8. Yersinia pes s, the causa ve agent of the bubonic plague, has mul ple mechanisms of
immune evasion. This Gram-nega ve bacterium is transmi ed from fleas (body temperature 26
deg C) to humans (body temperature 37 deg C) by flea bites. Studies have shown that the
lipopolysaccharide (LPS) produced by Y. pes s grown at 37 deg C is about 10-fold less potent at
s mula ng TLR4 signaling than is the Y. pes s LPS from bacteria grown at 26 deg C. When these
two forms of Y. pes s LPS are compared for their abili es to induce responses from human
macrophages, one would expect that the 26 deg C Y. pes s LPS would result in:
A. Increased produc on of an microbial pep des
B. Increased produc on of TNF-a and IL-6
C. Reduced produc on of IL-10
D. Increased ac va on of the inflammasome
E.Reduced produc on of Type 1 interferons -correct answersB. Increased produc on of TNF-a
and IL-6
1. An infant with recurrent bacterial and fungal infec ons is suspected to have an
immunodeficiency disease. Within two days a er exposure to a pathogen, the organisms have
proliferated to dangerous levels requiring immediate systemic an bio c treatment. It is
unlikely that this infant has a defect in B or T lymphocyte responses to the infec on because:
A. Systemic infec ons of bacteria and fungi are usually cleared by the spleen.
B. Bacteria and fungi do not require B cell or T cell responses for their clearance.
C. Bacteria and fungi are not efficiently transported to draining lymph nodes to ini ate adap ve
immune responses.
,D. The defec ve immune response occurs too rapidly following infec on to be due to a defect
in B or T lymphocytes responses.
E. Adap ve immune responses require dendri c cells to take up and degrade pathogens. -
correct answersD. The defec ve immune response occurs too rapidly following infec on to be
due to a defect
in B or T lymphocytes responses.
2. In pa ents with lymphomas, the cancer cells invade the bone marrow and destroy the
environment required for normal hematopoiesis. This leads to bone marrow failure, which
disrupts the produc on of hematopoie c cell lineages. All of the following cell types would be
affected by this EXCEPT:
A. Red blood cells
B. Endothelial cells
C. Lymphocytes
D. Dendri c cells
E. Neutrophils -correct answersB. Endothelial cells
3. Epithelial surfaces provide the first line of defense against infec on by the use of several
types
of mechanisms. What is a chemical way to fend off pathogens?
A. Secre on of an microbial pep des by epithelial cells
B. Joining of epithelial cells by ght junc ons
C. Produc on of mucus, tears, or saliva in the nose, eyes, and oral cavity
D. Movement of mucus by cilia
E. Peristalsis in the gastrointes nal tract -correct answersA. Secre on of an microbial pep des
by epithelial cells
,4. Neutrophil secret defensins, which are:
A. Enzymes
B. Glycolipids
C. Short amphipathic pep des
D. Carbohydrates
E. Reac ve oxygen species (ROS) -correct answersC. Short amphipathic pep des
5. Which of the following statements is TRUE of lysozyme?
A. Lysozyme is a cytoplasmic organelle
B. Lysozyme ac vates complement
C. Lysozyme is a protease
D. Lysozyme splits pep doglycan
E. Lysozyme is released by mast cells -correct answersD. Lysozyme splits pep doglycan
6. True or False: The classical and lec n pathways of complement ac va on converge at the
step
of C3 ac va on. Moreover, the ini a ng steps of each pathway use protein components and
enzyma c mechanisms that share high similarity with each other. -correct answersTRUE
7. Which one of the following is NEITHER a C3 convertase NOR a C5 convertase?
A. C4b2a3b
B. C3bBb
C. C4b2a
D. C3(H2O)Bb
E. C1q, C1r and C1s -correct answersE. C1q, C1r and C1s
, 8. The membrane a ack complex consists of
A. C4b2a
B. (C3b)2Bb
C. C5b, 6, 7, 8, 9
D. C3a or C5a
E. MASP-1, -2, and -3 -correct answersC. C5b, 6, 7, 8, 9
9. True or False: The C3 convertase of the alterna ve complement pathway amplifies the overall
magnitude of complement ac va on regardless of which of the three pathways ini ated the
complement ac va on ini ally.
A. This statement is true.
B. This statement is false. -correct answersTRUE
10. The Toll-like receptor 3 (TLR3) pa ern recogni on receptor recognizes:
A. Bacterial lipopep des
B. Flagellin
C. Lipopolysaccharide (LPS) from Gram nega ve bacteria
D. Double-stranded RNA (dsRNA)
E. Double-stranded DNA (dsDNA) -correct answersD. Double-stranded RNA (dsRNA)
11. The forma on of the C3 convertase is a key step in complement ac va on that occurs in all
three complement pathways. This enzyme cleaves C3 in blood plasma, leading to a
conforma onal change in the C3b fragment that exposes its reac ve thioester group. The
ac vated C3b is poten ally harmful to the host, if it becomes covalently a ached to a host cell,
rather than to the surface of a pathogen. This deleterious outcome is largely avoided by:
