CMB2004 (immunity) UPDATED ACTUAL
Exam Questions and CORRECT Answers
What must an effective immune response do? (4 things) - CORRECT ANSWER - Be able
to recognise and respond to invading pathogen
Not over-react to to benign or self
Be able to direct different effector mechanisms against different pathogens
Links innate and adaptive responses
What is adaptive immunity? (3 details) - CORRECT ANSWER - It is induced by exposure
to a PARTICULAR infection, it has a high degree of specificity.
It exhibits memory
What is the clonal selection theory? Why? - CORRECT ANSWER - It states that each
lymphocyte has membrane-bound immunoglobulin receptors specific for a particular antigen and
after the receptor is engaged, proliferation of the cell occurs such that a clone of antibody-
producing cells is produced.
This is because there's a low frequency of cells specific for any antigen, more receptors than
cells.
Describe the level of antibody production in the primary and secondary immune response? -
CORRECT ANSWER - When first exposed to antigen, low antibody production (innate
response, non specific)
Adaptive starts to with increased Ig production.
Decrease in Ig means the immune response has been successful.
,With a secondary infection the lag phase would be quicker, so more antibodies are produced
quickly.
Where's the BCR expressed? - CORRECT ANSWER - by B lymphocytes (The membrane
form of Ig), secreted when the B cell is activated)`
What does the BCR bind? - CORRECT ANSWER - Free antigen
Where's the TCR expressed? - CORRECT ANSWER - On T lymphocytes, membrane
form only
What does the TCR bind? - CORRECT ANSWER - Recognizes peptide fragments
(processed antigen)
bound to MHC
What's the immunoglobulin superfamily? - CORRECT ANSWER - a large group of cell
surface and soluble proteins that are involved in the recognition, binding, or adhesion processes
of cells. Including Antibodies T cell receptors, MHC molecules
What are the two main functions of antibodies? - CORRECT ANSWER - To activate
complement- for oposonisation, classical pathway activation and MAC
Activation of effector cells- Cells that express FcR (the receptor that binds to the FC region of
the antibody)
Describe the structure of an antibody - CORRECT ANSWER - Formed via 4 polypeptides
C terminus at the constant region, N terminus at the variable regions.
Has different domains, Hc identical as are Lc
,held by both covalent and non covalent bonds
What region of an antibody is the antigen binding site made up of? - CORRECT
ANSWER - The variable regions of one heavy and one light chain
What is the constant region of an antibody? - CORRECT ANSWER - The region which is
the same in any antibody. Responsible with interacting with molecules such as FcR and cells of
the innate system for antibody effector functions
What's the structure of a light chain of the antibody? - CORRECT ANSWER - It has a
lamda or kappa regions
What are Fc regions? - CORRECT ANSWER - They are Ch regions which interact with
effector cells via FcR and complement
What are the 5 classes of antibodies? - CORRECT ANSWER - IgM---- largest antibody,
first to appear, pentamer (10 binding sites)
IgA---- mucosal immunity, including tears and saliva
IgD--- coexpression with IgM, Secreted in blood serum
IgG---Most common, crosses placenta so protects the fetus, causes opsonisation
IgE--- immunity to helminths, least abundant, allergies
What are domains in an antibody? - CORRECT ANSWER - The domains are highly
conserved between bits of the immune system,
, The heavy chain has 4 or 5 whilst the light has 2
Composed of 2 beta sheets held via disulphide bridges
each 110 aa in length
What is the MHC? - CORRECT ANSWER - Major histocompatibility complex
A set of genes which encode cell surface molecules, bind peptide fragments and display then on
the surface for recognition.
How do antibodies and antigen interact? - CORRECT ANSWER - Via the binding site,
variable regions are specific to a given antibody..
possess hypervariable regions, variable regions within variable regions ( 3 in Hv and 3 in Lv)
HV1-3
6 hv loops make up the binding site
What are complementary determining regions? - CORRECT ANSWER - CDRs are the
same as hypervariable regions (CDR1-3)
Antigen binds to amino acids in CDRs (affected by the size and shape)
What are the two types of antigen recognition? - CORRECT ANSWER - Linear
(continuous) epitope: 3 single amino acids/ 3 regions of antigen , sequential
Non linear/discontinuous epitope: conformational
What is an epitope? - CORRECT ANSWER - The region of an antigen that the antibody
recognises
Exam Questions and CORRECT Answers
What must an effective immune response do? (4 things) - CORRECT ANSWER - Be able
to recognise and respond to invading pathogen
Not over-react to to benign or self
Be able to direct different effector mechanisms against different pathogens
Links innate and adaptive responses
What is adaptive immunity? (3 details) - CORRECT ANSWER - It is induced by exposure
to a PARTICULAR infection, it has a high degree of specificity.
