Exam 3 (Lect. 22-26)

Question 1

Which of the following is associated with antigen presentation by phagocytes, but not by epithelial
cells?
A. MHC1 picks up an external antigen circulating in the blood serum.
B. MHC2 picks up an antigen from the phagocyte’s cytoplasm.
C. MHC1 picks up an antigen from the phagolysosome.
D. MHC2 picks up an external antigen circulating in the blood serum.
E. MHC2 picks up an antigen from the phagolysosome.

Answer 1

MHC2 picks up an antigen from the phagolysosome.

Question 2

Which of the following is NOT common to all three complement activation pathways?
A. The inflammatory response is triggered by C3a and C5a.
B. The adaptive immune response is needed for activation of the pathway.
C. Complement protein C3b is needed as part of the C5 convertase.
D. A molecule from your blood serum must bind the surface of a pathogen.
E. The MAC is formed from C5b and C6 - C9.

Answer 2

The adaptive immune response is needed for activation of the pathway.

Question 3

Bacteria respond to phagocytosis by . . .
A. forming granulomas
B. releasing their capsule antigens
C. producing leukocidins
D. enhancing motility to swim out of the phagocyte
E. producing an oxidative burst to kill the phagocyte

Answer 3

producing leukocidins

Question 4

MHC Class II receptors . . .
A. Are found only on phagocytes and B-cells
B. Pick up antigen from the infected cell’s cytoplasm
C. Serve as binding receptors for TC cells
D. bind to the CD8 receptor on T cells
E. are found on T cells and used as transporters for cytokine secretion

Answer 4

Are found only on phagocytes and B-cells

Question 5

How does interferon fight a viral infection in an infected host?
A. It is a viricidal protein.
B. It induces antiviral proteins (AVP) in virus-infected cells.
C. It boosts the production of B cells in a virus-infected host.
D. It activates inactive AVPs in virus-infected cells.
E. It is produced in virus-infected cells and induces AVP in neighboring cells.

Answer 5

It is produced in virus-infected cells and induces AVP in neighboring cells.

Question 6

Which of the following is required for granuloma formation?
A. B cells must continually secrete antibodies
B. TC cells must continually secrete cytotoxins
C. NK cells must continually secrete perforins
D. Macrophages must continually secrete chemokines
E. APC cells must continually secrete antigens

Answer 6

Macrophages must continually secrete chemokines

Question 7

Which of the following is correct regarding the body’s interferon defense system?
A. It can be activated when antibodies bind to an organism.
B. Cells that produce interferon apoptose when infected by a virus.
C. Interferon induces the production of antiviral proteins in adjacent cells.
D. Interferon is only produced by antigen presenting cells (APCs).
E. Interferon is produced in the phagolysosome of macrophages with activated TLRs.

Answer 7

Interferon induces the production of antiviral proteins in adjacent cells.

Question 8

The three complement activation systems share many common features, but there are also
differences. Which of the following is NOT common to all three complement pathways?
A. Diapedesis is induced by peptide C3a
B. Properdin is required to stabilize the C5 convertase
C. C3b opsonizes foreign cells for phagocytosis
D. A pore complex is assembled and inserted into a foreign cell to lyse it
E. PMNs are recruited to the site of complement activation by peptide C5a

Answer 8

Properdin is required to stabilize the C5 convertase

Question 9

Why does a bacterium produce antioxidants?
A. To help your body fight off infections from other bacteria.
B. To signal phagocytes to engulf it.
C. To survive the harsh environment inside the phagolysosome.
D. The bacterium is producing its own chemoattractants.
E. To kill the phagocyte that is trying to engulf it.

Answer 9

To survive the harsh environment inside the phagolysosome.

Question 10

Some bacteria live and divide inside the phagolysosome. What will be a symptom associated with
a chronic infection of a patient with such a bacterium?
A. Clumps of infected macrophages and TH cells will be seen in the patient’s tissues.
B. There will be a lower-than-normal number of phagocytes in the patient’s body.
C. The patient will suffer from constant high fever.
D. The patient will not produce antibodies against the bacterium.
E. The patient will suffer hypovolemia and DIC.

Answer 10

Clumps of infected macrophages and TH cells will be seen in the patient’s tissues.

Question 11

Which of the following is associated with antigen presentation by dendritic cells, but not by
epithelial cells?
A. MHC1 picks up an external antigen circulating in the blood serum.
B. MHC2 picks up an antigen from the phagocyte’s cytoplasm.
C. MHC1 picks up an antigen from the phagolysosome.
D. MHC2 picks up an external antigen circulating in the blood serum.
E. MHC2 picks up an antigen from the phagolysosome.

Answer 11

MHC2 picks up an antigen from the phagolysosome.

Question 12

Which of the following is NOT a consequence of activating the complement cascade on the surface
of a bacterium?
A. Peptide C3b attaches to the bacterium, making it easier to phagocytize.
B. Peptide C5b recruits a pore complex to kill the bacterium.
C. Convertases are assembled that proteolyze other complement proteins.
D. Peptide C3a induces B cells to produce antibodies that attach to the bacterium.
E. Peptide C5a recruits PMNs to the site of the infection, where they engulf bacteria.

Answer 12

Peptide C3a induces B cells to produce antibodies that attach to the bacterium.

Question 13

One of the complement activation pathways is called the “alternate” pathway. What is different
between this pathway and the “classical” pathway?
A. It kills bacteria in a different manner than the classical pathway.
B. It requires a bacterial surface to be coated with lectins.
C. It only kills infected “self” cells, rather than pathogenic bacteria.
D. It can be activated even before the humoral immune response is active.
E. It alternates between inducing inflammation and keeping fever from getting too high.

Answer 13

It can be activated even before the humoral immune response is active.

Question 14

Which of the following is required for granuloma formation?
A. production of antibodies against a bacterium
B. epithelial cell damage
C. persistent antigen presence inside macrophages
D. binding of the B7 on APCs to CD28 on TC cells
E. high titer of a pathogen circulating in the blood

Answer 14

persistent antigen presence inside macrophages

Question 15

Which of the following could be considered to be a phagocyte?
A. TC cell
B. TH cell
C. lymphocyte
D. antigen presenting cell
E. mast cell

Answer 15

antigen presenting cell

Question 16

We said that MHC2 is mainly for presentation of exogenous antigens, whereas MHC1 is mainly
for presentation of endogenous antigens. Why is this so?
A. MHC2 is on the outside of cells, MHC1 is on the inside.
B. MHC2 binds to bacteria to allow macrophages to engulf the bacteria.
C. MHC1 is found in the nucleus of infected cells, MHC2 in the cell membrane.
D. MHC1 is involved in elimination of antibodies that recognize self antigens.
E. MHC2 passes through the endocytic vesicle on its way to the cell surface.

Answer 16

MHC2 passes through the endocytic vesicle on its way to the cell surface.

Question 17

What is the purpose for our immune system to opsonize bacterial cells?
A. It makes the bacteria easier for the oxidative burst and hydrolases to digest.
B. It causes phagocytes to produce more lysosomes.
C. It makes the surface of the bacteria more slippery so that we can excrete them better.
D. It adds surface features to the bacterium that makes it easier for our cells to recognize.
E. It is a way to neutralize bacteria so that they do not attach to our cells and infect us.

Answer 17

It adds surface features to the bacterium that makes it easier for our cells to recognize.

Question 18

Granuloma formation involves all of the following EXCEPT . . .
A. antibodies
B. cytokines
C. macrophages
D. bacteria
E. T cells

Answer 18

antibodies

Question 19

Which of the following statements is true of MHC-II, but not of MHC-I?
A. It must be matched in transplanted tissues or the transplant will be rejected.
B. It mainly displays antigens from the phagolysosome.
C. It typically displays self antigens as well as foreign antigens.
D. It is more important for fighting viral infections than bacterial infections.
E. It recruits TC cells and attaches specifically to them so the infected APC will be killed.

Answer 19

It mainly displays antigens from the phagolysosome.

Question 20

How is interferon produced during an infection?
A. It is produced by induction of viral genes in the phagolysosome.
B. Bacteria produce it in response to the phagocyte oxidative burst.
C. A second-messenger pathway induces it when viral RNA binds to an RLR receptor.
D. It is produced when MHC-I phosphorylates a response regulator in infected cells.
E. TH cells produce it when they bind to MHC-II that is displaying viral antigens.

Answer 20

A second-messenger pathway induces it when viral RNA binds to an RLR receptor.

Question 21

Which of the following is true of infections that are characterized by granuloma formation?
A. Bacteria that cause these infections lack PAMPs on their surface.
B. APCs associated with these infections fail to engulf bacterial pathogens.
C. Bacteria that cause these infections produce many leukocidins and oxidants.
D. Bacteria prevent lysosomes in infected macrophages from fusing with phagosomes.
E. Infected macrophages fail to produce MHC-II, and so are not recognized by IgG.

Answer 21

Bacteria prevent lysosomes in infected macrophages from fusing with phagosomes.

Question 22

What is the function of a Toll-like receptor?
A. It allows macrophages and dendritic cells to bind specifically to pathogens.
B. It allows TH cells to bind specifically to B cells.
C. It allows pathogens to bind specifically to epithelial cells.
D. It allows bacteria to bind the FC part of antibodies.
E. It allows the immune system to recognize when a viral infection has occurred.

Answer 22

It allows macrophages and dendritic cells to bind specifically to pathogens.

Question 23

What molecule is typically recognized by the immune system to signal that a cell has been infected
by a virus?
A. Complement protein C3b
B. Viral capsomeres
C. Viral envelope lipids
D. Viral spike proteins
E. Double stranded RNA

Answer 23

Double stranded RNA

Question 24

How does interferon (IFN) function during a viral infection?
A. Cells that produce IFN apoptose when infected by a virus.
B. IFN is an oxidant that kills the virus by oxidizing viral capsid proteins.
C. IFN is an inducer that turns on genes for antiviral proteins in neighboring cells.
D. IFN is a cytotoxin that kills neighboring cells to prevent them from getting infected.
E. IFN is a chemokine signal that induces antibody production by TC cells.

