2/23/17 TEST #2 GERMAN B cells: Antibodies and Diversity Flashcards
What is the main job of B cells?
-Produce antibodies
What do the antibodies produced affect?
-Extracellular pathogens
What do B cells target?
-One antigen epitope
T/F B Cells have infinite target diversity
True
What is a plasma cell?
-Fully differentiated form of B cell that secretes antibodies
T/F B cells do not undergo clonal selection and expansion
False
-They do undergo
Once B cells have been activated what happens to the targeting?
-It improves
What do the first three phases of B cell production take place?
-Bone marrow
What occurs in the first phase of B cell production?
-Generation of diverse and clonally expressed B-cell receptors
What occurs in Phase 2 of B cell production?
-Elimination or inactivation of B-cell receptors that bind to components of the human body (- selection)
What is Phase 3 of B cell production?
-Promotion of a fraction of immature B cells to become mature B cells in the secondary lymphoid tissues (+ selection)
T/F Antibodies are glycoproteins
True
What are four effector functions of produced antibodies?
- Receptors
- Neutralization
- Opsonization
- Signaling
What are two cells that produced antibodies have receptor functions for?
- B cells
- Granulocytes
What are the three sources of antigen diversity?
- Genetic recombination
- Junctional diversity
- Somatic hypermutation
Are the antigen binding sites the variable or constant region?
-Variable region
What two chains do you find on an antibody?
- Heavy Chain
- Light Chain
T/F Isotype determines antibody class
True
What are the five isotypes of the Heavy chain of the antibody?
- IgG
- IgA
- IgM
- IgE
- IgD
What chain on the antibody binds the antigen?
-Heavy chain and light chain
What are the two isotypes of the light chain antibodies?
- Kappa
- Lambda
What region of the antibody does complement interact with?
-Conservative region
When you cleave antibodies with proteases what are the products?
- 2 Fab fragment
- 1 Fc fragment
What two antibody classes interact with a J chain?
- IgM
- IgA
When the IgM interacts with the J chain what multimeric complex forms?
-Pentameric IgM
When the IgA interacts with the Jchain what multimeric complex forms?
-Dimeric IgA
What are IgD really good at doing?
-Sensitization of basophils
What antibodies go out into the tissues in a response?
-IgG
What two antibodies are good at activating complement?
- IgM
- IgG
What does IgG do well?
- Neutralization
- Opsonization
- Sensitization for killing by NK cells
- Diffusion into extravascular sites
- Activation of complement
What does IgA do well?
- Neutralization
- Transport across epithelium
What does IgE do well?
-Sensitization of mast cells
What is an antigen?
-A molecule recognized by a B cell or T cell
What is an epitope?
-The region of an antigen bound by an antibody or MHC/TCR
T/F Antibody structure facilitates function
True
In the bone marrow what causes changes in antibody structure?
-Gene rearrangement
In secondary lymphoid organs and circulation what causes changes in antibody structure?
- Somatic hypermutation
- Isotype Switching
What is always formed during Somatic Hypermutation and Isotype Switching?
- IgD
- IgM
What are antibody genes assembled from?
-Fragmented Segments
What are the four segments of the heavy chain?
- Variable
- Diversity
- Joining
- Constant
What is the first two regions selected for antibody diversity?
- Junctional region
- Variable region
The RAG complex randomly pairs what?
Gene segments
What grabs and combines the different portions of the genome for antibodies?
- RAG 1
- RAG 2
What is the order to create the Heavy chain?
-Vh-Dh-Jh—-> Vh - DJh—->VDJh
What is the order to create the Light chain?
-VL-JL—>VJL
When is junctional diversity created?
-Recombination
How many antigen binding regions are there per B cell?
one
T/F B cells can express all ab isotypes
True
When you do an Isotype switch is it permanent?
-Yes with one exception when you have both the IgD and IgM expressed
What are the two isotypes that are expressed first?
- IgM (1st)
- IgD (2nd)
What does the Fc receptor bind?
-Conserved regions
What antibodies acts as the B cell receptors?
- IgA
- IgB
Genetic recombination variability for B cells is caused by what?
-Splicing
What is Junctional diversity?
-Add random nucleotides between these genetic section made during recombination
What is it called when multiple antibodies targeted against the same antigen?
-Polyclonal
What is called when a single antibody targeted against a single antigen?
-Monoclonal
What are three diagnostic tools that antibodies provide?
- Pathogen Identification
- Protein quantification
- Cellular identification
What are three therapeutic tools that antibodies provide?
- Targeted killing
- Chemical delivery
- Immunomodulatory
