Immunology Exam 2
What is the y-axis label of immunohistochemistry?
% stained tissue
How long does B-cell maturation from a HSC to a mature B cell take?
1-2 weeks
Identify the antigen receptor produced by B lymphocytes:
B cell receptor (BCR)
What two cell types do follicles contain?
B cells and follicular dendritic cells
Which of the following constitutes the critical survival for B cells in the secondary lymphoid tissue cortex?
BAFF
What are the 3 signals required to activate a naive, mature B cell?
BCR-antigen interaction, costimulatory signal, and a cytokine signal from a TH cell or follicular dendritic cell (FDC)
Deficiency in RAG1 and/or RAG2 can affect the proper development of which of the following cell types, resulting in decreased numbers of circulating cells of those types?
Both B and T cells
What is an example of a costimulatory signal?
CD40 on B cell interacts with CD40L on TH cell
Activated TH cells signal to B cells to initiate their activation program via which of the following?
CD40L on the T cell to CD40 on the B cell
What is the difference between CD64 and CD32?
CD64 is activating, so it will stimulate clearance of pathogen through processes such as phagocytosis. CD32 is inhibiting, so it prevents the appropriate immune cells from responding to the pathogen.
___________ is performed on liquid samples.
ELISA
________ uses antibodies to detect specific molecules.
ELISA and IHC
Which Fc-receptor is responsible for triggering the release of histamine, proteases, and other inflammatory signals from IgE?
FCE receptor
If an antibody was attached to a virus, this region would be specifically binding to the virus:
Fab
This region of an antibody contain the variable regions of the heavy and light chains:
Fab
If an opsonizing antibody was attached to a virus, this region could bind to receptors on a phagocytic cell and then signal for the virus/antibody complex to be phagocytosed:
Fc
This region of an antibody contains the constant region of the heavy chain:
Fc
This region of an antibody determines the isotype of the antibody:
Fc
This region of an antibody is always different between IgG and IgE:
Fc
___________ leads to the production of IgG3 and IgG2a
IFN-gamma
__________ is performed on tissue biopsies.
IHC
What is one difference between IHC and ELISA?
IHC uses tissue as a sample while ELISA uses supernatant
_________ leads to the production of IgG1 and IgE
IL-4
_________ leads to the production of IgA only
IL-5
Which type of antibody is MOST effective against the largest variety of pathogens?
IgG
Which class of antibodies is the FIRST to be produced during the primary immune response?
IgM
Why is IgM the class of antibody able to form large polymers?
IgM has low affinity and benefits from having a large number of binding sites
Define central tolerance
Immature self-reactive T or B cell clones that recognize self-Ag are eliminated
V-DJ recombination occurs during which phase of a B cell's development?
Pro-B cell
How does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in Pre-B cells?
RAG1 and RAG2 are downregulated, and TdT activity is lost so that no additional heavy-chain rearrangements may take place
What introduces single-strand break between V(D)J coding sequence and heptamer RSS?
RAG1/2
What does the RAG1/2 enzyme complex bind to at the start of the V(D)J recombination process?
RSS
Identify the antigen receptor produced by T lymphocytes:
T cell receptor (TCR)
Of the cells listed below, which one represents the MOST developed B cell? T1 B cells T2 B cells Pro-B cell Pre-pro-B cell Pre-B cell
T2 B cells
With regard to the type of B-cell response generated, protein antigens typically provoke which of the following responses? TI-2 TD TI-1 All None
TD
___________ leads to the production of IgA and IgG2b
TGF-B
Identify the enzyme that randomly adds nucleotides to the chromosome during VDJ recombination.
TdT
Fc-receptor molecules tend to have short cytoplasmic tails. How does this influence signaling events within the Fc-receptor cell?
The Fc-receptor is dependent upon a coreceptor (e.g., ITAM or ITIM) that will trigger signaling events within the cell.
In heavy chain genes, what are the gene segments?
V, D, J
Identify the gene segment needed to make a heavy chain gene:
V, D, J, C
Identify the gene segments needed to make a light chain gene:
V, J, C
How is BALF collected?
a bronchoscope is inserted though the mouth/nose into the lung. fluid is inserted into the lung and is then collected for examination
Define allelic exclusion.
a mechanism that has evolved to make sure that a B cell only transcribes and expresses 1 heavy chain allele and 1 light chain allele
What is BAFF?
a survival factor that binds the BAFF-R to allow T2 B cells to mature into B cells
What type of immunity takes longer, each cell has one type of receptor (clonal), and has high specificity?
adaptive
What are the major processes that occur in secondary lymphoid organs?
adaptive immune cells become activated by interactions with antigen and immune response is initiated
Central tolerance is lost in a patient when:
an autoreactive B cell is able to leave the bone marrow, so it does not undergo receptor editing, clonal deletion, or anergy
What would happen is a patient has low CR1 levels?
an immune complex cannot be removed from the blood by transport with an RBC, so the kidney will be more damaged trying to remove all the waste itself
What is the effector molecule of humoral immunity?
antibodies
Virally infected host cells are tagged with antigen-antibody complexes. These complexes recruit NK cells that trigger apoptosis in the infected host cell. This is an example of:
antibody-dependent cell-mediated cytotoxicity
____________ is part of a pathogen that is recognized by BCRs and TCRs?
antigen
BALF would most likely be collected if you were studying:
asthma
Which of the following would NOT be included when examining a person's exposome? being born with a p53 mutation working in a coal mine drinking lead contaminated water living at a high altitude
being born with a p53 mutation
EMSA would test the ability of RAG to do what?
bind to RSS segment on the DNA
Define autoreactive.