Answer 24

IFN is an inducer that turns on genes for antiviral proteins in neighboring cells.

Question 25

Some bacteria have evolved the ability to prevent lysosome fusion to a phagosome. These bacteria
can therefore avoid . . .
A. phagocytosis
B. granuloma encasement
C. neutrophil attacks
D. opsonization
E. the oxidative burst

Answer 25

the oxidative burst

Question 26

What is a leukocidin?
A. a type of leukocyte
B. a type of stem cell found in the blood
C. a toxin produced by bacteria to kill macrophages
D. a toxin produced by macrophages to kill bacteria
E. a cytokine that induces apoptosis in infected cells

Answer 26

a toxin produced by bacteria to kill macrophages

Question 27

Which of the following is true about antigen presentation on MHC class I?
A. It requires protein digestion by the proteasome.
B. It only occurs in professional APCs.
C. It requires altering the route of membrane vesicles through the endomembrane system.
D. Only foreign antigens are presented on MHC class I.
E. TH cells are stimulated by binding to antigens presented on MHC-I

Answer 27

t requires protein digestion by the proteasome.

Question 28

Antigens displayed on MHC class II come from . . .
A. the cytoplasm of the cell that displays them
B. the endoplasmic reticulum of the cell that displays them
C. the surface of T-lymphocytes that have engulfed bacteria
D. the phagolysosome of the cell that displays them
E. the endoplasmic reticulum of APCs, but the cytoplasm of other cells

Answer 28

the phagolysosome of the cell that displays them

Question 29

What is the role of antibodies in the innate immune response?
A. They can activate the B-cell response.
B. They can activate the synthesis of antimicrobial peptides.
C. They can detect damage to the skin.
D. They can induce the proliferation of myeloid cells.
E. Antibodies are adaptive, and have no role in innate immunity.

Answer 29

They can activate the synthesis of antimicrobial peptides.

Question 30

Which complement-associated term is NOT correctly matched with its function?
A. C3b – enhances phagocytosis
B. Lectin – digests the C5 protein
C. C3a – induces diapedesis
D. C5b – recruits a lytic pore complex
E. C3b – initiates one of the complement pathways

Answer 30

Lectin – digests the C5 protein

Question 31

Which of the following are produced inside a phagolysosome?
A. Hydrolases and Interleukins
B. Digestive enzymes and MHC-II
C. Peroxides and Antimicrobial complement peptides
D. Cytokines and Cytotoxins
E. Hydrolases and Peroxides

Answer 31

Hydrolases and Peroxides

Question 32

A patient comes to your clinic with the structures shown at right
on his vocal cords. You take a biopsy of the structure indicated by the
arrow. PCR primers are prepared comple-mentary to the 3’ ends of a
bacterial gene, and a reaction is performed on the biopsied tissue. The
results are shown after electrophoresis. What is the best interpretation
of this data?
A. The PCR has been done wrong. One primer should be complementary to the 3’ end and the
other should be complementary to the 5’ end of the gene.
B. The patient’s macrophages are in the process of digesting the bacteria and releasing
the DNA.
C. The patient has a granuloma, and may need long term antibiotics to treat it.
D. The patient has a tumor, which was caused by insertion of bacterial DNA.
E. The bacterium is actively replicating its DNA, which was detected by the PCR.

Answer 32

The patient has a granuloma, and may need long term antibiotics to treat it.

Question 33

Which of the following correctly distinguishes MHC-I from MHC-II?
A. MHC-I picks up an antigen as it passes through the phagloysosome.
B. MHC-II displays only endogenous antigens.
C. MHC-I can display self antigens on the surface of uninfected cells.
D. MHC-II binds to TC cells, which destroy an infected cell.
E. MHC-I is found only on professional phagocytes and B cells.

Answer 33

MHC-I can display self antigens on the surface of uninfected cells.

Question 34

Which of the following is true regarding interferon  and ?
A. They are released from a cell to bind to receptors on nearby cells.
B. Their production is induced by viral capsomeres.
C. They kill the cell that produces them.
D. They are produced in cells next to ones that have been infected by a virus.
E. They kill a virus by allosterically inhibiting viral replication enzymes.

Answer 34

They are released from a cell to bind to receptors on nearby cells.
B. Their production is induced by viral capsomeres.

Question 35

There are three complement activation pathways. How do these pathways differ?
A. The way the membrane attack complex is assembled
B. The way C3 and C5 proteins are hydrolyzed
C. The cytokines produced once the pathways have been activated
D. The cells that activate the pathway.
E. Some pathways, but not all, trigger an inflammatory response

Answer 35

The way C3 and C5 proteins are hydrolyzed

Question 36

Two things happen once a pathogen binds specifically to a dendritic cell (DC). They are . . .
A. The pathogen is engulfed, and the DC produces co-stimulatory molecules.
B. The DC stimulates the production of both antibodies and T cells.
C. The DC produces both B7 proteins and PRR proteins.
D. The pathogen is engulfed, and the DC begins to produce antibodies.
E. The DC begins to coat itself with MHC-I and with PRR proteins.

Answer 36

The pathogen is engulfed, and the DC produces co-stimulatory molecules.

Question 37

Bacteria that can survive inside the phagolysosome can do so because . . .
A. they fail to bind C3b to their surface
B. they produce leukocidins
C. their surface molecules are covered by a capsule
D. they produce antioxidants
E. they recruit neutrophils to neutralize the phagolysosome

Answer 37

they produce antioxidants

Question 38

Which of the following is a difference between endogenous and exogenous antigen presentation?
A. MHC-II presents only endogenous antigens.
B. Endogenous antigens bind to the TCR of a TH cell.
C. Endogenous antigens are always “self,” and exogenous are “foreign.”
D. Endogenous antigens are displayed only on professional APCs.
E. Endogenous antigens are processed by the proteasome, exogenous by the phagolysosome

Answer 38

Endogenous antigens are processed by the proteasome, exogenous by the phagolysosome

Question 39

How does interferon prevent viral replication?
A. By preventing the formation of dsRNA
B. By signaling cells to be ready to apoptose if a virus invades
C. By killing host cells after the virus has been assembled but before budding
D. By preventing the virus from binding to host cell receptors
E. By preventing the processing of viral polyproteins

Answer 39

By signaling cells to be ready to apoptose if a virus invades

Question 40

Which complement molecule is correctly matched with its function?
A. C5a – chemokine signaling molecule
B. C5b – part of a protease
C. properdin – stimulates the inflammatory response
D. C3b – lyses infected cells
E. C3a – an opsonin that binds to bacteria

Answer 40

C5a – chemokine signaling molecule

Question 41

In general, antibodies can defend against pathogens in any of six ways. However, IgM and IgA can
only use a few of these methods. Which of the following could be used by IgM or IgA to inactivate
pathogens?
A. Agglutination
B. Opsonization
C. Complement activation
D. NK cell activation
E. TH cell activation

Answer 41

Agglutination

Question 42

What parts of antibodies have great variability due to somatic recombination?
A. variable and constant regions
B. the Fc part only
C. alpha and beta chains
D. the heavy chain only
E. the Fab part only

Answer 42

the Fab part only

Question 43

The antibody type that is secreted by plasma cells one day after primary infection would most likely
be:
A. IgA
B. IgD
C. IgG
D. IgM
E. IgE

Answer 43

IgM

Question 44

Some antigens (T-independent) can activate B cells without the involvement of cellular immunity.
Which of the following would still occur in response to these antigens?
A. Memory B cells would be produced
B. B cell receptors would bind to the antigen
C. B cells would internalize the antigen
D. TH cells would bind to the B cells’ MHC2

Answer 44

B cell receptors would bind to the antigen

Question 45

A B cell recognizes an antigen, but there is no TH cell that also recognizes the antigen. What will
happen?
A. The B cell will become anergic.
B. The B cell will begin producing antibodies.
C. The TH cell will secrete cytokines to activate the B cell.
D. The B cell will not internalize the antigen.
E. The TH cell will kill the B cell

Answer 45

The B cell will become anergic.

Question 46

The process that ensures no circulating B cells recognize self antigens is called:
A. class switching
B. clonal selection
C. somatic recombination
D. clonal deletion
E. conjugation

Answer 46

clonal deletion

Question 47

How do antibodies actually kill foreign bacteria?
A. They bore a hole in the bacterial cell envelope, making the contents leak out.
B. They surround and engulf the bacterium.
C. They opsonize the bacterium, making it easier to phagocytize.
D. The Fab part directs a protease to the bacterium, which is then digested.
E. They anergize the bacterium, causing it to use so much energy that it dies

Answer 47

They opsonize the bacterium, making it easier to phagocytize.

Question 48

What is the major difference between IgG and IgA?
A. They have different variable regions.
B. IgA is produced by class switching, IgG by somatic recombination.
C. IgG is the first antibody to be produced, IgA is the second.
D. IgG is the major secreted antibody; IgA is found mainly in the blood.
E. The Fc region of the IgA heavy chain allows dimerization.

Answer 48

The Fc region of the IgA heavy chain allows dimerization.

Question 49

A patient is infected with Pasteurella multocida from a dog bite.
Two weeks later, the same patient is bitten and infected with P.
multocida again. The antibody titers were determined after the two
bites, and found to be as shown. What best explains this result?
A. This patient cannot develop memory B cells.
B. This patient has no TH cells.
C. The bacteria have not been engulfed by phagocytes.
D. TC cells have failed to completely clear the first infection.
E. This is the typical result. No special explanation is needed.

Answer 49

This patient cannot develop memory B cells.

