BIOL3003 WEEK 6-13 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
What are antibodies?
Glycoproteins secreted by B cells
What is the difference between polyclonal and monoclonal antibodies? (Week 6
lec 16)
Polyclonal:
- animal immunised
- serum collected
- antibody is affinity purified
- antibody is heterogeneous, limited supply, batch specific
Monoclonal:
- animal immunised
- spleen cells harvested and fused with myeloma cells
- single cell clones screened for reactivity against antigen
- unlimited supply of antibody with defined specificity
What are antibodies used for?
- Cell isolation and identification (magnetic bead isolation, flow cytometry, panning)
- Cell biology (ELISA, immunoblotting, immunoprecipitation,
immunocytochemistry/immunofluorescence)
,- In vivo studies (antibody-blocking experiments,
immunohistochemistry/immunofluorescence)
- Diagnostics
What are the main types of approaches taken in immunology? (Week 6 lec 16 for
details)
(A and B ususally go together to get the full picture)
More cell specific:
1.A. Depletion and adoptive transfer of immune cells in vivo - big picture idea of what
the cells do
1.B. Isolation and functional studies of a particular cell type in vitro - breaks things down
to a simpler system so that mechanistic studies are possible
Gene specific:
2.A. Blocking gene/protein function: antibody or gene KO - compare wild-type vs KO
mice for biological response
2.B. Enhancing gene/protein function: transgenic over-expression or recombinant
protein administration
Which antibody isotype can cross the placenta?
IgG
What are the 5 general antibody functions?
,1. Neutralisation
2. Opsonisation
3. Compliment activation (classical pathway)
4. ADCC (Antibody-dependent cell-mediated cytotoxicity, NK cells recognise Fc regions
and kill cells via apoptosis)
5. Triggering of mast cells (cross-linking of IgE), basophils and activated eosinophils
How do B cells undergo isotype switching?
Signal 1:
- Thymus dependent antigen binding to BCR
Signal 2:
- Thymus-independent antigen: intrinsic second signal (e.g. via TLRs)
OR
- T helper cell cytokines (e.g. IL-4, IFN-gamma) and CD40L
What are the steps and timing of GOD and isotype switching?
- Generation of BCR in bone marrow
- Negative selection in bone marrow
- Migration of B cells to peripheral lymphoid organs and activation
- Antibody secretion and memory cells in bone marrow and lymphoid tissue - isotype
switching
- Plasma blast and plasma cell - alternative splicing yields both membrane and secreted
Ig
What are the steps involved in isotype switching?
, - AID converts C to U in s.s DNA (not sure how it gets to ss DNA....)
- UNG removes base of U, leaves only the sugar part
- APE1 removes sugar to leave nick in DNA
- Clusters of nicks are made
- DSBR machinery excises sequence and joins 2 switch regions
What is hyper-IgM syndrome and what can cause it?
- Lack of isotype switching resulting in the production of IgM but not much else
Can result from:
- Deficiency in Th cell function: CD40L deficiency (and possibly other signalling
cytokines)
- Deficiency in B cell machinery: CD40, NEMO, AID
What isotypes are the different Th cells biased to generating?
While response is the same in humans, the specific isotype class in this answer is
mouse specific.
Th1 bias (through IFN-gamma): IgG2a - resistance to intracellular pathogens:
macrophage activation through ITAM domain in specific IgG2a Fc receptor- also more
tissue damage
Th2 bias (through IL4/5): IgG1, IgE, IgA - susceptibility to intracellular pathogens:
macrophage deactivation through ITIM domain in specific IgG1 Fc receptor, IL-4
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
What are antibodies?
Glycoproteins secreted by B cells
What is the difference between polyclonal and monoclonal antibodies? (Week 6
lec 16)
Polyclonal:
- animal immunised
- serum collected
- antibody is affinity purified
- antibody is heterogeneous, limited supply, batch specific
Monoclonal:
- animal immunised
- spleen cells harvested and fused with myeloma cells
- single cell clones screened for reactivity against antigen
- unlimited supply of antibody with defined specificity
What are antibodies used for?
- Cell isolation and identification (magnetic bead isolation, flow cytometry, panning)
- Cell biology (ELISA, immunoblotting, immunoprecipitation,
immunocytochemistry/immunofluorescence)
,- In vivo studies (antibody-blocking experiments,
immunohistochemistry/immunofluorescence)
- Diagnostics
What are the main types of approaches taken in immunology? (Week 6 lec 16 for
details)
(A and B ususally go together to get the full picture)
More cell specific:
1.A. Depletion and adoptive transfer of immune cells in vivo - big picture idea of what
the cells do
1.B. Isolation and functional studies of a particular cell type in vitro - breaks things down
to a simpler system so that mechanistic studies are possible
Gene specific:
2.A. Blocking gene/protein function: antibody or gene KO - compare wild-type vs KO
mice for biological response
2.B. Enhancing gene/protein function: transgenic over-expression or recombinant
protein administration
Which antibody isotype can cross the placenta?
IgG
What are the 5 general antibody functions?
,1. Neutralisation
2. Opsonisation
3. Compliment activation (classical pathway)
4. ADCC (Antibody-dependent cell-mediated cytotoxicity, NK cells recognise Fc regions
and kill cells via apoptosis)
5. Triggering of mast cells (cross-linking of IgE), basophils and activated eosinophils
How do B cells undergo isotype switching?
Signal 1:
- Thymus dependent antigen binding to BCR
Signal 2:
- Thymus-independent antigen: intrinsic second signal (e.g. via TLRs)
OR
- T helper cell cytokines (e.g. IL-4, IFN-gamma) and CD40L
What are the steps and timing of GOD and isotype switching?
- Generation of BCR in bone marrow
- Negative selection in bone marrow
- Migration of B cells to peripheral lymphoid organs and activation
- Antibody secretion and memory cells in bone marrow and lymphoid tissue - isotype
switching
- Plasma blast and plasma cell - alternative splicing yields both membrane and secreted
Ig
What are the steps involved in isotype switching?
, - AID converts C to U in s.s DNA (not sure how it gets to ss DNA....)
- UNG removes base of U, leaves only the sugar part
- APE1 removes sugar to leave nick in DNA
- Clusters of nicks are made
- DSBR machinery excises sequence and joins 2 switch regions
What is hyper-IgM syndrome and what can cause it?
- Lack of isotype switching resulting in the production of IgM but not much else
Can result from:
- Deficiency in Th cell function: CD40L deficiency (and possibly other signalling
cytokines)
- Deficiency in B cell machinery: CD40, NEMO, AID
What isotypes are the different Th cells biased to generating?
While response is the same in humans, the specific isotype class in this answer is
mouse specific.
Th1 bias (through IFN-gamma): IgG2a - resistance to intracellular pathogens:
macrophage activation through ITAM domain in specific IgG2a Fc receptor- also more
tissue damage
Th2 bias (through IL4/5): IgG1, IgE, IgA - susceptibility to intracellular pathogens:
macrophage deactivation through ITIM domain in specific IgG1 Fc receptor, IL-4