A. The inability of ac ve C3b to diffuse away in the blood plasma.
immune evasion. This Gram-nega ve bacterium is transmi ed from fleas (body temperature 26
deg C) to humans (body temperature 37 deg C) by flea bites. Studies have shown that the
lipopolysaccharide (LPS) produced by Y. pes s grown at 37 deg C is about 10-fold less potent at
s mula ng TLR4 signaling than is the Y. pes s LPS from bacteria grown at 26 deg C. When these
two forms of Y. pes s LPS are compared for their abili es to induce responses from human
macrophages, one would expect that the 26 deg C Y. pes s LPS would result in:
A. Increased produc on of an microbial pep des
B. Increased produc on of TNF-a and IL-6
C. Reduced produc on of IL-10
D. Increased ac va on of the inflammasome
E.Reduced produc on of Type 1 interferons -correct answersB. Increased produc on of TNF-a
and IL-6
1. An infant with recurrent bacterial and fungal infec ons is suspected to have an
immunodeficiency disease. Within two days a er exposure to a pathogen, the organisms have
proliferated to dangerous levels requiring immediate systemic an bio c treatment. It is
unlikely that this infant has a defect in B or T lymphocyte responses to the infec on because:
A. Systemic infec ons of bacteria and fungi are usually cleared by the spleen.
B. Bacteria and fungi do not require B cell or T cell responses for their clearance.
C. Bacteria and fungi are not efficiently transported to draining lymph nodes to ini ate adap ve
immune responses.
,D. The defec ve immune response occurs too rapidly following infec on to be due to a defect
in B or T lymphocytes responses.
E. Adap ve immune responses require dendri c cells to take up and degrade pathogens. -
correct answersD. The defec ve immune response occurs too rapidly following infec on to be
due to a defect
in B or T lymphocytes responses.
2. In pa ents with lymphomas, the cancer cells invade the bone marrow and destroy the
environment required for normal hematopoiesis. This leads to bone marrow failure, which
disrupts the produc on of hematopoie c cell lineages. All of the following cell types would be
affected by this EXCEPT:
A. Red blood cells
B. Endothelial cells
C. Lymphocytes
D. Dendri c cells
E. Neutrophils -correct answersB. Endothelial cells
3. Epithelial surfaces provide the first line of defense against infec on by the use of several
types
of mechanisms. What is a chemical way to fend off pathogens?
A. Secre on of an microbial pep des by epithelial cells
B. Joining of epithelial cells by ght junc ons
C. Produc on of mucus, tears, or saliva in the nose, eyes, and oral cavity
D. Movement of mucus by cilia
E. Peristalsis in the gastrointes nal tract -correct answersA. Secre on of an microbial pep des
by epithelial cells
,4. Neutrophil secret defensins, which are:
A. Enzymes
B. Glycolipids
C. Short amphipathic pep des
D. Carbohydrates
E. Reac ve oxygen species (ROS) -correct answersC. Short amphipathic pep des
5. Which of the following statements is TRUE of lysozyme?
A. Lysozyme is a cytoplasmic organelle
B. Lysozyme ac vates complement
C. Lysozyme is a protease
D. Lysozyme splits pep doglycan
E. Lysozyme is released by mast cells -correct answersD. Lysozyme splits pep doglycan
6. True or False: The classical and lec n pathways of complement ac va on converge at the
step
of C3 ac va on. Moreover, the ini a ng steps of each pathway use protein components and
enzyma c mechanisms that share high similarity with each other. -correct answersTRUE
7. Which one of the following is NEITHER a C3 convertase NOR a C5 convertase?
A. C4b2a3b
B. C3bBb
C. C4b2a
D. C3(H2O)Bb
E. C1q, C1r and C1s -correct answersE. C1q, C1r and C1s
, 8. The membrane a ack complex consists of
A. C4b2a
B. (C3b)2Bb
C. C5b, 6, 7, 8, 9
D. C3a or C5a
E. MASP-1, -2, and -3 -correct answersC. C5b, 6, 7, 8, 9
9. True or False: The C3 convertase of the alterna ve complement pathway amplifies the overall
magnitude of complement ac va on regardless of which of the three pathways ini ated the
complement ac va on ini ally.
A. This statement is true.
B. This statement is false. -correct answersTRUE
10. The Toll-like receptor 3 (TLR3) pa ern recogni on receptor recognizes:
A. Bacterial lipopep des
B. Flagellin
C. Lipopolysaccharide (LPS) from Gram nega ve bacteria
D. Double-stranded RNA (dsRNA)
E. Double-stranded DNA (dsDNA) -correct answersD. Double-stranded RNA (dsRNA)
11. The forma on of the C3 convertase is a key step in complement ac va on that occurs in all
three complement pathways. This enzyme cleaves C3 in blood plasma, leading to a
conforma onal change in the C3b fragment that exposes its reac ve thioester group. The
ac vated C3b is poten ally harmful to the host, if it becomes covalently a ached to a host cell,
rather than to the surface of a pathogen. This deleterious outcome is largely avoided by:
A. The inability of ac ve C3b to diffuse away in the blood plasma.