Question 50

Which antibody class can cross the placenta to protect the fetus?
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM

Answer 50

IgG

Question 51

What parts of antibodies have great variability due to somatic recombination?
A. variable and constant regions
B. the Fc part only
C. alpha and beta chains
D. the heavy chain only
E. the Fab part only

Answer 51

the Fab part only

Question 52

What causes a B cell to become anergic?
A. It produces extra ATP by oxidative phosphorylation.
B. A TC cell binds to its MHC2 receptors rather than a TH cell.
C. Its MHC2 receptors present an antigen that is not recognized by a TH cell.
D. Its MHC1 receptors bearing foreign antigens are recognized by antibodies.
E. A TH cell binds to it and secretes stimulatory cytokines.

Answer 52

Its MHC2 receptors present an antigen that is not recognized by a TH cell.

Question 53

Immunoglobulin M (IgM) . . .
A. looks like this:
B. is the main serum antibody
C. is mostly secreted into the tissues and mucus membranes
D. is the first antibody produced in response to an infection
E. has a longer half-life than any of the other antibodies

Answer 53

is the first antibody produced in response to an infection

Question 54

The process responsible for antibody diversity . . .
A. puts the Fab and Fc regions together
B. joins heavy chains to light chains
C. begins as soon as a B cell comes into contact with an antigen
D. is initiated by cytokine signals from macrophages
E. is a genetic recombination that can only happen once in each B cell

Answer 54

is a genetic recombination that can only happen once in each B cell

Question 55

How are TH cells involved in the humoral immune response?
A. TH cells produce antibodies
B. Macrophages produce antibodies in response to TH cells
C. Antibodies are modified by TH cells so that they are active
D. TH cells kill infected cells by releasing perforin and inducing apoptosis
E. Cytokines from TH cells cause B cells to turn into antibody-producing plasma cells

Answer 55

Cytokines from TH cells cause B cells to turn into antibody-producing plasma cells

Question 56

Why are only a very small number of B cells activated in response to an infection?
A. Only a few B cells produce the B7 protein.
B. Only a few B cells have PMPs that recognize a pathogen.
C. Only a few B cells bind to both the specific antigen and a TH cell.
D. The cytokines the body produces bind specifically only to one type of B cell.
E. Most B cells are activated initially, but the ones that don’t respond to the infection are
later inactivated again.

Answer 56

Only a few B cells bind to both the specific antigen and a TH cell.

Question 57

What is the most correct statement about the selection process B cells must undergo before they
are released to the blood?
A. Recognizing any antigens in bone marrow causes B cells to apoptose.
B. B cell receptors must recognize self MHCs, but must not recognize antigens on the MHCs.
C. Failure to recognize a circulating antigen causes B cells to become anergic.
D. V-D-J combinations do not occur if they would produce antibodies against self antigens.
E. B cells fail to multiply unless they recognize a self antigen on an MHC2.

Answer 57

Recognizing any antigens in bone marrow causes to apoptose

Question 58

Which of the following can antibodies do to “fight” against both bacteria and viruses?
A. neutralize receptor binding proteins
B. lyse the virus or bacterium
C. initiate the formation of the membrane attack complex
D. bind to and inactivate toxins
E. initiate antibody-dependent cellular cytoxicity (ADCC)

Answer 58

neutralize receptor binding proteins

Question 59

The antibody type shown at right has what special feature?
A. It can cross the placenta to protect the fetus.
B. It can activate ADCC better than other antibody types.
C. It is involved in the Type I hypersensitivity response.
D. It is the major antibody found in mucus membranes.
E. It is the first antibody produced in response to an infection.

Answer 59

It is the major antibody found in mucus membranes.

Question 60

What cellular process allows billions of different antibody Fab fragments to be produced from only
a few hundred genes?
A. Somatic Recombination
B. Clonal Selection
C. Clonal Expansion
D. Class Switching
E. Promoter Multiplicity

Answer 60

Somatic Recombination

Question 61

Antibodies can “fight” bacterial infections in all of the following ways EXCEPT . . .
A. stop bacterial motility
B. attract NK cells
C. direct a pore complex to form in the bacterial membrane
D. activate TH cells to secrete cytokines
E. make bacteria easier for phagocytes to recognize

Answer 61

activate TH cells to secrete cytokines

Question 62

What can you conclude if you find the structure at right in a patient?
A. The patient has been recently infected.
B. The patient is a fetus.
C. The patient is suffering from allergies.
D. This is at least the second time the patient has had the same disease.
E. The patient is suffering an autoimmune disease.

Answer 62

The patient has been recently infected.

Question 63

What is the role of T cells in the antibody response?
A. TH cells initiate the V-D-J joining process.
B. TH cells engulf antigens for presentation to B cells.
C. TH cells stimulate B cell division and differentiation.
D. TC cells secrete one of the types of antibodies.
E. T cells play no role in the antibody response.

Answer 63

TH cells stimulate B cell division and differentiation.

Question 64

Which parts of the antibody shown at the right undergo somatic recombination?
A. all 4 parts labeled ‘A’
B. both parts labeled ‘B’
C. all 4 parts labeled ‘C’
D. all 4 parts labeled ‘D’
E. The whole antibody undergoes somatic recombination
with other antibodies.

Answer 64

all 4 parts labeled ‘A’

Question 65

The antibody shown below can help your body “fight” against
pathogens in all of the following ways EXCEPT . . .
A. neutralization of toxins
B. immobilization of bacteria
C. activation of ADCC
D. agglutination of viruses
E. interfering with bacterial
adhesion to surfaces

Answer 65

activation of ADCC

Question 66

How are T cells involved in antibody production?
A. They aren’t - antibodies are produced by B cells without any help from T cells.
B. Cytokines from TH cells cause proliferation and differentiation of B cells into plasma cells.
C. T cells present the antigen that B cells recognize to begin secretion of antibodies.
D. TC cells provide the “second signal” that tells B cells they have found a foreign antigen.
E. Binding of both a B cell and a T cell to the same antigen results in B cell anergy

Answer 66

Cytokines from TH cells cause proliferation and differentiation of B cells into plasma cells.

Question 67

When does a B cell undergo the genetic switch to begin producing IgG instead of IgM?
A. Never – the switch allows B cells to begin producing IgM instead of IgG.
B. before you’re born
C. as soon as the B cell binds to a pathogen
D. only after a second infection with the same pathogen
E. several days after the initial infection with a pathogen

Answer 67

several days after the initial infection with a pathogen

Question 68

What happens during the process called “clonal deletion”?
A. B cells that have bound to an antigen turn into plasma cells
B. Variable genes are joined to diversity genes by joining segments to expand antibody
diversity.
C. B cells that have bound to a repeating antigen release surface receptors as antibodies
D. B cells apoptose if their receptors recognize proteins present in bone marrow
E. B cells that fail to recognize a T-cell receptor lose their ability to be activated.

Answer 68

B cells apoptose if their receptors recognize proteins present in bone marrow

Question 69

Which of the following statements about antibody types is TRUE?
A. Most B-cells produce IgG as soon as they detect an infection.
B. IgA can cross the placenta to protect the baby for a few months after birth.
C. IgE is produced by class switching of the genes that encode the Fab part of IgM
D. The most effective antibody for agglutinating antigens is IgM.
E. The role of IgD is not clear, but it is involved in the allergic response.

Answer 69

The most effective antibody for agglutinating antigens is IgM.

Question 70

Which of the following steps occurs during the immune response to BOTH polysaccharide
vaccines AND protein-conjugate vaccines?
A. B cells engulf the vaccine antigen into an endocytic vesicle
B. B cell receptors bind to polysaccharide components of vaccine antigens
C. T cell receptors interact with the vaccine antigen presented on MHC-II
D. Cytokines induce the formation of plasma cells and B memory cells
E. Vaccine antigens are engulfed by macrophages or dendritic cells

Answer 70

B cell receptors bind to polysaccharide components of vaccine antigens

Question 71

Which of the following B cells would become anergic?
A. A B-cell that has a TH cell bound to its MHC
B. A B-cell that has not bound to any antigen
C. A B-cell that has a macrophage bound to its TLR
D. A B-cell that fails to bind to an antigen during development in bone marrow
E. A B-cell that is displaying an antigen to which no T-cell has bound

Answer 71

A B-cell that is displaying an antigen to which no T-cell has bound

Question 72

What is meant by the abbreviation ADCC?
A. Opsonization of a bacterium to enhance phagocytosis
B. Aggregation of bacterial cells to enhance phagocytosis
C. Blocking viral spike glycoproteins from binding to host cell receptors
D. Activating the classical complement pathway to destroy a pathogen
E. Tagging a cell so that NK cells bind to and destroy it

Answer 72

Tagging a cell so that NK cells bind to and destroy it

Question 73

Which of the following antibody types is correctly matched with a feature of that antibody?
A. IgM – only Ig produced in response to T-independent antigens
B. IgG – first Ig produced in response to an infection
C. IgD – FC part dimerizes to allow additional agglutination sites
D. IgA – can cross placenta to protect developing fetus
E. IgE – long half life allows long-term protection from circulating pathogens

Answer 73

IgM – only Ig produced in response to T-independent antigens

Question 74

Why does a second exposure to the same pathogen usually result in a much stronger immune
response against it?
A. Macrophages retain a memory of the pathogen and phagocytose it more effectively.
B. Antibodies produced during the first infection can remain in the body for years.
C. When a second infection occurs, Bmemory cells produce IgG without class switching.
D. When a second infection occurs, T cells can be directly stimulated by macrophages
without a B cell intermediate.
E. During a second infection, Bmemory cells can be produced without TH cell involvement.

Answer 74

When a second infection occurs, Bmemory cells produce IgG without class switching.

Question 75

What happens if you are exposed to an antigen but none of your circulating B cells has receptors
that recognize it?
A. You can produce new B cell receptors that may recognize this antigen.
B. Your antibodies will still recognize it, even though your B cells don’t.
C. You should be vaccinated against it, because you will have no immunity against it.
D. You will never be able to mount a humoral immune response against it.
E. New B cells can be released from your bone marrow that may recognize it, even
though no circulating B cells do.

Answer 75

New B cells can be released from your bone marrow that may recognize it, even
though no circulating B cells do.

