Practice Questions
Immunology- Exam 2
1. The class-specific (isotype) determinants (or regions) of immunoglobulins are associated with:
A. L chains
B. J chains
C. disulfide bonds
D. H chains
E. variable regions
2. An immunoglobulin molecule contains
A. two identical light chains
B. variable and constant regions on each chain present
C. two identical heavy chains
D. one heavy chain
E. one light chain
3. (5 points). Draw a typical antibody (immunoglobulin) molecule. Label the variable and constant
regions, and the light and heavy chains. Indicate which region determines the antibody’s isotype (class)
and which region determines it’s antigenic specificity.
I can’t draw in word. Make sure you have 2 heavy chains, 2 light chains and then mark off the
variable and constant regions. The heavy chain constant confers isotype, the combination of light
chain variable and heavy chain variable confers specificity.
4).
a). True or false. All immunoglobulin molecules on the surface of a given B cell have the same
specificity?
b). True or false. All immunoglobulin molecules on the surface of a naïve matureB cell are the
same isotype?
5). The ability of a single B cell to express both IgM and IgD receptor molecules on its surface at the same
time is made possible by:
A. allelic exclusion
B. isotype switching
C. simultaneous recognition of two distinct antigens
D. selective RNA splicing
E. use of genes from both parental chromosomes
6). The specificity of an immunoglobulin is associated with
F. D regions
G. J lambda chains
H. antigenic determinant regions
I. H chains
J. variable regions
7. If you could analyze, at the molecular level, a plasma cell making IgA antibody, you would find all of
the following except
A. a DNA sequence for V,D, J genes translocated near the C DNA exon.
B. mRNA specific for either kappa or lambda light chains
C. mRNA specific for J chains
D. mRNA specific for  chains
E. a DNA sequence coding for the T-cell receptor for antigen
8. Some factors which lead to antibody diversity are:
A. Multiple V genes in the germ line
B. RNA splicing
C. VJ and VDJ rearrangements
D. Somatic Cell mutations
E. random assortment of H and L chains
9. Which of the following concerning Ig expression on a B cell is correct;
A. The light chains of the IgM and IgD have identical amino acid sequences
B. The constant parts of the heavy chains of the IgM and IgD have different amino acid
sequences
C. The IgM and IgD have different antigenic specificities
D. IF the B cell is triggered by antigen it will proliferate and differentiate into IgM and IgD
producing plasma cells
E. The IgM on the surface will have either kappa light chains or lambda light chains, but
not both.
10. Which of the following are true concerning isotype switching.
A. IgM and IgD can be replaced with another antibody isotype
B. IgD can be turned on to make large quantities of serum antibodies
C. After class switching you can reverse the process and make IgM
D. Cytokines are responsible for determining which isotype will be made
E. There are switch genes in front of every distinct isotype except IgD
11. Genes that make up the heavy chain are
A. V region genes
B. D region genes
C. J region genes
D. kappa genes
E. C region genes
12. The antigen specificity of a particular B cell
A. is induced by interaction with antigen
B. is determined only by the L-chain sequence
C. is determined by H + L chain variable region sequences
D. changes after isotype switching
E. is determined by the heavy-chain constant region
13. Which of the following are true concerning the ontogeny (maturation) of B lymphocytes?
a. Pre-B cells form cytoplasmic  chains
b. surrogate light chains are formed during the late pre-B stage
c. Mature B cells express IgM only
d. stimulation of immature B cells causes proliferation and differentiation
e. Mature B cells have CD3 molecules associated with the membrane bound immunoglobulins
14. What happens if an immature B cell encounters non-self soluble antigen in the bone marrow:
___________it goes anergic_______________________________
15. What happens if an immature B cell encounters non-self surface antigen in the bone marrow?
_____receptor editing of the light chain or apoptosis__________________________________________
16. Antibody isotype switching occurs when B cells get the proper ___cytokine______________ signal.
17. Immature B lymphocytes
A. produce only  chains
B. are progenitors of T as well as B lymphocytes
C. express both IgM and IgD on their surface
D. are at a stage of development where contact with antigen may lead to unresponsiveness
E. must go through the thymus to mature
18. Which of the following statements regarding B cell hybridoma is false?
A. They are immortal cell lines that produce antibodies of a single specificity
B. They are derived from B cells that are first cloned and grown in culture for short periods
C. They contain a large nucleus formed by the fusion of two nuclei
D. They can be used to manufacture diagnostic or therapeutic monoclonal antibodies
E. They are derived by fusing B cells with malignant plasma cells that are unable to secrete
immunoglobulin.
