Download Practice Exam 2 with answers

MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
1. Therapeutic antibodies can influence the progression of autoimmune disease in a number of
ways. Which of these ways is described below?
a. By blocking a natural ligand that influences the immune response
b. By blocking a natural receptor that influences the immune response
c. By causing the downregulation of a receptor that influences the immune response
d. By depleting a cell population that can influence the immune response
e. All of the above (A-D) are possible ways that antibodies can influence autoimmune
disease
2. A random mutation has occurred in one of the offspring of a C57BL/6 mating in the mouse colony
in your lab. This mutant mouse has lymph nodes that are swollen to 100 times their normal size due
to lymphocyte accumulation in the lymph node tissue. From the list below, identify a gene
encoding a mutant protein that could be responsible for this phenotype?
a. CTLA4
b. MHC II Beta Chain
c. Fas Ligand
d. CD45RA
e. B7
3. What role does a MAMP (microbial associated molecular pattern) receptor play?
a. It activates negative selection in the thymus.
b. It activates cells with pattern recognition receptors during the innate immune
response.
c. It directly activates the classical pathway of the complement cascade.
d. It blocks protein kinase activation.
e. It regulates quorum sensing in bacteria.
4. Upon T cell stimulation and activation, different sets of genes are activated at different time
points. We divide these responses into categories including immediate-, early-, and late-activated
genes. Which gene from the list below would be an “immediate” gene in T cell activation?
a. IL-2 receptor
b. Transcription factor NF-AT
c. CTLA-4
d. MHC class I
e. Serine protease
5. Which of the following amino acids is the most commonly used as a molecular activation switch
that is regulated by phosphorylation and dephosphorylation?
a. Tryptophan
b. Tyrosine
c. Alanine
d. Methionine
e. Lysine
1
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
6. During T cell activation, a cascade of signaling events results in PIP2 being cleaved into the active
intermediates diacylglycerol (DAG) and inositol-1,4,5 triphosphate (IP3) at the inner leaflet of the
membrane by phospholipase C (PLC). Where does IP3 then exert its primary effect to continue signal
transduction?
a. IP3 diffuses rapidly to the ER where it finds to an IP3 receptor and induces the
release of calcium
b. IP3 directly activates protein kinase C (PKC) which activates NFB
c. IP3 acts to dephosphoylate and activate NFAT
d. IP3 acts as a suppressor signal by blocking phosphorylation of p56lck to regulate
activation
e. IP3 diffuses rapidly to the nucleus and acts as a transcription factor to turn on immediate
genes
7. When T cells are activated and transition from naïve T cells to effector CTLs they begin to secrete
effector molecules when they encounter target cells. Which effector molecules are characteristic of a
CD8+ CTL cells response?
a. IL-2, IFN-gamma and TNF-beta
b. IL-17
c. Perforin, serine protease (also called granzyme B) and Fas ligand
d. IL-4, IL-5, IL-10
e. IFN-beta
8. Which of the following is an example of a molecule that can be described as a MAMP (microbial
associated molecular pattern)?
a. Hemagglutinin class 1 (H1)
b. Neuraminidase class 1 (N1)
c. Lipopolysaccharide (Endotoxin)
d. Microbial H-2 molecules
e. CD4
9. Positive and negative selection occurs in the thymus in order to remove dysfunctional cells. What
kinds of cells do these processes remove?
a. Cancer cells
b. Pre-T cells
c. CD4+ cells
d. CD8+ cells
e. autoreactive and anergic T cells
10. Which T cell product shares structural homology with some of the components of the
complement cascade?
a. Fas Receptor
b. IL-1 receptor
c. perforin
d. Interferon receptor
e. Serine protease
2
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
11. The major histocompatibility complex (MHC) is one of the most polymorphic clusters of genes
known. Predict an outcome in human populations that have reduced MHC polymorphism
a.
b.
c.
d.
They will be more resistant to new infections.
These populations will have a more pronounced chemotactic response.