Question 76

Which of the following is one way our immune system avoids producing antibodies that recognize
self antigens?
A. Somatic recombination is blocked if it produces self-recognizing B cells.
B. B cells become anergic if they are not also stimulated by TH cells.
C. B cells that fail to also bind TH cells in bone marrow apoptose.
D. A B cell binds to MHC-II, which only displays foreign antigens.
E. Such antibodies are produced, but they are opsonized and phagocytosed.

Answer 76

B cells become anergic if they are not also stimulated by TH cells.

Question 77

You are working in pharmaceutical research, and you want to make a vaccine against a bacterial
polysaccharide slime layer. You know that you will need to make a conjugated vaccine. Which of the
following is true about such a vaccine?
A. The conjugated protein may be the antigen that is displayed on a B cell’s MHC-II.
B. A T cell must recognize the polysaccharide part of the vaccine for it to work.
C. The conjugated protein allows the vaccine to bind to more than one B cell receptor at
the same time.
D. Only the polysaccharide component of the vaccine will be endocytosed by the B cell.
E. The conjugate protein must be from the same pathogen as the polysaccharide.

Answer 77

The conjugated protein may be the antigen that is displayed on a B cell’s MHC-II.

Question 78

How can IgG prevent a viral infection?
A. It can induce ADCC against the virus.
B. It can stop the synthesis of viral DNA or RNA.
C. It can immobilize the virus in the bloodstream.
D. It can neutralize viral binding to host receptors.
E. It can direct the insertion of a membrane attack complex into the viral capsid.

Answer 78

It can neutralize viral binding to host receptors.

Question 79

In DiGeorge’s Syndrome, the patient is born without a thymus. Such a patient obviously lacks
some of his immune system. Which of the following best represents his antibody titer after initial and
booster vaccination?

Answer 79

graph A

Question 80

In a T-dependent B cell response . . .
A. multiple B cell receptors are crosslinked by antigen
B. a B cell receptor must interact with a T cell receptor
C. a B cell must endocytose an antigen and display it on MHC-II
D. a T cell receptor must bind to CD8 on the B cell surface
E. somatic recombination occurs, but not clonal selection

Answer 80

a B cell must endocytose an antigen and display it on MHC-II

Question 81

Which of the following is correctly associated with a B cell that has become anergic?
A. Class switching is reversed so that IgG becomes IgM.
B. The B cell turns into a less active plasma cell.
C. The B cell begins to replicate uncontrollably.
D. An oxidative burst from the B cell releases energy.
E. The B cell displays an antigen that no T cell recognizes.

Answer 81

The B cell displays an antigen that no T cell recognizes.

Question 82

What is the main function of TC cells in the immune system?
A. to activate PMNs
B. to activate TH cells
C. to activate B cells
D. to initiate the complement system
E. to release perforin and granzymes

Answer 82

to release perforin and granzymes

Question 83

What happens when an effector TC cell binds to an antigen on an epithelial cell’s MHC1?
A. The TC cell kills the epithelial cell.
B. The TC cell recruits B cells to the site of the infection.
C. The TC cell releases cytokines that activate TH cells.
D. The TC cell becomes anergic.
E. The epithelial cell produces cytokines to activate the TC cell.

Answer 83

The TC cell kills the epithelial cell.

Question 84

Which of the following does NOT happen once TH cells have become activated?
A. The TH cells secrete cytokines
B. The TH cells activate macrophages
C. The TH cells activate B cells
D. The TH cells produce MHC2 on their surface
E. The TH cells stimulate themselves to divide and differentiate into memory cells.

Answer 84

The TH cells produce MHC2 on their surface

Question 85

Immune tolerance in T cells involves positive selection. What does that mean?
A. T cells are only released if their MHC1 recognizes antibodies in the thymus.
B. T cells are only released if their TCR recognizes thymus cells’ MHC1.
C. T cells are only released if their MHC2 recognizes macrophages in the thymus.
D. T cells are not released if their antibodies recognize antigen in the thymus.
E. T cells are not released if their TCR recognize thymus cells’ MHC2.

Answer 85

T cells are only released if their TCR recognizes thymus cells’ MHC1.

Question 86

What is the difference between TH and TC cells?
A. TH cells have MHC1 on their surface, TC have MHC2
B. TH cells recognize antigens, TC cells recognize antibodies.
C. TH cells secrete cytokines, TC cells secrete perforin.
D. TC cells need two signals for them to become “effector” T cells; TH only need one.
E. TC cells bind only to APCs, TH can bind to any other cell.

Answer 86

TH cells secrete cytokines, TC cells secrete perforin.

Question 87

If a TH cell binds to an MHC on “cell A” that is presenting an antigen, but binds to nothing else,
what happens?
A. The body assumes cell A is infected; TH releases perforins and granzymes.
B. The body assumes cell A is infected; TH activates nearby B cells.
C. The T cell is engulfed by the MHC on cell A.
D. The body assumes this is a mistake; the TH cell becomes unresponsive.
E. The TH cell remains bound to cell A and attracts antibodies in case an infection is nearby.

Answer 87

The body assumes this is a mistake; the TH cell becomes unresponsive.

Question 88

Effector TH cells can do all of the following EXCEPT . . .
A. Phagocytize nearby bacteria
B. Activate TC cells that have bound to an MHC1-Antigen complex
C. Induce B cell clonal expansion
D. Induce the formation of memory T cells
E. Cause macrophages to become more potent

Answer 88

Phagocytize nearby bacteria

Question 89

What is the most correct statement about the selection process T cells must undergo before they are
released to the blood?
A. V-D-J combinations do not occur if they would produce TCRs against self antigens.
B. TCRs must recognize self MHCs, but must not recognize antigens on the MHCs.
C. Recognizing any circulating antigen causes T cells to become anergic.
D. Recognizing any antigens in bone marrow causes T cells to apoptose.
E. T cells fail to multiply in the thymus unless they recognize a self antigen on an MHC1

Answer 89

TCRs must recognize self MHCs, but must not recognize antigens on the MHCs.

Question 90

What type of cells do NK cells kill?
A. any bacteria with PMPs (or other recognition signals) exposed
B. B cells with B cell receptors whose Fab parts the NK cells recognize
C. TC cells without B7 on their surface
D. T cells that have phagocytized bacteria
E. any cells without MHC1 (or its equivalent) on their surface

Answer 90

any cells without MHC1 (or its equivalent) on their surface

Question 91

What is the role of the B7 protein in the immune response?
A. It is a receptor on macrophages that recognizes pathogens.
B. It is produced by infected macrophages to help stimulate T cells.
C. It is a type of antibody produced by effector B cells.
D. It is a protein on TC cells that allows them to bind to TH cells.
E. It is secreted by TH cells to stimulate B cell clonal expansion and differentiation.

Answer 91

It is produced by infected macrophages to help stimulate T cells.

Question 92

A TH cell is secreting interleukin-2 (IL-2). This means that . . .
A. it will soon undergo apoptosis.
B. it will now be able to ingest bacteria that bind to its TLR receptors.
C. it is infected by a virus and has sensed the presence of double-stranded RNA.
D. nearby TC cells will become activated once they bind to an antigen-MHC1 complex.
E. an autoimmune disease is allowing the TH cell to recognize a self antigen.

Answer 92

nearby TC cells will become activated once they bind to an antigen-MHC1 complex.

Question 93

How do activated macrophages differ from non-activated (naïve) macrophages?
A. They contain more lysosomes.
B. They can activate B cells.
C. They can bind to TH cells.
D. They produce more cytokines.
E. They have contacted a TC cell to become “activated.”

Answer 93

they contain more lysosomes.

Question 94

What is the role of NK cells in the immune response?
A. They can activate the complement system
B. They destroy TC cells that recognize self antigens
C. They secrete cytokines that activate B cells
D. They are responsible for production of T-independent antibodies
E. They participate in antibody-dependent cellular cytotoxicity

Answer 94

They participate in antibody-dependent cellular cytotoxicity

Question 95

What is a major difference between TH and TC cells?
A. TC can bind to almost any infected cell; TH only bind infected antigen presenting cells
B. TC mostly secrete cytokines; TH secrete histamine
C. Effector TH cells induce apoptosis; effector TC cells induce humoral immunity
D. TH cells produce B7, but TC cells produce interleukin-2
E. TH cells undergo clonal deletion; TC undergo clonal expansion

Answer 95

TC can bind to almost any infected cell; TH only bind infected antigen presenting cells

Question 96

Which of the following correctly refers to the second signal that is required for T cell activation?
A. It is secreted by a B cell that has already bound antigen.
B. It is a protein that attaches to MHC-II.
C. When T cells bind it, they become more energized, anergic T cells.
D. It is a cytokine that enhances the antibody-producing ability of T cells.
E. It is only produced when a pathogen is recognized by the immune system.

Answer 96

It is only produced when a pathogen is recognized by the immune system.

Question 97

Upon receipt of cytokine signals from effector TH cells, macrophages . . .
A. undergo class switching and begin to secrete antibodies.
B. become antigen-presenting cells.
C. differentiate into long-lived memory macrophages.
D. produce a more potent oxidative burst that includes nitric oxide.
E. begin recruiting the membrane attack complex to kill invading bacteria.

Answer 97

produce a more potent oxidative burst that includes nitric oxide.

Question 98

What do TH and TC cells have in common?
A. They can both engulf bacterial PMPs.
B. They can both bind to MHC1 to stimulate B cells.
C. Both can secrete perforin to induce apoptosis in infected cells.
D. Both produce the signaling molecule B7.
E. Both need an infection-specific “second signal” to avoid becoming anergic.

Answer 98

Both need an infection-specific “second signal” to avoid becoming anergic.

Question 99

Humans with the mutation IL<tm1hor> fail to produce interleukin-2. Which of the following
would you expect to be a direct result of this mutation?
A. B cell function would be impaired.
B. TC cells could only be activated by binding to infected APCs.
C. T cells that recognize self-antigens would remain in the body.
D. T cells would be unable to produce antibodies unless stimulated directly by B cells.
E. TH cells could never mature and differentiate into TC cells.</tm1hor>

Answer 99

TC cells could only be activated by binding to infected APCs.