19. (5 points) Describe the procedure for making monoclonal antibodies.
Look this up. Procedure for making hybridomas, then monoclonals.
20. (10 points) Describe in detail B cell ontogeny (maturation process). Make sure to indicate where in
the body this is occuring and all the steps that occur during the maturation process.
This should include all stages including pro B, pre B, immature and mature and should tell me what
is going on during each time (which genes are rearranging and which genes have stopped
rearranging because of viable protein product).
21. The DNA for an H chain in a B cell making IgG2 antibody for diphtheria toxoid has the following
structures: 5’-V17D5J2 C2--C4--C--C2—3’ . How many individual rearrangements were required to go
from the embryonic DNA to this B-cell DNA? 3 (2 rearrangements for the VDJ, and one more for the
iostype switching).
22. Which molecule can be found on all nucleated cells?
a. CD3
b. 2 microglobulin
c. CD40
d. CD45
e. MHC class II molecules
23. Antigens processed by the endogenous pathway are displayed on ____MHC I____________________
.
24. Which of the following are true concerning the T cell receptor (TcR)
a. belongs to the immunoglobulin superfamily
b. composed of a heterodimer,  or  chains
c. can sometimes express both chains
d. 95% of the T cells express  chains
e. is always associated with the CD3 complex
25. Which is true of CD3
a. is found on all T cells
b. is found only on CD4 T cells
c. is always associated with the TcR
d. is necessary for signal transduction
e. functions to trap antigen on the T cell surface
26. CD8 T cells recognize antigen in the context of which MHC complex __MHC I_______________ .
27. Which of the following are true of exogenous pathway?
a. most antigens are taken into the antigen presenting cell through phagocytosis
b. it is associated with MHC class II
c. antigens are processed in the cytoplasm of the cell
d. it is associated with 2 microglobulin
e. an invariant chain blocks the binding groove of the MHC complex until it moves into an
endosomal vacuole
28. In the endogenous pathway, antigen slips into the grooves of the MHC molecule in what organelle?
_____endoplasmic reticulum______________________ .
29. In humans, the MHC is known as ___Human Leukocyte Antigen_____________________________
30. Which of the following is true about the genetics of HLA
A. HLA class I and class II are on separate chromosomes
B. HLA class I and class II genes are separated by non-HLA genes
C. all HLA class I genes have known functions
D. DP, DQ and DR genes are part of the class II HLA
E. Some HLA haplotypes are more susceptible to genetic disorders
31. You have just caught a cold virus from your roommate. This virus attaches and enters mucosal
epithelial cells before it starts to replicate.
(4 points) Describe in detail how the antigen will be processed in the epithelial cell.
Describe the endogenous pathway. Virus gets into cell, gets processed in the cytoplasm, carried to ER
through TAP, associated with MHC class I and exported to the cell surface. (I expect more details than
this)
(1 point) Which class of MHC will the processed antigen be displayed? ___I______________
(1 point) Which T Cell population will respond to this antigen? ____CD8___________________
(2 points) How will this T Cell population respond (i.e. what will it do to rid the body of this
foreign invader)?
Direct lysis of virally infected cells.
(2 points) Will there be any B Cell involvement with this pathogen? If so, briefly describe how B
Cells will get involved and what the end result will be (in general terms).
B cells can get involved while the virus is briefly extracellular. It will process antigen, present it to
CD4 T Cells and then be activated to produce antibody.
