Chapter 8: Adaptive Immunity
MULTIPLE CHOICE
1. Which primary characteristic is unique for the immune response?
a. The immune response is similar each time it is activated.
b. The immune response is specific to the antigen that initiates it.
c. The response to a specific pathogen is short term.
d. The response is innate, rather than acquired.
ANS: B
Unlike inflammation, which is nonspecifically activated by cellular damage and pathogenic
microorganisms, the immune response is primarily designed to afford long-term specific
protection (i.e., immunity) against particular invading microorganisms; that is, it has a
memory function. The other options are not unique characteristics of the immune response.
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2. In which structure does B lymphocytes mature and undergo changes that commit them to
becoming B cells?
a. Thymus gland
b. Regional lymph nodes
c. Bone marrow
d. Spleen
ANS: C
B lymphocytes mature and become B cells in specialized (primary) lymphoid organs—the
thymus gland for T cells and the bone marrow for B cells. Neither regional lymph nodes nor
the spleen are involved in changing B lymphocytes into B cells.
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3. What is the term for the process during which lymphoid stem cells migrate and change into
either immunocompetent T cells or immunocompetent B cells?
a. Clonal diversity
c. Clonal selection
b. Clonal differentiation
d. Clonal competence
ANS: A
The process is called the generation of clonal diversity and occurs in specialized (primary)
lymphoid organs—the thymus gland for T cells and the bone marrow for B cells. The other
options do not accurately identify the process described in the question.
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4. Which type of immunity is produced by an individual after either natural exposure to the
antigen or after immunization against the antigen?
a. Passive-acquired immunity
c. Passive-innate immunity
b. Active-acquired immunity
d. Active-innate immunity
ANS: B
An individual produces active-acquired immunity (active immunity) after natural exposure to
an antigen or after immunization, whereas passive-acquired immunity (passive immunity)
does not involve the host’s immune response at all. The innate immune system, also known as
nonspecific immune system and the first line of defense, is composed of the cells and
mechanisms that defend the host from infection by other organisms in a nonspecific manner,
which means that the cells of the innate system recognize and respond to pathogens in a
generic way.
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5. What type of immunity is produced when an immunoglobulin crosses the placenta?
a. Passive-acquired immunity
c. Passive-innate immunity
b. Active-acquired immunity
d. Active-innate immunity
ANS: A
Passive-acquired immunity (passive immunity) does not involve the host’s immune response
at all. Rather, passive immunity occurs when preformed antibodies or T lymphocytes are
transferred from a donor to the recipient. This transfer can occur naturally, as in the passage of
maternal antibodies across the placenta to the fetus, or artificially, as in a clinic using
immunotherapy for a specific disease. The remaining options do not produce immunity via
immunoglobulin transfer across the placenta.
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6. The portion of the antigen that is configured for recognition and binding is referred to as what
type of determinant?
a. Immunotope
b. Paratope
c. Epitope
d. Antigenitope
ANS: C
The precise portion of the antigen that is configured for recognition and binding is called its
antigenic determinant or epitope. The other options are not used to identify this portion of the
antigen.
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REF: Page 228
7. Which characteristic is the most important determinant of immunogenicity when considering
the antigen?
a. Size
b. Foreignness
c. Complexity
d. Quantity
ANS: B
Foremost among the criteria for immunogenicity is the antigen’s foreignness. A self-antigen
that fulfills all of these criteria except foreignness does not normally elicit an immune
response. Thus most individuals are tolerant of their own antigens. The immune system has an
exquisite ability to distinguish self (self-antigens) from nonself (foreign antigens). The other
options are considered when determining immunogenicity.
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8. When antigens are administered to produce immunity, why are different routes of
administration considered?
a. Different routes allow the speed of onset of the antigen to be varied, with the
intravenous route being the fastest.
b. Some individuals appear to be unable to respond to an antigen by a specific route,
thus requiring the availability of different routes for the same antigen.
c. Antigen-presenting cells are highly specialized and thus require stimulation by
different routes.
d. Each route stimulates a different lymphocyte-containing tissue, resulting in
different types of cellular and humoral immunity.
ANS: D
Each route preferentially stimulates a different set of lymphocyte-containing (lymphoid)
tissues and therefore results in the induction of different types of cell-mediated or humoral
immune responses. The other options do not accurately explain the use of different routes
when administering antigens to produce immunity.
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9. The functions of the major histocompatibility complex (MHC) and CD1 molecules are alike
because both:
a. Are antigen-presenting molecules.
b. Bind antigens to antibodies.
c. Secrete interleukins during the immune process.
d. Are capable of activating cytotoxic T lymphocytes.