Question 100

What advantage does a protein conjugate vaccine (PCV) have over a polysaccharide subunit
vaccine (psv)?
A. The PCV induces cellular as well as humoral immunity.
B. The PCV allows TH cells to produce antibodies as well as B cells.
C. The PCV is essentially a “double” vaccine, with broader coverage than the psv.
D. The PCV induces the formation of memory B cells.
E. The PCV produces activated macrophages much more frequently than the psv.

Answer 100

The PCV induces the formation of memory B cells.

Question 101

Which T cell type is correctly matched with a function?
A. TH cells - Have surface receptors that recognize a pathogen
B. Tregulatory cells - Decrease the intensity of the cellular immune response
C. TC cells - Secrete interleukin-2 to allow other T cells to divide
D. Tmemory cells - Produce IgG immediately upon infection
E. TH cells - Bind to the FC part of antibodies to cause ADCC

Answer 101

Tregulatory cells - Decrease the intensity of the cellular immune response

Question 102

What is wrong with the picture at the right?
A. TC cells do not bind to APCs.
B. APCs have MHC-II, not MHC-I.
C. NK cells release the perforins, not
TC cells.
D. The target of the effector TC cell
should be a bacterium.
E. The TC cell shown in the drawing
should become anergic, not activated.

Answer 102

The TC cell shown in the drawing
should become anergic, not activated.

Question 103

During pre-clinical testing, a certain pharmaceutical drug is found to stimulate the production of
interleukin-2 (IL-2) in human cell cultures. This finding is . . .
A. good, because IL-2 allows V-D-J joining so that antibodies can be produced.
B. bad, because IL-2 is involved in the Type II hypersensitivity response.
C. good, because IL-2 is an important anti-viral defense.
D. bad, because producing IL-2 without an infection will overstimulate TC cells.
E. good, because IL-2 can act like a hapten to induce cellular immunity.

Answer 103

bad, because producing IL-2 without an infection will overstimulate TC cells.

Question 104

To what do NK cells bind?
A. MHC-II on APCs
B. MHC-II on TC cells
C. The circled parts of the antibody shown here :
D. PAMPs on the surface of bacterial cells
E. “Killer receptors” on any eukaryotic cell

Answer 104

“Killer receptors” on any eukaryotic cell

Question 105

The protein called B7 is produced by ________ to ensure that an immune response is only
produced in response to the presence of a pathogen.
A. TH cells
B. B cells
C. dendritic cells
D. bacteria
E. all cells with nuclei

Answer 105

dendritic cells

Question 106

We mentioned in class that a lot of money is being spent to develop a protein-conjugate vaccine
that recognizes 13 of the 80 different varieties of Streptococcus pneumoniae. But there is already a
polysaccharide vaccine that recognizes 23 of the 80 varieties. What is the advantage of the new
vaccine?
A. An epitope of the conjugated protein can be recognized by TH cells.
B. The protein binds to more B cell receptors than the polysaccharide does.
C. The protein is a better PAMP than the polysaccharide is.
D. NK cells recognize the protein better than they do the polysaccharide.
E. There is actually more immune tolerance if fewer varieties of S. pneumoniae are
recognized.

Answer 106

An epitope of the conjugated protein can be recognized by TH cells.

Question 107

What type of cells do NK cells kill?
A. any cell with MHC-I on its surface
B. T cells that have recognized “self” antigens during development
C. B cells without B7 on their surface
D. Macrophages that have phagocytized bacteria
E. mainly cancer cells and virally-infected cells

Answer 107

mainly cancer cells and virally-infected cells

Question 108

Which of the lines in the following table is INCORRECT?
TH cells TC cells
A. surface antigens CD4, CD28 CD8, CD28
B. binds to . . . MHC-II MHC-I
C. presents antigens from cytoplasm cytoplasm and phagolysosome
D. secretes interleukins perforins
E. antiviral role stimulatory kills infected cells

Answer 108

presents antigens from cytoplasm cytoplasm and phagolysosome

Question 109

. What is the role of Treg cells in the immune response?
A. They produce the cytokine IL-10 to reduce the effectiveness of TH and TC cells.
B. They produce the cytokine IL-2 to stimulate TC cell differentiation.
C. They regulate B-cell clonal expansion in the absence of nearby macrophages.
D. They regulate the interaction between TC cells and NK cells.
E. They secrete regulatory antibodies that limit the body’s autoimmune responses.

Answer 109

They produce the cytokine IL-10 to reduce the effectiveness of TH and TC cells.

Question 110

How do NK cells function?
A. They induce apoptosis in any cell to which they bind.
B. They kill cells to which they bind unless inhibitory signals outweigh stimulatory ones.
C. They bind to antibodies and enhance the ability of antibodies to kill foreign cells.
D. They interact with B7 and CD28 to stimulate APCs to kill bacteria.
E. They stimulate complement activation by binding to the Fc part of an antibody.

Answer 110

They kill cells to which they bind unless inhibitory signals outweigh stimulatory ones.

Question 111

Which part of this T cell receptor is produced only AFTER the T cell
has bound an antigen?
A. The part labeled “A”
B. The parts labeled “B”
C. The entire T cell receptor
D. None of it. It is all produced BEFORE antigen binding.
E. T cells don’t bind antigens; only antibodies do that.

Answer 111

None of it. It is all produced BEFORE antigen binding.

Question 112

The following table tries to define the differences between TH and TC cells, but it gets a lot of
things wrong. Which line in the table is correct?
TH cells TC cells
A. T cell binds to . . . APCs only any cell type
B. T cell stimulates . . . IgG production IgA production
C. T cell surface protein . . . CD28 B7 (CD80)
D. T cell presents antigens on . . . MHC-II MHC-I
E. T cell recognizes . . . foreign antigens self antigens

Answer 112

T cell binds to . . . APCs only any cell type

Question 113

Which of the following is true about T cells that recognize self antigens?
A. They never form.
B. They are responsible for Type III hypersensitivity reactions.
C. They can activate macrophages even in the absence of protein B7.
D. They form because V-J joining is random, but they apoptose in the thymus.
E. The second signal that activates them is antibody binding to MHC-II on their surface.

Answer 113

They form because V-J joining is random, but they apoptose in the thymus.

Question 114

Which of the following cell types is LEAST likely to be killed by NK cells?
A. Cells in your body that are infected by viruses
B. Cells in your body that are overproducing MHC-I
C. Cells in your body that have a hapten stuck to their surface
D. Bacterial cells that have invaded your body
E. Cells in your body that have been transformed to become tumor cells

Answer 114

Cells in your body that are overproducing MHC-I

Question 115

What is meant by “cellular” immunity?
A. Any immune response involving cells (B cells, Dendritic cells, T cells, etc.)
B. Immunity related specifically to T cells or NK cells.
C. Any immune response that requires cell division.
D. Immunity related specifically to the presence of phagocytes.
E. An overactive immune response also known as a Type IV hypersensitivity.

Answer 115

Immunity related specifically to T cells or NK cells.

Question 116

Which of the following is a type of cell involved in the immune response?
A. B cell receptor
B. interleukin-2
C. macrophage
D. PAMP
E. CD4

Answer 116

macrophage

Question 117

How do Treg cells differ from TH cells?
A. When Treg cells bind B7, they engulf and destroy it.
B. Treg cells secrete apoptotic cytokines that kill nearby cells.
C. Treg cells phagocytose and digest pathogens in the gut.
D. Treg cells recognize endogenous antigens on MHC-I.
E. Treg cells recognize self antigens in addition to foreign ones.

Answer 117

When Treg cells bind B7, they engulf and destroy it.

Question 118

How do Treg cells differ from TH cells?
A. When Treg cells bind B7, they engulf and destroy it.
B. Treg cells secrete apoptotic cytokines that kill nearby cells.
C. Treg cells phagocytose and digest pathogens in the gut.
D. Treg cells recognize endogenous antigens on MHC-I.
E. Treg cells recognize self antigens in addition to foreign ones.

Answer 118

When Treg cells bind B7, they engulf and destroy it.

Question 119

Which of the following can be killed by NK cells?
A. Dendritic cells, but only after they have engulfed a pathogen
B. Only foreign parasites circulating in the blood
C. Only tumor cells
D. Any cell that lacks MHC-I or has antibodies bound to it
E. Any lymphocyte that is displaying a foreign antigen

Answer 119

Any cell that lacks MHC-I or has antibodies bound to it

Question 120

Giving a shot of tetanus toxoid antibodies after a patient has been infected with tetanus is an
example of. . .
A. active, artificial immunity
B. passive, artificial immunity
C. active, natural immunity
D. passive, natural immunity
E. a conjugate vaccine

Answer 120

passive, artificial immunity

Question 121

Which of the following could be a possible interpretation of the
agglutination test shown in circle A?
A. The antibodies recognize the organism’s surface antigens.
B. The antibodies recognize soluble antigens in the serum.
C. The antibodies are present in large excess compared to the antigens
D. The antibodies do not recognize any antigens in the sample.
E. Sample A was incubated with antibody B.

Answer 121

The antibodies recognize soluble antigens in the serum.

Question 122

A major advantage of using inactivated vaccines rather than live vaccines is that . . .
A. inactivated vaccines produce a longer immune memory
B. inactivated vaccines stimulate B cells and T cells equally
C. inactivated vaccines can be given to immunocompromised patients
D. inactivated vaccines are easier to administer to a patient
E. live vaccines require an adjuvant to avoid a serious anaphylactic response

Answer 122

inactivated vaccines can be given to immunocompromised patients

Question 123

The current vaccine against Streptococcal pneumonia is produced by attaching the capsule
polysaccharide from S. pneumoniae to a protein and injecting it into the patient. What purpose does the
protein serve?
A. It is recognized by TH cells, allowing a stronger B cell response to the vaccine.
B. It is an adjuvant that boosts the ability of macrophages to engulf the vaccine.
C. It is a platform to make the vaccine antigen easier to manipulate in the lab.
D. It allows B cells to respond to the vaccine without the need for T cell involvement.
E. It allows the body to produce antibodies against more diverse antigens.