32. Questions refer to the diagrams (19.5 points):
VH(n=50)
DH(n=20)
JH(n=6)
A. 5’ //==V1== V2== V3==Vn===//=D1=D2==Dn=//== J1= J2= =J6====3=1=1=2=4==2=// 3’
B.
5’//==V1==V2==V3=V4D2J3=J4=J5=J6====3=1=1=2=4==2=//3’
5’//-V4D2J3-J4-J5-J6—--—3’
C.
V4D2J3
D.
E.
DNA
V4D2J3
NH2
COOH
VH
RNA
C
NH2
RNA
COOH
VH
Protein
C
1. What is the germline DNA in row A coding for? ___heavy chain IG_____________________
2. What genes were excised after rearrangement? V5-V50, D1, D3-D20, J1-J2______________________
3. In the primary transcript (before splicing), do you still have the gene for J 4? _yes_________
4. After rearrangement has occurred, do you still have the gene V1 in your new DNA? __yes___________
5. How many rearrangements were necessary to achieve the product on line B? __2________
6. In your new DNA (after rearrangement), do you still have the gene for 4? yes
33. Which of the following are true of positive selection of T cells?
a. Only T cells that bind very tightly to B Cells will be selected
b. Selection occurs in the cortex of the thymus
c. Only T cells with moderate affinities for self-MHC are allowed to develop
d. T cells that are positively selected undergo apoptosis
e. after positive selection T cells leave the thymus in search of antigen
34. Which of the following are true of negative selection of T cells?
a. Negative selection occurs in the bone marrow
b. It results in the elimination of T cells reactive with self components other than MHC
c. those that do not get negatively selected undergo apoptosis
d. T cells undergoing negative selection express only CD4 or CD8 molecules
e. Most of your millions of thymocytes survive both positive and negative selection
35. (10 points) Describe T cell differentiation and education in the thymus. Be sure to describe both 
and  T cell populations for differentiation, then only describe  T cells for T cell education.
The great race PLUS positive and negative selection. I’m going to let you do this one from the book.
36. T Cells mature and learn to discriminate between self and non-self antigens in the
_______thymus______________ (what organ?).
37. You are an M.D. who just finished a biopsy of a swollen lymph node. You visualize the cell
population using monoclonal antibodies conjugated with fluorescin isothiocyanate and discover an
abundance of CD4+ T Cells.
a.(1 point) What were the monoclonal antibodies specific for that allowed you to determine this?
____CD4_________
b. (1 point) Where are the immature thymocytes being made? ____bone marrow________________
c. (1 point) Where do the thymocytes go to mature and be educated? _thymus_______________________
d. (2 points) What are the two possibilities of TCR that can be made (two different TCR heterodimers)?
_alpha beta________ or _gamma delta___________
f.
(5 points) Describe the process by which the T Cell Receptor (TCR) is made? again this is the
great race between alpha beta and gamma delta T cells, starting with the rearrangement of
beta, gamma and delta genes.
f. (1 point) Which of the TCR heterodimers comprise 95% of the T Cell population? _alpha
beta________
g. (1 point) Which of the TCR heterodimers undergo positive and negative selection? ____alpha
beta____
h. (2 points) Briefly describe positive selection.
This is where double positive thymocytes test their TCR on thymic epithelial cells to see if they
recognize self MHC/self antigen with moderate to high affinity. If they recognize self MHC they
move on to negative selection, otherwise they rearrange their alpha gene or go through apoptosis.
i. (2 points) Briefly describe negative selection. Thymocytes that have regonized self MHC test to see
if they recognize self antigen with high affinity as foreign on thymic epithelial cells, macrophages or
dendritic cells. Those that bind too tightly are destroyed through apoptosis.
j. (1 point)When a mature T Cell is ready to leave the thymus, what cell surface receptors are they
expressing? _____CD4,____________________ or ____________CD8_______________ . (and CD3)
DON’T FORGET ABOUT MHC GENETICS. DIDN’T REALLY COVER THAT ON THIS PRACTICE
EXAM, SORRY.