ANS: A
MHC and CD1 molecules are both antigen presenting molecules (APCs). The other options
do not accurately describe the common function of these cells.
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10. Where are antibodies produced?
a. Helper T lymphocytes
b. Thymus gland
c. Plasma cells
d. Bone marrow
ANS: C
An antibody or immunoglobulin is a serum glycoprotein produced only by plasma cells in
response to a challenge by an immunogen.
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11. Which immunoglobulin is present in blood, saliva, breast milk, and respiratory secretions?
a. IgA
c. IgG
b. IgE
d. IgM
ANS: A
IgA can be divided into two subclasses, IgA1 and IgA2. IgA1 molecules are predominantly
found in the blood, whereas IgA2 is the predominant class of antibody found in normal body
secretions. The other options are not found in the substances identified in the question.
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12. Which antibody initially indicates a typical primary immune response?
a. IgG
b. IgM
c. IgA
d. IgE
ANS: B
Typically, IgM is produced first (primary immune response), followed by IgG against the
same antigen. The other options are not involved.
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13. An individual is more susceptible to infections of mucous membranes when he or she has a
seriously low level of which immunoglobulin antibody?
a. IgG
c. IgA
b. IgM
d. IgE
ANS: C
The IgA molecules found in bodily secretions are dimers anchored together through a J-chain
and secretory piece. This secretory piece is attached to the IgA antibodies inside the mucosal
epithelial cells and may function to protect these immunoglobulin antibodies against
degradation by enzymes also found in the secretions, thus decreasing the risk of infections in
the mucous membrane. The other options do not accurately identify the immunoglobulin
antibody involved in mucous membrane infections.
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14. The B-cell receptor (BCR) complex functions uniquely by:
a. Communicating information about the antigen to the helper T cell
b. Secreting chemical signals to communicate between cells
c. Recognizing the antigen on the surface of the B lymphocyte
d. Communicating information about the antigen to the cell nucleus
ANS: D
The role of the BCR is to recognize the antigen; however, unlike circulating antibodies, the
receptor must communicate that information to the cell’s nucleus. The other options are not
unique to the function of the BCR complex.
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15. The generation of clonal diversity occurs primarily during which phase of life?
a. Fetal
c. Infancy
b. Neonatal
d. Puberty
ANS: A
Generation of clonal diversity primarily occurs in the fetus and probably continues to a low
degree throughout most of adult life.
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REF: Pages 236-237
16. The generation of clonal diversity includes a process that:
a. Involves antigens that select those lymphocytes with compatible receptors.
b. Allows the differentiation of cells into antibody-secreting plasma cells or mature T
cells.
c. Takes place in the primary (central) lymphoid organs.
d. Causes antigens to expand and diversify their populations.
ANS: C
This process occurs in central lymphoid organs—the thymus gland for T cells and bone
marrow for B cells. The other options do not accurately describe the processes included in
clonal diversity.
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REF: Pages 236-237
17. Which statement is true concerning clonal selection?
a. Clonal selection is driven by hormones and does not require foreign antigens.
b. This theory involves antigens that select those lymphocytes with compatible
receptors.
c. Clonal selection takes place in the primary (central) lymphoid organs.
d. This process generates immature but immunocompetent T and B cells with
receptors.
ANS: B
Clonal selection, a process during which antigens select those lymphocytes with compatible
receptors, expands their population and causes differentiation into antibody-secreting plasma
cells or mature T cells (see Table 8-6). The other statements are not true regarding clonal
selection.
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18. Which is an example of an endogenous antigen?
a. Yeast
c. Bacteria
b. Cancer cells
d. Fungus
ANS: B
Of the options provided, endogenous antigens include only those uniquely produced by
cancerous cells.
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19. Which cytokine is needed for the maturation of a functional helper T cell?
a. IL-1
c. IL-4
b. IL-2
d. IL-12
ANS: B
Of the options provided, IL-2 production is critical for the Th cell to mature efficiently into a
functional helper cell.
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20. Th2 cells produce IL-4 and suppress which cells?
a. B lymphocytes
c. Th1 cells
b. Cytotoxic T lymphocytes
d. Memory T lymphocytes
ANS: C
Th2 cells produce IL-4, which suppresses only Th1 and Th17 cells through their IL-4
receptors.
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21. Which statement is believed to be true concerning Th1 cells?
a. Th1 cells are induced by antigens derived from allergens.
b. They are induced by antigens derived from cancer cells.
c. Th1 cells produce IL-4, IL-5, IL-6, and IL-13.
d. They assist in the development of humoral immunity.