Answer 123

It is recognized by TH cells, allowing a stronger B cell response to the vaccine.

Question 124

What is the vaccine in question #4 called?
A. A live attenuated vaccine
B. A toxoid vaccine
C. A subunit conjugate vaccine
D. An oral recombinant vaccine
E. An artificial passive vaccine

Answer 124

A subunit conjugate vaccine

Question 125

A patient is suspected of having been infected with Norovirus, which is an acute viral illness. The
patient’s blood serum is tested by direct ELISA, and tests positive at a titer of 1:16. This compares
with a pre-immune serum testing positive at a dilution of 1:8. Interpret the result.
A. The patient has been infected with Norovirus.
B. The patient is currently infected with Norovirus.
C. The patient has not been infected with Norovirus.
D. The patient currently has no circulating antigens from Norovirus in his blood.
E. The test is not valid - an indirect ELISA should have been used for this.

Answer 125

The test is not valid - an indirect ELISA should have been used for this.

Question 126

A patient is injected with antibodies against tetanus toxin. What is the purpose of this injection?
A. To induce a T-dependent response in the patient rather than a T-independent response
B. To activate the patient’s memory B cells, thereby boosting antibody titer
C. To bind and immediately inactivate tetanus toxin in a life-threatening intoxication
D. To prevent the patient from making IgE against tetanus toxin
E. To enhance the herd immunity level of the community in which the patient lives

Answer 126

To bind and immediately inactivate tetanus toxin in a life-threatening intoxication

Question 127

Which of the following is generally the LEAST effective type of vaccine?
A. Live attenuated vaccine
B. Protein conjugate vaccine
C. Subunit vaccine
D. Polysaccharide vaccine
E. Whole-cell inactivated vaccine

Answer 127

Polysaccharide vaccine

Question 128

A promising new vaccine technology involves injecting DNA from a pathogen into a patient’s cells.
How does such a vaccine work?
A. The patient’s B cells are activated more strongly than with a normal vaccine.
B. The patient’s MHCs display translated foreign proteins, activating cellular immunity.
C. The patient makes antibodies against the pathogen’s DNA.
D. The DNA is used to reproduce the pathogen inside the patient, activating the same
immune response as a direct infection.
E. The DNA activates IgA selectively, providing immunity against respiratory pathogens

Answer 128

The patient’s MHCs display translated foreign proteins, activating cellular immunity.

Question 129

What do precipitin and agglutination tests have in common?
A. Both require that the antibodies have at least two antigen binding sites.
B. A positive test is indicated by a white line between the antigen and antibody spots.
C. Both require diffusion of antigen and antibody through a gel.
D. Both involve labeled secondary antibodies.
E. Both involve electrophoretic separation of the antigens.

Answer 129

Both require that the antibodies have at least two antigen binding sites.

Question 130

How do live attenuated vaccines produce a strong immune response in a vaccinated host?
A. They can be conjugated to proteins.
B. They are added with an adjuvant, alum.
C. The most highly antigenic subunits can be combined in the vaccine.
D. They can replicate in the host and persist for a long time.
E. They activate B cells, which produce a stronger response than T cells.

Answer 130

They can replicate in the host and persist for a long time.

Question 131

The bacterium Legionella pneumophila causes an acute bacterial pneumonia with an incubation
period of 3 days (not one we discussed in class). It can often be diagnosed only by serological tests. A
patient with pneumonia arrives at a Dr’s office for various tests, including a titer for anti-Legionella
IgG. The titer is 1:32. No diagnosis is made, but the patient eventually recovers. The Dr still wants to
know what caused the illness, though, so she runs another IgG titer. If the patient’s pneumonia had
been caused by Legionella, which of the following antibody titers might the Dr expect to find?
A. 1:256
B. 1:64
C. 1:32
D. 1:8
E. zero, if all the bacteria are gone from the patient’s body

Answer 131

1:256

Question 132

What test would be best for the IgG titers mentioned in question #13?
A. a precipitin test
B. indirect immunoelectrophoresis
C. a direct ELISA test
D. an indirect ELISA test
E. a direct fluorescent antibody test

Answer 132

an indirect ELISA test

Question 133

A patient is tested for Hepatitis E by Western Blot. The proteins in the patient’s
blood plasma are separated by electrophoresis as shown in panel A. After transfer to
filter paper, anti-HepE antibodies are added, followed by secondary antibodies (panel
B). What can be concluded from the results?
A. The patient is not now infected with HepE, but has been in the past.
B. Only two bands show up on the blot. The patient does not have HepE.
C. The patient does not have HepE, but does have a secondary infection.
D. The anti-HepE antibody was a monoclonal antibody.
E. The patient is currently infected with HepE.

Answer 133

The patient is not now infected with HepE, but has been in the past.

Question 134

In a trial for a vaccine against a respiratory illness that is spread person-to-person, all 1800 adults
in a Swiss village were vaccinated with a live attenuated vaccine. 150 of the 1800 people in the trial
failed to produce IgG in response to the vaccine, yet they still didn’t get sick. Why not?
A. They were protected by IgM.
B. They were protected by natural, passive immunity.
C. They had exceptionally strong immune systems.
D. They were protected by herd immunity.
E. Their dendritic cells could not recognize the pathogen’s PMP.

Answer 134

They were protected by herd immunity.

Question 135

How can an antibody’s titer be determined most easily?
A. by observing its reaction with an antigen
B. by diluting it and plating it on a Kirby-Bauer plate
C. by filtering it and adding a dye to the filter
D. by isolating it from blood and examining it by electron microscopy
E. by adding it to a bacterial culture and watching the bacteria lyse

Answer 135

by observing its reaction with an antigen

Question 136

A patient is suspected of having been infected with an acute viral illness (AVI). The patient’s
blood serum is tested for antibodies, and tests positive at a titer of 1:16. This compares with a
preimmune serum testing positive at a titer of 1:8. Interpret the result.
A. The patient has been infected with AVI.
B. The patient is currently infected with AVI.
C. The patient has not been infected with AVI.
D. The patient currently has no circulating antigens from AVI in his blood.
E. The test is not valid. The preimmune control test should be negative.

Answer 136

The patient is currently infected with AVI.

Question 137

In the precipitin test shown by this picture, well C contains IgG against
diphtheria toxin. Which of the following must be true?
A. Well A contains diphtheria toxin.
B. Well B contains diphtheria toxin.
C. The white line between wells A and C contains aggregated clumps of cells.
D. Fluorescent antibodies have been added to well C.
E. This is a type of direct ELISA.

Answer 137

Well A contains diphtheria toxin.

Question 138

Injection of a patient with tetanus immune globulin is an example of . . .
A. artificial, active immunity
B. artificial, passive immunity
C. natural, active immunity
D. natural, passive immunity
E. desensitization to overcome a Type I hypersensitivity

Answer 138

artificial, passive immunity

Question 139

Which of the following vaccine types produces the strongest IgA response?
A. Toxoid vaccine
B. Live, injected vaccine
C. Formalin-killed vaccine
D. Recombinant, edible vaccine
E. DNA-based vaccine

Answer 139

Recombinant, edible vaccine

Question 140

The test shown below . . .
A. is an example of an agglutination test
B. can determine which bacterial surface molecules to use in a subunit vaccine
C. is a typical Western Blot
D. could represent a negative result (a patient who is not infected with a particular bacterium)
E. is most likely used to compare a pre-immune serum to a convalescent serum

Answer 140

can determine which bacterial surface molecules to use in a subunit vaccine

Question 141

Which of the following is true for a direct ELISA, but not for an indirect ELISA?
A. To begin the test, known antibodies are bound to the bottom of a microtiter well.
B. The test uses an enzyme reaction to visualize antibodies.
C. Anti-FC secondary antibodies are used to detect the primary antibodies.
D. The test can be used to detect a latent infection.
E. The test can be made more sensitive by conjugating latex beads to the known antigen.

Answer 141

To begin the test, known antibodies are bound to the bottom of a microtiter well.

Question 142

An example of passive immunity is . . .
A. getting a DTaP booster shot after you have had the initial vaccine
B. getting injected with blood serum from a patient who formerly had diphtheria
C. not getting measles because most of the people around you have been vaccinated
D. using the nasal “Flu-Mist” spray rather than getting a flu shot
E. getting injected with an allergen to help you overcome a childhood allergy

Answer 142

getting injected with blood serum from a patient who formerly had diphtheria

Question 143

One advantage of a live attenuated vaccine (LAV) over an inactivated subunit vaccine (ISV) is . . .
A. the LAV is more stable under harsh environmental conditions
B. the LAV is safe to use in people who are taking cyclosporin or basiliximab
C. memory T cells are produced in response to the LAV
D. an adjuvant can be used with the LAV to improve B-cell response
E. the LAV is quicker to make; the ISV requires generations of growth outside a host

Answer 143

memory T cells are produced in response to the LAV

Question 144

Pharmaceutical companies are finally beginning to develop DNA-based vaccines. These vaccines
work by causing a vaccinated person to . . .
A. make antibodies against a pathogen’s DNA
B. produce one of a pathogen’s proteins in order to elicit a T cell response
C. be protected against pathogens into which the person’s DNA has been cloned
D. develop immune tolerance to common antigens, thereby preventing allergies
E. produce a monoclonal antibody rather than the less effective polyclonal kind

Answer 144

produce one of a pathogen’s proteins in order to elicit a T cell response

Question 145

A patient is suspected of having been infected with Norovirus, which is an acute viral illness. The
patient’s blood serum is tested by indirect ELISA, and tests positive with a titer of 1:64. This compares
with a pre-immune serum testing positive with a titer of 1:4. Interpret the result.
A. The patient has been infected with Norovirus.
B. The patient is currently infected with Norovirus.
C. The patient has not been infected with Norovirus.
D. There is a mistake – a direct ELISA should have been used for this.
E. There is a mistake – the two titers have been switched.

