TUTORIAL 3
Multiple Choices
For each of the questions below select the one best answer.
1.
Which class of antibodies would you expect to find in the circulation of a fetus?
A.
B.
C.
D.
E.
2.
The following properties render a substance immunogenic: Although IgM is said to be
of low affinity, the avidity of IgM can be high because it
A.
B.
C.
D.
E.
3.
IgA
IgG
IgM
IgM and IgG
IgM, IgG and IgA
is a large molecule
is produced in large quantities
is found on naïve B cells
forms a dimer
forms a pentamer
An individual who has a genetic defect in the J chain gene will not be able to synthesize
which class of antibodies?
A.
B.
C.
D.
E.
IgA and IgG
IgM
IgM and IgA
IgG
IgM and IgG
4.
A naive B cell expresses both IgM and IgD on the cell surface. These two
immunoglobulin molecules _____________.
A. are identical except for their VH regions
B. are identical except for their CH regions
C. have different VH and VL regions
D. have identical CH and VH regions
E. have identical heavy chains but different light chains
5.
The class-specific antigenic determinants (epitopes) of immunoglobulins are associated
with
A.
B.
C.
D.
E.
L chains.
J chains.
Disulfide bonds.
H chains.
variable regions.
6.
The idiotype of an antibody molecule is determined by the amino acid sequence of the
A.
B.
C.
D.
E.
Constant region of the L chain.
Variable region of the L chain.
Constant region of the H chain.
Constant regions of the H and L chains.
Variable regions of the H and L chains.
7.
Injection into rabbits of a preparation of pooled human IgG could stimulate production
of
A. Anti-γ heavy-chain antibody.
B. Anti-κ chain antibody.
C. Anti-λ chain antibody.
D. Anti-Fc antibody.
E. All are correct.
8.
A polyclonal antiserum raised against pooled human IgA will react with
A.
B.
C.
D.
E.
human IgM.
κ light chains.
human IgG.
J chain.
All are correct.
9.
Papain digestion of an IgG preparation of antibody specific for the antigen hen egg
albumin (HEA)
A. will lose its antigen specificity.
B. precipitate with HEA.
C. lose all interchain disulfide bonds.
D. produce two Fab molecules and one Fc fragment.
E. None of the above.
10.
The following properties of human IgG are true except:
A. It can pass through the placenta.
B. It can be cleaved by pepsin and yet remain divalent.
C. Its half-life is approximately 23 days.
D. It induces the formation of leukocytes.
E. It participates in the activation of complement.
11.
The relative level of specific IgM antibodies can be of diagnostic significance because
A. IgM is easier to detect than the other isotypes.
B. Viral infection often results in very high IgM responses.
C. IgM antibodies are more often protective against reinfections than are the other
isotypes.
D. Relatively high levels of IgM often correlate with a first recent exposure to the
inducing agent.
12.
The primary and secondary antibody responses differ in
A.
B.
C.
D.
E.
The predominant isotype generated.
The number of lymphocytes responding to antigen.
The speed at which antibodies appear in the serum.
The biologic functions manifested by the Ig isotypes produced.
All of the above.
Structure Questions
1.
When a person is diagnosed with dengue fever, it is important to determine whether it
is a primary or secondary infection. One way is to determine the ratio of IgM to IgG.
Explain with the aid of a diagram. What would a high IgG to IgM ratio indicate?
2.
Rituximab is a chimeric mouse-human monoclonal antibody (mab), with mouse
variable regions and human constant regions. It binds to CD20, which are found on B
cells. Rituximab has been used successfully to treat Burkitt's lymphoma, a B cell cancer.
Describe ONE way in which Rituximab binding could lead to the killing of lymphoma
cells.
Explain why the mechanism may not work if a mouse anti-CD20 mab is used instead of
a chimeric antibody.
3.
Explain why monoclonal antibodies are better for diagnostic kits rather than polyclonal
antibodies.