Larger humoral responses will result in these populations
There will be potential “holes” in the immune response where specific antigens
are not presented.
e. There will be decreases in reproductive success.
12. Why are mice that are defective in the production of one cytokine often apparently normal in the
immune function?
a. Cytokines can have redundant functions, so another cytokine can sometimes be
substituted for the defective one.
b. Cytokines are antagonistic, so the absence of a cytokine ensures a better immune
response
c. Cytokines are synergistic, so the absence of a cytokine protects the mice from a
cytokine storm
d. The answers above (a-c) are all correct
e. Cytokines have suppressive effects on brain function, so the absence of a cytokine will
improve perception and avoidance of infectious pathogens
13. Peptide antigens generated in the cytosolic compartment (intracellular infection, e.g. virus) bind
to____ MHC molecules for presentation to____ T cells.
f. Class I; CD4+
g. Class II; CD4+
h. Class I; CD8+
i. Class II; CD8+
j. None of the above
14. Which of the following are essential molecules on the plasma membrane that are required for
efficient antibody-dependent cell-mediated cytotoxicity (ADCC)?
a. Complement proteins
b. MHC I or MHC II recognition receptors
c. CD28
d. Fc receptors
e. Toll like receptors (TLRs)
15. During negative selection in the thymus, what cellular function is activated to eliminate the 9598% of the cells that fail?
a. These cells acidify their environment
3
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
b. These cells accumulate in the lymph nodes
c. These cells apoptose
d. These cells aggregate around the high endothelial veinules (HEV)
e. These cells abrogate TcR/MHC interactions
16. How might you verify that an individual had been successfully vaccinated with the flu vaccine?
a. Use RT-PCR to measure antibody concentrations
b. Test for the total number of T cells in circulation
c. Measure the ability of T cells from the vaccinated patient to kill influenza-infected
target cells from a pig
d. Measure the presence of cells expressing an influenza-specific TcR using MHC
class I multimers complexed with an influenza peptide
e. All of the above would work
17. A mouse is infected with Listeria monocytogenes (L.m.). L.m. is an intracellular bacterium that
has the ability polymerize host cell actin as a “rocket tail” that the bacterium can use to propel itself
into the adjacent cell. The presentation of L. monocytogenes bacterial peptides to immune cells
during the process of developing adaptive immunity mainly involves:
a. MHC class II proteins
b. MHC class I proteins
c. CD4
d. CLIP
e. Both b and c
18. Some infections down-regulate the expression of MHC on the surfaces of cells. These cells with
reduced levels of MHC are detected and killed by:
a. Th2 T cells expressing cytokines that support humoral immunity
b. Th17 cells that secrete IL17
c. Natural Killer (NK) cells
d. CD8 cytotoxic T cells
e. Macrophages stimulated by Th1 helper cells
19. There are two main ways in which the complement cascade can be activated. The two main
components of complement activation are:
a. Antibody bound to antigen, and endotoxin from gram negative bacteria
b. The chemokines, and the cytokines
c. IgG, and IgD.
d. Calcium release, and lipid hydrolysis
e. Perforin, and serine esterases.
20.T cells in the thymus that bind too tightly to self peptide:
a. Undergo apoptosis because they have failed negative selection
4
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
b. Undergo apoptosis because they have failed positive selection
c. Leave the thymus so they can be killed by professional phagocytic cells
d. All of the above
e. Both B and C are true
21 . The dual recognition phenomenon that was originally described by Zinkernagel and Doherty
requires
a.
b.
c.
d.
e.