Answer 145

The patient has been infected with Norovirus.

Question 146

You are a physician examining the blood test of a couple planning to get
married. At the right is an agglutination test performed with anti-Rh antibodies.
This particular couple belongs to a religion that does not accept transfusion or
injection with human blood products. What would you advise them?
A. There is a blood mismatch. They should not get married.
B. The incompatibility can be overcome by an injection that does not
involve blood products.
C. The incompatibility will limit them to having only one child.
D. There is a blood mismatch, but it won’t cause any problem having children.
E. There is no blood mismatch.

Answer 146

There is a blood mismatch, but it won’t cause any problem having children.

Question 147

Are we concerned about herd immunity levels when using passive immunizations? Why or
why not?
A. No. Passive immunization is too temporary for herd immunity to be important.
B. Yes. If too few people are vaccinated, a disease can spread in a community.
C. No. Herd immunity only applies to natural infections, not immunizations.
D. Yes. If everyone is passively immunized, no one will get the disease.
E. Passive immunity is a natural event; there is no such thing as “passive immunization.”

Answer 147

No. Passive immunization is too temporary for herd immunity to be important.

Question 148

Which of the following statements about live attenuated vaccines (LAV) and inactivated
vaccines (INV) is correct?
A. LAV contain the actual disease agent, which can induce a strong immune response.
B. INV fail to induce B-cell responses, and so very low antibody titers are produced.
C. LAV must always be given with adjuvants to maximize the humoral response.
D. INV allow a patient to translate antigens from injected pathogen DNA.
E. LAV can be either orally administered or injected, whereas INV must be injected.

Answer 148

LAV can be either orally administered or injected, whereas INV must be injected.

Question 149

To what can a Western blot be most accurately compared? Why?
A. to a direct ELISA since both use secondary antibodies that recognize IgG Fc
B. to a precipitin test since both involve agglutination of antigens
C. to immunoelectrophoresis, since both involve using antibodies to detect separated antigens
D. to a direct fluorescent antibody test, since both involve transfer to filter paper membranes
E. to an indirect ELISA since both require antibodies to be bound to a solid support

Answer 149

to immunoelectrophoresis, since both involve using antibodies to detect separated antigens

Question 150

Two examples of passive immunity are . . .
A. IgA in breast milk and IgA produced in response to a type of flu vaccine
B. live attenuated vaccines and inactivated vaccines
C. oral vaccines and injected vaccines
D. the two components of a tetanus shot
E. Fetal IgG protection and Diphtheria immune globulin

Answer 150

Fetal IgG protection and Diphtheria immune globulin

Question 151

What is an adjuvant?
A. A toxin that has been inactivated by formaldehyde crosslinking
B. A type of vaccine in which DNA is injected into your cells
C. A substance in some vaccines that helps to elicit a cellular immune response
D. A substance that must be added to live vaccines to attenuate them
E. A young lymphoid stem cell before it becomes either a TH or a TC cell

Answer 151

A substance in some vaccines that helps to elicit a cellular immune response

Question 152

Which of the following tests DOES NOT use two antibodies, one labeled and one unlabeled?
A. Western Blot (Immunoblot)
B. Direct ELISA test
C. Indirect ELISA test
D. Indirect fluorescent antibody test
E. Immunodiffusion test

Answer 152

Immunodiffusion test

Question 153

A friend of yours who knows you took Bio 221 is planning to invest in a company that says they
are working on an anti-cancer vaccine. The friend asks your advice about his investment. What would
you say to him?
A. This is a scam. Such vaccines are not possible, based on what we know about cancer cells.
B. It’s a DNA vaccine designed to boost your TC cell response to cancer-specific antigens
C. It involves microinjecting tumors with substances designed to boost NK cell response.
D. It’s a good idea, but it will only work for the few cancers that are caused by infectious
agents like viruses.
E. It probably tries to stimulate self-recognizing antibodies that can kill cancer cells.

Answer 153

It’s a DNA vaccine designed to boost your TC cell response to cancer-specific antigens

Question 154

Pharmacologists have learned that conjugated vaccines are much more effective than their
polysaccharide vaccine counterparts. What is so special about conjugated vaccines?
A. They cause a single B cell to produce multiple different antibodies.
B. They contain a protein epitope that blocks an antigen from binding to multiple B cell
receptors simultaneously.
C. A B cell exposed to such a vaccine can bind to two different antigens simultaneously.
D. Two different B cells must participate in the immune response, thereby producing
twice the antibodies.
E. If a B cell cannot recognize a particular antigen, a conjugate vaccine allows a T cell to
recognize it instead.

Answer 154

They contain a protein epitope that blocks an antigen from binding to multiple B cell
receptors simultaneously.

Question 155

Which of the following is an advantage of administering a vaccine for Typhoid fever orally?
A. It leads to the production of IgA, which protects the portal of entry for this infection.
B. It produces a stronger cellular immune response than injected vaccines would.
C. You can administered a killed vaccine orally without an adjuvant.
D. An oral vaccine can replicate in the body, but an injected one cannot.
E. The oral route allows a faster switch to IgG than the injected route.

Answer 155

It leads to the production of IgA, which protects the portal of entry for this infection.

Question 156

How do you know that a person has been exposed to a particular pathogen within the past year or
so?
A. You’d have to perform an immunoelectrophoresis test.
B. If the well of a direct ELISA microtiter plate turns red
C. If the person produces monoclonal antibodies against the pathogen
D. If an immunoprecipitate test performed with the patient’s serum looks like this:
E. If the person’s antibody titer against the pathogen, which was 1:8, is now 1:128

Answer 156

If the person’s antibody titer against the pathogen, which was 1:8, is now 1:128

Question 157

What is run on the gel if a Western blot is being used as a direct immunological test?
A. Antibodies from the patient’s serum
B. Known antibodies
C. Antigens from the patient’s serum
D. Known antigens
E. A Western blot can’t be run as a direct test.

Answer 157

Known antibodies

Question 158

Class switching in B cells from _______ to _______ is responsible for the allergic response.
A. IgG to IgM
B. IgA to IgG
C. IgM to IgE
D. IgE to IgG
E. MHC2 to MHC1

Answer 158

IgM to IgE

Question 159

Which of the following is NOT part of an allergic response?
A. A B-cell binds the allergen and is activated by a TH cell.
B. The B-cell turns into a plasma cell.
C. Circulating antibodies bind to mast cells.
D. Activated B cells bind allergen a second time.
E. Allergen binds simultaneously to at least two antibodies on mast cells.

Answer 159

Activated B cells bind allergen a second time.

Question 160

In rheumatoid arthritis, both B- and T-cells recognize the auto-antigen collagen, and circulating
antibodies are produced against collagen. Which of the following is caused by those antibodies?
A. They bind to mast cells and elicit a Type I hypersensitivity reaction.
B. They bind to collagen and are deposited as immune complexes in joints.
C. They bind to collagen and recruit NK cells to destroy collagen cells.
D. They also recognize heart muscle, and cause rheumatic fever.
E. They recruit TC cells and cause a Type IV hypersensitivity rash.

Answer 160

They bind to collagen and are deposited as immune complexes in joints.

Question 161

Bob has had tuberculosis. If a TB skin test is performed on Bob, what will happen?
A. He will show a red rash within a few minutes at the site where the test was performed.
B. He will show a red rash over his whole body within a few hours.
C. After a few days he will show a red rash at the site where the TB antigen was injected.
D. He will form immune complexes to the injected antigen.
E. Nothing, unless his TB is active at the time of the test.

Answer 161

After a few days he will show a red rash at the site where the TB antigen was injected.

Question 162

The most common immune disorder in the US is selective IgA deficiency. People who suffer from
this will be more likely to get ______________ than other people.
A. allergies
B. systemic lupus erythematosis
C. blood-borne illnesses
D. viral infections
E. respiratory and digestive illnesses

Answer 162

respiratory and digestive illnesses

Question 163

Which of the following describes a Type II hypersensitivity reaction?
A. IgE causes cytokine release from T-lymphocytes.
B. Excess IgG causes immune complexes to form.
C. The first exposure to an antigen elicits as severe a response as subsequent exposures.
D. IgG binds to a hapten on a cell, recruiting complement and NK cells.
E. Effector TH cells activate TC cells against the body’s own antigens.

Answer 163

IgG binds to a hapten on a cell, recruiting complement and NK cells.

Question 164

In the disease rheumatoid arthritis, a person makes antibodies against her own collagen. Antibodyantigen complexes form in the capillaries of joints, causing inflammation leading to arthritis. This is an
example of . . .
A. Type I hypersensitivity
B. Type II hypersensitivity
C. Type III hypersensitivity
D. Type IV hypersensitivity
E. an immunodeficiency disease

Answer 164

Type III hypersensitivity

Question 165

In the disease Lupus, autoantibodies are directed against
A. DNA
B. B cells
C. Epithelial cell receptors
D. The neurotransmitter acetylcholine
E. Almost anything you touch or eat.

Answer 165

DNA

Question 166

Inheritance of the immunodeficiency disease agammaglobulinemia results in the failure to produce
B cells. A patient with this disease would . . .
A. Be very susceptible to intracellular pathogens like Shigella
B. Never develop an acquired immune response
C. Be incapable of developing any type of hypersensitivity reaction
D. Be very susceptible to bacterial toxins
E. Be incapable of activating the complement system

Answer 166

Be very susceptible to bacterial toxins

Question 167

Some allergies can be overcome by injecting small amounts of the allergen repeatedly into the
patient. How does this work?
A. The allergen prevents the patient from making IgE, so no allergic response can occur.
B. The allergen activates cellular immunity, which counteracts the allergic response.
C. The allergen binds to the surface of mast cells, preventing IgE from binding.
D. Injected allergen forms smaller immune complexes, which are non-allergenic.
E. The patient produces IgG, which binds the allergen instead of the IgE on mast cells.