binds to self-antigens and results in immunity against self cells
B lymphocytes are made in the:
bone marrow
What are the two primary lymphoid organs?
bone marrow and thymus
Lysis of a pathogen by MAC formation is an example of:
complement fixation
Hematopoiesis produces what types of cells?
erythroid, lymphoid, and myeloid lineage cells
What is the beneficial agent in the research studied in class?
exposure to DHA (fish/fish oil)
What is the damaging agent in the research studied in class?
exposure to silica
A ___________ is located in the cortex of lymph nodes and in the white pulp of the spleen. It contains B cells and follicular dendritic cells.
follicle
Where are T2 B cells located?
follicle
What is the germ-line theory?
genetic information for each individual antibody is encoded separately in the genome
What are the two theoretical models of antibody generation?
germ-line theory and the somatic hypermutation theory
a ___________________________ is the site in a follicle where B cells are concentrated to undergo proliferation and differentiation to form a colony of B cells with high affinity for the same antigen.
germinal center
What major processes occur in the bone marrow?
hematopoiesis and maturation of B cells
What is the benefit of allelic exclusion?
if B cells were to express more than one type of receptor on each cell, there would be a higher likelihood of producing a BCR that would recognize self-antigen
DHA (promotes/inhibits) inflammation that occurs during autoimmunity.
inhibits
What type of immunity is the first line of defense, happens quickly, has many different receptors on one innate cell (non-clonal), and has low specificity?
innate
Describe a Pre-BCR
it has a completed heavy chain expressed on the cell surface along with a surrogate light chain (while the light chain is being rearranged)
Describe a BCR
it has a heavy chain (mu chain) expressed on the cell surface with a complete light chain (kappa or lambda)
Describe a BCR-antigen interaction.
it is the internalization/processing of antigen to it can be presented as a peptide on MHC II, which is recognized by TH cell
One location of ectopic lymphoid tissue could be __________.
kidney (not a lymphoid organ)
What major processes occur in the thymus?
maturation of T cells
The research described in the article by Melissa Bates et al., was performed using:
mice that spontaneously develop Lupus-like symptoms over time
Antigen receptors are (less/more) specific than TLRs.
more
What are the 5 mechanisms to generate antibody diversity?
multiple gene segments (different combinations of V, D, and J), heavy chain/light chain combinational diversity (which heavy chains are paired with which light chains), p-nucleotide addition randomness, exonuclease trimming leading to the loss of nucleotides, and n-nucleotide addition randomness
_____ describes the action of antibodies whereby antibodies bind to a pathogen and prevent the pathogen from interacting with cell receptors.
neutralization
_______________ describes the action of antibodies whereby antibodies bind to a pathogen and prevent the pathogen from interacting with cell receptors.
neutralization
What is the y-axis label of ELISA?
ng/ml
_____________ describes the recruitment of phagocytic cells by the Fab portion of an antibody.
opsonization
________________ is a B cell that has matured and differentiated. It produces and secretes antibodies.
plasma cell
What is the somatic hypermutation theory?
recombination of existing gene segments occurs only in B cells so it is not passed onto offspring
What is a productive rearrangement?
resulting regions are "inside the reading frame" and was successful producing a functional chain
What is non-productive rearrangement?
results in formation of "out of frame" joines
One location of eutopic lymphoid tissue is ______________.
spleen
Where are T1 B cells located?
spleen
Where do developing B cells complete their maturation through the T1 and T2 stages?
spleen
What or the secondary lymphoid organs?
spleen, lymph nodes, MALT, and other diffuse and loosely organized areas (ex: tonsils)
Define exposome.
sum of lifetime environmental factors of an individual
What did Dreyer and Bennett propose?
that heavy and light chains were encoded separately and recombination occurs
What would happen without the cytokine signal from TH or FDC cells?
the B cell would not be activated to produce different isotypes via CSR
Central tolerance is maintained in a patient when:
the BCR is autoreactive, and it undergoes receptor editing, clonal deletion, or anergy
What is the problem with germ-line theory?
the genome is simply not extensive enough to encode for the amount of BCRs that exist in our bodies to fight infection
An example of ectopic lymphoid tissue would be follicles located in:
the kidneys
Define receptor editing.
the light chain is further rearranged when the combination is found to be autoreactive; RAG is turned back on to make another cleavage in the DNA
Where is red pulp and white pulp located?
the spleen
Are there more antigen receptors or TLRs?
there are more antigen receptors, because they have a higher specificity
Why does rearrangement happen up to two attempts?
there are only 2 alleles for each locus (2 for heavy chain, 2 for kappa light chain, 2 for lambda light chain)
What is the role of the BCR in T1 B cells?
they aid in negative selection through being presented with self-antigens and tested for high affinity for self
What are M cells and where are the located?
they are located between the gut lumen and the GALT, and they mediate transcytosis of particles from the lumen to the GALT
What is one similarity between immunohistochemistry (IHC) and ELISA?
they both use antibodies
Most people are exposed to DHA when:
they eat fish
What is the purpose of costimulatory signals? What happens without them?
they help stimulate B cell proliferation. without this signal, the B cell would not be activated.
What is the role of the BCR in T2 B cells?
they provide stimulatory survival signals that promote up-regulation of the BAFF-receptor so that the B cell can bind BAFF
IgA is typically found as a dimer in high levels of secretions such as milk, tears, and saliva. What is the primary function of IgA in secretions?
to neutralize toxins and pathogens
The first immunoglobulin isotype produced during the course of a primary immune response contains which of the following heavy chains:
u
What must the BCR do during B cell development in order for the B cell to leave the bone marrow?
undergo negative selection, where auto-reactive BCRs are deleted or undergo receptor editing
Where are B cells located?
white pulp in B cell follicles