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Biol 430
Question Bank
Innate Immunity
1. Inflammation would be best described as:
A. the combined response of the innate and acquired immune responses.
B. the effector response of B- and T-cells.
C. a set of innate responses to infection or wounding.
D. the swelling of skin at the site of infection.
2. At an inflammation site, what physiological processes cause:
A. tissue swelling: ______________________________
B. redness: ______________________________
3. “Pathogen-associated molecular patterns” are:
A. pathogen-specific antigens recognized by the acquired immune system.
B. molecules of generic structure widely found among pathogens.
C. the arrangement of pathogens within an infected tissue.
D. toxic molecules released by pathogens.
4. List 5 examples of pathogen associated “danger signals”
1.
4.
2.
5.
3.
5. An example of external effector response of myeloid cells is:
A. enhanced phagocytosis
B. hydrolytic enzymes of granules
C. ClO- found in lysosomes of macrophages
D. the respiratory burst
6. For macrophages, identify…
Two oxygen-dependent killing mechanisms
Two oxygen-independent killing mechanisms
7. The “acute phase response” includes all of the following, EXCEPT:
A. C-reactive protein
B. fibrinogen
C. complement proteins
D. antibodies
Biol 430
Question Bank
Innate
Page 1
8. Explain why each of these statements about the ‘membrane attack complex’ (MAC) is
incorrect.
A. The structure of the MAC differs for the classical and alternative pathways.
B. C9 is activated through proteolytic cleavage by C8.
C. Activation of C1 leads eventually to the formation of a single MAC.
D. The presence of MAC on a cell acts as an opsonin.
9. This diagram shows the process of _____________________
Identify the components labeled as:
A. ___________
C. ___________
B. ___________
D. ___________
Two tissues in which clearing of immune complexes
will occur are _______________ and ____________.
10. Using the following diagram:
A. Add to the diagram the names of complement peptides in the order of their
activation in the classical complement cascade, and show the small peptides
being released (as illustrated for C3a).
B. Identify and draw lines that separate the initiation, enzymatic, and membrane
attack stages.
C. Describe how activation of the “alternative pathway” differs from that of the
classical pathway?
D. Which step in this diagram does not occur in the lectin pathway?
Biol 430
Question Bank
Innate
Page 2
11. One of the most powerful techniques for revealing the function(s) of a protein is
preparation of a ‘knockout mouse’, in which the gene for a particular protein has been
made nonfunctional. Suppose you prepared strains of mice, each with the gene for a
particular component of the complement system knocked out. Predict the effect on
complement related functions for each mouse strain as “NE” = no effect, “D” = process or
function decreased, “A” = process or function abolished.
Component knocked out
C1 C4 C3 C6 Factor B
Predicted affect on complement activation
Formation of
classical
C3 convertase
Formation of
alternative
C3 convertase
Formation of
classical
C5 convertase
Formation of
alternative
C5 convertase
Predicted affect on effector functions
Complement
Mediated
opsonization
Leukocyte
chemotaxis
Bacterial cell
lysis
12. Match each of the following complement components or processes with the most
appropriate descriptions.
Component or process
Description
a. ___ C4, C2 and C3
1. classical C5 convertase
b. ___ C9
2. opsonin of immune complexes
c. ___ Factor B and Factor D
3. a complement regulatory protein
d. ___ C3  C3a + C3b
4. proteins of the alternative pathway
e. ___ C4b2a3b
5. polymerizes to form membrane pore
f. ___ C3b
6. receptor for C3b
g. ___ CR1
7. are all anaphylatoxins
h. ___ C6, C7, C8 and C9
8. components of enzymatic stage
i. ___ C4a, C3a, C5a
9. initiates lectin pathway
j. ___ MBL
10. this reaction will occur spontaneously
k. ___ C1-Inhibitor
11. comprise membrane attack stage
Biol 430
Question Bank
Innate
Page 3
13. For each of the following pairs of complement peptides, circle the name of the small
soluble fragment
C2a or C2b
C3a or C3b
C4a or C4b
C5a or C5b
A. Which of the above fragments is/are important opsonins?
B. Which are important in chemotaxis?
14. Complement activation plays a role in the tissue damage resulting from a myocardial
infarction (heart attack) and stroke, hyperacute graft rejection, and certain types of
autoimmune diseases. A study by Nauta et al (2002) the mechanism by which complement
can activate apoptosis and cause tissue damage was investigated. Apoptosis, or
programmed cell death, leads to the orderly destruction of a cell without necrosis and
release of cytoplasmic content, and involves the activation of caspase proteases.
The experiments were performed using cultured rat mesangial cells (RMC). To
trigger complement attack, the cells were opsonized by exposing to a complementactivating antibody (ER4G) which was followed by a short exposure of the cells to rat
serum. Apoptotic cells were quantified using FACS after treating the cells with annexin V
and propidium iodide (PI). In apoptotic cells and necrotic cells, phosphatidylserine is
exposed from the cell membrane and can be bound by annexin V. Membrane rupturing in
necrotic cells allows uptake of propidium iodide (PI); thus, apoptotic cell can be
fluorescently labeled as annexin V+/PI−, whereas necrotic cells will be annexin V+/PI+.
In one set of experiments, the
cells were exposed to either normal rat
serum or (NRS) or C6-deficient rat
serum (C6d), and the results are shown
in this figure.
A. In the Figures, label the cell
clusters that are annexin
V−/PI−, annexin V+/PI−, and
annexin V+/PI+. Which
types of cells are normal,
apoptotic and necrotic?
B. Which serum caused the
greatest increase in
apoptotic cells? Explain why did the other serum fail to do so.
C. What do these results say about which stage of the complement pathway is
needed to trigger apoptosis? Explain.
(continued on next page)
Biol 430
Question Bank
Innate
Page 4
In a different experiment, cells were stained
with a fluorescent antibody the reacts only
with the active form of caspase-3, part of the
apoptosis activation cascade. Cells were
otherwise treated as described above. The
results are shown in this figure.
D. Why were some cells treated with
culture medium instead of serum?
E. Do the results for NRS and C6d agree with your expectations and the results of
the first experiment? Explain.
F. What is the effect of including the compound z-vad? Why might this be
included in one of the experiments?
Biol 430
Question Bank
Innate
Page 5