Answer 167

The patient produces IgG, which binds the allergen instead of the IgE on mast cells.

Question 168

In the disease lupus, your B cells recognize your own DNA, making antibodies that form antigenantibody complexes with DNA. This is an example of which type of hypersensitivity?
A. Type I
B. Type II
C. Type III
D. Type IV
E. It’s not a hypersensitivity reaction, but it causes DNA damage.

Answer 168

Type III

Question 169

During vaccine clinical trials, it was discovered that a vaccine antigen could bind to a receptor on
the patient’s epithelial cells. The vaccine development was cancelled. Why?
A. The vaccine might prevent the disease agent from being recognized by phagocytes.
B. The patient couldn’t make antibodies to this sort of antigen.
C. The vaccine antigen might activate a Type IV hypersensitivity reaction.
D. IgG bound to the vaccine antigen might direct ADCC against the patient’s own cells.
E. The patient’s TC cells might destroy the vaccine antigen, making it ineffective.

Answer 169

IgG bound to the vaccine antigen might direct ADCC against the patient’s own cells.

Question 170

Serious type IV hypersensitivity reactions are usually treated . . .
A. with anti-histamines
B. with immune globulin injections
C. by suppressing T cell response
D. by using one type of antibody to competitively inhibit another
E. by using cytokines to enhance the innate immune response

Answer 170

by suppressing T cell response

Question 171

What is a hapten?
A. It refers to the way the Fc portions of IgM are arranged.
B. It is a cluster of antibodies and antigens that triggers a type III hypersensitivity.
C. It is a small molecule that binds to a cell and triggers a type II hypersensitivity.
D. It can be injected into the blood to prevent a type I hypersensitivity.
E. It is a new type of conjugated vaccine that uses the DNA of the pathogen.

Answer 171

It is a small molecule that binds to a cell and triggers a type II hypersensitivity.

Question 172

A person who is allergic to pollen has small amounts of pollen injected under his skin. What is the
purpose of this?
A. It reduces the number of anti-pollen antibodies he makes.
B. It removes the memory T cells that recognize pollen antigens.
C. It reduces the affinity of his mast cells for pollen.
D. It “toughens” his immune system, adapting it to anaphylaxis.
E. It causes him to make more anti-pollen IgG, rather than IgE.

Answer 172

It causes him to make more anti-pollen IgG, rather than IgE.

Question 173

In the disease lupus, your B cells recognize your own DNA, causing a type III hypersensitivity.
How does this cause damage to your body?
A. Your antibodies bind DNA on the surface of mast cells, which release histamine.
B. The B cells then activate T cells, which mediate a cytotoxic response.
C. The B cells produce antibodies that bind to DNA and inhibit DNA replication.
D. DNA-Antibody complexes form and get stuck between cells, causing inflammation.
E. DNA acts like a hapten to allow IgG to bind your cells and recruit NK cells.

Answer 173

DNA-Antibody complexes form and get stuck between cells, causing inflammation.

Question 174

Which of the following is a similarity between Type I and Type IV hypersensitivity reactions?
A. the time it takes for the reactions to develop
B. the immune system cells that mediate the reaction
C. the need for prior exposure to the antigen that causes the reaction
D. the preferred treatment for the symptoms of the reaction
E. the type of antibodies involved in the reaction

Answer 174

the need for prior exposure to the antigen that causes the reaction

Question 175

Systemic Lupus Erythematosus . . .
A. is a serious bacterial infection of the whole body
B. is an autoimmune disease in which your T cells recognize your own proteins
C. involves production of antibodies that activate thyroid-stimulating hormone receptors
D. is an inherited immunodeficiency disease
E. involves formation of immune complexes containing your own DNA

Answer 175

involves formation of immune complexes containing your own DNA

Question 176

The measles virus is considered to cause an immunodeficiency disease because . . .
A. it causes you to produce antibodies against your own cells
B. it infects T cells and damages your cellular immune system
C. it can be transmitted vertically from mother to child
D. it occurs mainly in immunocompromised people
E. you can develop a Type I hypersensitivity response to it if you are infected more than once

Answer 176

it infects T cells and damages your cellular immune system

Question 177

A person with rheumatoid arthritis makes antibodies against the protein collagen, which is found in
cartilage. These antibodies can cause a Type III hypersensitivity reaction. Which of the following best
describes this reaction?
A. NK cells attack cartilage that has antibodies bound to it.
B. Mast cells bind the anti-collagen antibodies and release Type III mediators.
C. Neutrophils recruited by complement peptides release inflammatory cytokines.
D. IgE and IgG compete to form a complex that recruits TC cells and causes ADCC.
E. The excess presence of collagen causes a strong T cell response.

Answer 177

Neutrophils recruited by complement peptides release inflammatory cytokines.

Question 178

Interestingly, though food proteins are foreign, we usually do not have hypersensitivity reactions
against them. What do we think is the reason for this?
A. Oral presentation of antigens somehow stimulates regulatory T cells.
B. Most food proteins are denatured, and thus don’t elicit an immune response.
C. We produce enough IgG against them to out-compete the IgE.
D. Food proteins only encounter IgA, which produces a very weak immune response.
E. There are special cells in the gut that recognize “anti-PAMPs” in food.

Answer 178

Oral presentation of antigens somehow stimulates regulatory T cells.

Question 179

Type I (juvenile-onset) diabetes is caused by which of the following?
A. a congenital viral infection
B. a Type II hypersensitivity reaction involving maternal antibodies
C. self-recognizing TC cells that have not been deleted
D. a Type III autoimmune sequela to a bacterial infection
E. antibodies that recognize a person’s own DNA

Answer 179

self-recognizing TC cells that have not been deleted

Question 180

Which of the following is the best statement of the “hygiene hypothesis”?
A. Effective handwashing could reduce infectious disease transmission by up to 50%.
B. Oral vaccination creates a stronger immune response than injected vaccination.
C. Lack of personal hygiene leads to many fecal-oral bacterial infections.
D. The sicker someone is as a child, the more healthy they will be as an adult.
E. Lack of oral exposure to normal flora fails to induce the development of Treg cells.

Answer 180

Lack of oral exposure to normal flora fails to induce the development of Treg cells.

Question 181

People born with SCID can’t perform somatic recombination. Which of the following best
characterizes this condition?
A. lack of both cellular and humoral immunity, but normal innate immunity
B. lack of antibodies, but normal cellular immune responses
C. inability to delete self-recognizing B-cells or T-cells from the body
D. failure to produce memory cells that respond more quickly to a second infection
E. lack of cellular, humoral and innate immunity

Answer 181

lack of both cellular and humoral immunity, but normal innate immunity

Question 182

What is the purpose of a RhoGAM shot, as given to a pregnant Rh(-) woman?
A. To compete with her B cells for binding to fetal red blood cells
B. To direct NK cells to kill the mom’s B cells
C. To out-compete IgE so that the mom doesn’t get sensitized to Rh(+) red blood cells
D. To prevent the fetal red blood cells from crossing the placenta
E. To bind to the mom’s B cells and block the binding of Rh antigen

Answer 182

To compete with her B cells for binding to fetal red blood cells

Question 183

How does a Type III hypersensitivity reaction damage your tissues?
A. Misdirected TC and NK cells kill your own cells.
B. Macrophages recruited to the site of an infection start to digest your own cells.
C. Complement activation in capillaries recruits PMNs, which secrete perforins.
D. Infectious organisms survive within your macrophages, causing inflammation.
E. TH cells direct the release of mediators that cause fluid leakage from capillaries.

Answer 183

Complement activation in capillaries recruits PMNs, which secrete perforins.

Question 184

A TB test involves a Type IV hypersensitivity reaction. If you have been sensitized to TB before
you take such a test . . .
A. anti-TB antibodies circulating in your body will cause the test to be positive
B. Mast cells in your body will be coated with antibodies against TB
C. your macrophages will have TB living inside them, and this will cause a positive test
D. Tmemory cells in your body that recognize TB will cause the test to be positive
E. it won’t matter, since sensitization is not required for Type IV hypersensitivity

Answer 184

Tmemory cells in your body that recognize TB will cause the test to be positive

Question 185

Which of the following is an example of an acquired immunodeficiency disease?
A. Type I diabetes
B. Measles
C. Rheumatoid arthritis
D. SCID
E. Lupus

Answer 185

Measles

Question 186

How is IgA involved in the allergic response?
A. It is needed in order to produce IgE.
B. Its Fc part binds to Mast cells.
C. It is released from Mast cells once they have recognized an allergen twice.
D. It causes a greater inflammatory response than IgG does.
E. IgA is not involved in the allergic response.

Answer 186

IgA is not involved in the allergic response.

Question 187

If you are an Rh(-) woman and your husband is Rh(+), why do you need a RhoGAM shot, even for
your first pregnancy?
A. You could be allergic to your baby’s blood.
B. To avoid your B cells coming in contact with the Rh antigen.
C. So your antibodies don’t kill the baby’s blood cells.
D. To block the formation of immune complexes that may damage the baby’s capillaries.
E. You don’t. You need RhoGAM if you are Rh(+) and your husband is Rh(-).

Answer 187

To avoid your B cells coming in contact with the Rh antigen.

Question 188

Which of the following is most responsible for the symptoms associated with poison ivy?
A. Autoimmune antibodies
B. TC cells that recognize both poison ivy and your own antigens
C. An immunodeficiency disease you have before you contact the poison ivy
D. TH cells that activate macrophages in the skin
E. Bacteria that live on the poison ivy plants

Answer 188

TH cells that activate macrophages in the skin

Question 189

According to the “hygiene hypothesis” . . .
A. you need some good bacteria to fight off the bad ones
B. being “too clean” leads to death of your native flora
C. lack of exposure to gut flora leads to fewer Treg cells and more autoimmune diseases
D. childhood illness leads to a more robust immune response as an adult
E. washing hands appropriately is the single best way to reduce disease transmission

Answer 189

lack of exposure to gut flora leads to fewer Treg cells and more autoimmune diseases