ANS: B
Antigens derived from viral or bacterial pathogens and those derived from cancer cells are
hypothesized to induce a greater number of Th1 cells relative to Th2 cells. The other
statements are not true regarding Th1 cells.
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REF: Pages 246-247
22. Which statement is believed to be true concerning Th2 cells?
a. Th2 cells are induced by antigens derived from allergens.
b. They are induced by antigens derived from cancer cells.
c. Th2 cells produce IL-2, TNF-ß, and IFN- .
d. They assist in the development of cell-mediated immunity.
ANS: A
Antigens derived from multicellular parasites and allergens are hypothesized to be involved in
the production of more Th2 cells. The other statements are not true regarding Th2 cells.
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23. When a person is exposed to most antigens, antibodies can be usually detected in his or her
circulation within:
a. 12 hours
b. 24 hours
c. 3 days
d. 6 days
ANS: D
After only approximately 5 to 7 days is an IgM antibody specific for that antigen detected in
the circulation.
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24. Vaccinations are able to provide protection against certain microorganisms because of the:
a. Strong response from IgM
c. Memory cells for IgE
b. Level of protection provided by IgG
d. Rapid response from IgA
ANS: B
IgG production is considerably increased, making it the predominant antibody class of the
secondary response. IgG is often present in concentrations several times larger than those of
IgM, and levels of circulating IgG specific for that antigen may remain elevated for an
extended period. The other options are not relevant to how vaccinations protect against certain
microorganisms.
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25. Why is the herpes virus inaccessible to antibodies after the initial infection?
a.
b.
c.
d.
The virus does not circulate in the blood.
It does not have antibody receptors.
It resists agglutination.
The virus is a soluble antigen.
ANS: A
Many viruses (e.g., measles, herpes) are inaccessible to antibodies after the initial infection
only because these viruses do not circulate in the bloodstream; rather, they remain inside
infected cells, spreading by direct cell-to-cell contact.
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26. Increased age may cause which change in lymphocyte function?
a. Increased production of antibodies against self-antigens
b. Decreased number of circulating T cells
c. Decreased production of autoantibodies
d. Increased production of helper T cells
ANS: A
B-cell function is altered with age as shown by decreases in specific antibody production in
response to antigenic challenge, with concomitant increases in circulating immune complexes
and in circulating autoantibodies (antibodies against self-antigens). Aging does not play a role
in either decreasing T cells circulation or increasing helper T cells production.
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27. How do antibodies protect the host from bacterial toxins?
a. Lysing the cell membrane of the toxins
b. Binding to the toxins to neutralize their biologic effects
c. Inhibiting the synthesis of DNA proteins needed for growth
d. Interfering with the DNA enzyme needed for replication
ANS: B
To cause disease, most toxins must bind to surface molecules on the individual’s cells.
Protective antibodies can bind to the toxins, prevent their interaction with cells, and neutralize
their biologic effects. The other options fail to explain how antibodies protect the host from
bacterial toxins.
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28. Which T cell controls or limits the immune response to protect the host’s own tissues against
an autoimmune response?
a. Cytotoxic T cells
b. Th1 cells
c. Th2 cells
d. Regulatory T (Treg) cells
ANS: D
The regulatory T (Treg) cell is the only option whose role is to control or limit the immune
response to protect the host’s own tissues against autoimmune reactions.
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29. Evaluation of umbilical cord blood can confirm that which immunoglobulin level is near adult
levels?
a. IgA
b. IgG
c. IgM
d. IgE
ANS: B
At birth, the total IgG level in the umbilical cord is the only immunoglobulin that is near adult
levels (see Figure 8-30).
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30. Which statement is true concerning the IgM?
a. IgM is the first antibody produced during the initial response to an antigen.
b. IgM mediates many common allergic responses.
c. IgM is the most abundant class of immunoglobulins.
d. IgM is capable of crossing the human placenta.
ANS: A
Typically, IgM is produced first (primary immune response), followed by IgG against the
same antigen. The other options are not true statements regarding IgM.
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31. Which cell has the ability to recognize antigens presented by the MHC class I molecules?
a. T cytotoxic
c. CD 8
b. CD 4
d. T helper
ANS: C
CD8 cells recognize antigens presented by the major histocompatibility complex (MHC) class
I molecules and become mediators of cell-mediated immunity and directly kill other cells (Tcytotoxic cells). CD4 cells tend to recognize antigen presented by MHC class II molecules
and develop into helpers in the later clonal selection process (T-helper cells)
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32. Which cell has a role in developing cell-mediated immunity?
a. Th1
c. CD8
b. CD4
d. Th2
ANS: A
Only Th1 cells help develop cellular immunity.