Simultaneous recognition of peptide and MHC by the TcR
Sequential recognition of the peptide by two helper T cells
Recognition of foreign peptide and co-stimulatory molecule
All of the above
None of the above
22. An enzyme which puts a phosphate group on a protein molecule is called a
a. Co-receptor
b. ITAM
c. Kinase
d. Phosphatase.
e. Receptor
23. The class I MHC processing pathway primarily
a. Processes antigens that are present in the cytosol.
b. Processes antigen from the extracellular environment
c. Generates peptides, complexes them with class I MHC molecules for presentation to
helper T cells
d. Generates peptides, complexes them with class I MHC molecules for presentation to
NK cells
e. Is involved in the process of the antibody response
24. Th1 and Th2 cells can be distinguished from each other by
a. The expression of specific differentiation antigens on their plasma membranes.
b. The speed with which they proliferate in response to antigen stimulation.
c. The specific set of cytokines made by each cell type.
d. The fact that the Th1 cells stimulate endocrine function while the Th2 cells stimulate
paracrine function.
e. The Th1 cells are immortal while the Th2 cells have limited lifespan.
25. The endocytic pathway for processing exogenous antigen relies on the ______________ to prevent
endogenous antigens from binding to class II antigen binding cleft
a. The invariant CLIP protein
b. 2M protein
c. MHC class I alpha chain
d. TAP
5
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
e. Calmodulin
26. The major histocompatibility complex (MHC) is one of the most polymorphic clusters of genes
known. Potential reasons for these polymorphisms include the possibility that
a. The more heterogenous the population, the more likely some individuals in the
population will be able to present antigen from a new infectious organism.
b. Polymorphisms protect individuals from the damaging effects of an allograft.
c. Multiple antibody sequences are encoded by these polymorphisms
d. There are many kinases that are encoded by the MHC, and many signal transduction
cascades that are thus regulated.
e. The polymorphisms arise from inbreeding depression.
27. Which of these proteins are NOT members of the immunoglobulin supergene family?
a. CD3
b. IgM
c. CD4
d.  (zeta), and  (eta) polypeptides of the TcR
e. CD8
28. Why is a live virus thought to elicit both cell mediated immunity and humoral immunity while
killed virus only provokes a humoral response?
a. Viral antigens stimulate all immune cells
b. Proliferating viruses do not kill macrophages
c. Only proliferating virus can activate the cytotoxic T cells to kill the infected target
while live and inactive viral particles released from host cells can each activate
antibody production
d. Live virus is never an effective immunogen
e. Humoral responses do not recognize live viruses
29. What is an ITAM?
a. This is a molecular motif important in complement activation
b. This is a genetic sequence that regulates Immunoglobulin rearrangement
c. This is a specific kind of CD4 molecule
d. This is an olfactory chemosignal encoded within the MHC
e. This is a motif recognized by cytosolic proteins in the process of cellular activation
30. What kinds of cells are responsible for delayed type hypersensitivity
a. Macrophages and T cells
b. Dendritic cells and B cells
c. Neutrophils and macrophages
d. Eosinophils and basophils
e. Epithelial cells and monocytes
6
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
Answer the next questions with a short sentence.
31. What are the three fundamental assumptions that were made about a TcR in the experiments
that isolated probes capable of identifying the genes that encoded the TcR alpha and beta
polypeptides?
a. The TcR is membrane bound
b. The TcR is not expressed in B cells
c. T cell clones will independently and uniquely rearrange.
32. Why is “herd immunity” important as a way to protect those individuals who cannot be
successfully immunized?
By preventing the spread of infection through a population so that
immunocompromised/un-immunized individuals are not exposed.
33. What is an important reason why injection of a cytokine such as IL-2 may be a dangerous
approach to therapeutic manipulation of the immune response?
Unregulated cytokine may provoke a dangerous cytokine storm leading to
multiple organ dysfunction syndrome and death.
34. Why is the process of apoptosis important in limiting the possibility of autoimmune disease?
Apoptosis retains in blebs the intracellular constituents that might provoke and
perpetuate autoimmune diseases (e.g. chromatin + DNA).
(Partial credit given to answers regarding negative selection)
7
MCB 4211, Fall 2015
Last, First name_____________________Student ID # ____________________
READ ALL THE CHOICES AND SELECT THE BEST
45. What cellular characteristics do forward scatter (FSC) and side scatter (SSC) indicate when used
in a flow cytometry analysis?
FSC= cellular size
SSC= internal cell complexity
8