
What does this mean?
TRUE
Gives enormous diversity of antigen binding
_________ recombination creates antibody coding sequence. This is tied to specific B cell developmental stages.
Somatic
What does the RAG complex do?
Randomly pairs gene segments
RAG 1 and 2 complexes bind what?
RSSs
Recombination signal sequences
Gene segments are randomly paired to create coding sequences
What are the three orders associated with RAG?
V-D-J —> V-DJ (All heavy)
V-DJ —> VDJ (All heavy)
V-J —> VJ (All light)
What is junctional diversity created?
RECOMBINATION
What can mutations during recombination do?
Throw off the sequence and antibody won’t be created properly
Frameshift/stop codon could lead to improper production of antibody
What is TdT?
Terminal deoxynucleotidyl transferase
What are the only two antibody types that are produced simultaneously?
IgM
IgD
How can a single B cell express all antibody isotopes?
Class switching
The Fc region is conserved, by the light chains can be switched
Class switching is permanent
IgM and IgD are the first ones expressed
What do Fc receptors bind?
Conserved regions
Tell me the three things that happen when activation occurs.
Activation changes B cell immunoglobulin fate
1 - Antibody secretion
2 - Somatic hypermutation
3 - Class switching
—IgM/IgD —> IgG/IgA/IgE
What does somatic hypermutation do?
Rapidly increases antibody affinity
What are three main sources of antibody diversity?
Genetic recombination - Random
Junctional diversity - Random nucleotides put in b/t the two
Somatic hypermutation - Isotype switching
Somatic hypermutation targets what?
The rearranged gene segments encoding the variable region
What does polyclonal mean?
Multiple antibodies targeted against the same antigen
What does monoclonal mean?
Single antibody target against a single antigen
What are the 4 types of therapeutic monoclonal antibody?
Mouse
Chimeric
Humanized
Human
Antibodies are important ________ and __________ tools.
Diagnostic
Therapeutic
Tell me how antibodies are diagnostic.
Pathogen ID
Protein quantification
Cellular ID
Tell me how antibodies are therapeutic.
Targeted killing
Chemical delivery
Immunomodulatory