It exhibits memory
What is the clonal selection theory? Why? - CORRECT ANSWER - It states that each
lymphocyte has membrane-bound immunoglobulin receptors specific for a particular antigen and
after the receptor is engaged, proliferation of the cell occurs such that a clone of antibody-
producing cells is produced.
This is because there's a low frequency of cells specific for any antigen, more receptors than
cells.
Describe the level of antibody production in the primary and secondary immune response? -
CORRECT ANSWER - When first exposed to antigen, low antibody production (innate
response, non specific)
Adaptive starts to with increased Ig production.
Decrease in Ig means the immune response has been successful.
,With a secondary infection the lag phase would be quicker, so more antibodies are produced
quickly.
Where's the BCR expressed? - CORRECT ANSWER - by B lymphocytes (The membrane
form of Ig), secreted when the B cell is activated)`
What does the BCR bind? - CORRECT ANSWER - Free antigen
Where's the TCR expressed? - CORRECT ANSWER - On T lymphocytes, membrane
form only
What does the TCR bind? - CORRECT ANSWER - Recognizes peptide fragments
(processed antigen)
bound to MHC
What's the immunoglobulin superfamily? - CORRECT ANSWER - a large group of cell
surface and soluble proteins that are involved in the recognition, binding, or adhesion processes
of cells. Including Antibodies T cell receptors, MHC molecules
What are the two main functions of antibodies? - CORRECT ANSWER - To activate
complement- for oposonisation, classical pathway activation and MAC
Activation of effector cells- Cells that express FcR (the receptor that binds to the FC region of
the antibody)
Describe the structure of an antibody - CORRECT ANSWER - Formed via 4 polypeptides
C terminus at the constant region, N terminus at the variable regions.
Has different domains, Hc identical as are Lc
,held by both covalent and non covalent bonds
What region of an antibody is the antigen binding site made up of? - CORRECT
ANSWER - The variable regions of one heavy and one light chain
What is the constant region of an antibody? - CORRECT ANSWER - The region which is
the same in any antibody. Responsible with interacting with molecules such as FcR and cells of
the innate system for antibody effector functions
What's the structure of a light chain of the antibody? - CORRECT ANSWER - It has a
lamda or kappa regions
What are Fc regions? - CORRECT ANSWER - They are Ch regions which interact with
effector cells via FcR and complement
What are the 5 classes of antibodies? - CORRECT ANSWER - IgM---- largest antibody,
first to appear, pentamer (10 binding sites)
IgA---- mucosal immunity, including tears and saliva
IgD--- coexpression with IgM, Secreted in blood serum
IgG---Most common, crosses placenta so protects the fetus, causes opsonisation
IgE--- immunity to helminths, least abundant, allergies
What are domains in an antibody? - CORRECT ANSWER - The domains are highly
conserved between bits of the immune system,
, The heavy chain has 4 or 5 whilst the light has 2
Composed of 2 beta sheets held via disulphide bridges
each 110 aa in length
What is the MHC? - CORRECT ANSWER - Major histocompatibility complex
A set of genes which encode cell surface molecules, bind peptide fragments and display then on
the surface for recognition.
How do antibodies and antigen interact? - CORRECT ANSWER - Via the binding site,
variable regions are specific to a given antibody..
possess hypervariable regions, variable regions within variable regions ( 3 in Hv and 3 in Lv)
HV1-3
6 hv loops make up the binding site
What are complementary determining regions? - CORRECT ANSWER - CDRs are the
same as hypervariable regions (CDR1-3)
Antigen binds to amino acids in CDRs (affected by the size and shape)
What are the two types of antigen recognition? - CORRECT ANSWER - Linear
(continuous) epitope: 3 single amino acids/ 3 regions of antigen , sequential
Non linear/discontinuous epitope: conformational
What is an epitope? - CORRECT ANSWER - The region of an antigen that the antibody
recognises