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REF: Pages 245-246
33. How does the aging process of the T-cell activity affect older adults?
a. Poor heat regulation abilities
b. Increased risk for bone fractures
c. Tendency to develop various infections
d. Likelihood of experiencing benign skin lesions
ANS: C
T-cell activity is deficient in older adults, and a shift in the balance of T-cell subsets is
observed. These changes may result in increased susceptibility to infection. The other issues
are not related to T-cell activity.
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REF: Pages 257-258
34. Which statement is true regarding maternal antibodies provided to the neonate?
a. The antibodies enter into the fetal circulation by means of active transport.
b. The antibodies are transferred to the fetus via the lymphatic system.
c. The antibodies are directly related to the mother’s nutritional intake.
d. The antibodies reach protective levels after approximately 6 months of age.
ANS: A
To protect the child against infectious agents both in utero and during the first few postnatal
months, a system of active transport facilitates the passage of maternal antibodies into the
fetal circulation. The antibodies are transmitted via the placenta and are related to the
mother’s immune system. The infant’s own IgG-related antibodies reach protective levels by
6 months of age.
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35. Antibodies that are associated with mucosal immune system, such as immunoglobulins,
function to prevent which type of infections?
a. Infections that attack the respiratory system
b. Infections that tend to be chronic in nature
c. Infections likely to be resistant to antibiotics
d. Infections that focus on epithelial surfaces of the body
ANS: D
Antibodies of the systemic immune system function throughout the body, whereas antibodies
of the secretory (mucosal) immune system—primarily immunoglobulins of the IgA class—are
associated with bodily secretions and function to prevent pathogenic infection on epithelial
surfaces. The other options are not necessarily true when considering the immunoglobulins.
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REF: Pages 252-253
36. Cytokines are vital to a cell’s ability to do which function?
a. Excrete
c. Metabolize
b. Reproduce
d. Communicate
ANS: D
During their interactions, cells must communicate with each other through soluble cytokines.
The other options are not so rigidly related to cytokines.
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REF: Pages 235-236
MULTIPLE RESPONSE
37. Which is an example of a bacterial toxin that has been inactivated but still retains its
immunogenicity to protect the person? (Select all that apply.)
a. Poliomyelitis
b.
c.
d.
e.
Measles
Tetanus
Gonorrhea
Diphtheria
ANS: C, E
The symptoms of tetanus or diphtheria are mediated by specific toxins. To prevent harming
the recipient of the immunization, bacterial toxins are chemically inactivated so that they have
lost most of their harmful properties but still retain their immunogenicity. These agents are
referred to as toxoids. Tetanus or diphtheria are the only examples of such inactivated toxins.
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38. Which statements are true concerning the humoral immune response? (Select all that apply.)
a. The humoral immune response is divided into major and minor phases.
b. The response has IgG and IgM produced during each of its phrases.
c. It has a greater presence of IgG than IgM in one of its phases.
d. The humoral immune response is produced in reaction to the presence of an
antigen.
e. Phases differ in their response time as a result of the effect of memory cells.
ANS: B, C, D, E
The humoral immune response is divided into two phases, primary and secondary. These
phases differ in the relative amounts of IgG produced—the secondary response having a
significantly higher proportion of IgG relative to IgM. The two phases also differ in the speed
with which each occurs after the antigen challenge—the secondary phases is significantly
more rapid than the primary phase because of the presence of memory cells in the secondary
phase.
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REF: Page 247
39. CD4 is a characteristic surface marker and a result of which of the following? (Select all that
apply.)
a. Activity in the primary lymphoid organs
b. Process of cellular differentiation
c. Alterations to T cells
d. Changes to B cells
e. Clonal selection
ANS: A, B, C, D
Differentiation of B cells and T cells in the primary lymphoid organs results in the expression
of several characteristic surface markers, such as CD4 on helper T cells, CD8 on cytotoxic T
cells, and CD21 and CD40 on B cells. Clonal selection is the process during which antigens
select those lymphocytes with complementary T-cell receptors (TCRs) or BCRs.
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REF: Pages 236-241 | Page 258
40. What are the necessary components of an adaptive immune response? (Select all that apply.)
a. Antigen
b. Gamma IgG
c. Lymphocyte surface receptors
d. Crystalline fragment
e. Antibody
ANS: A, C, E
Antigens are the molecules that can react with components of the adaptive immune system,
including antibodies and lymphocyte surface receptors.
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MATCHING
Match each immunoglobulin with its characteristic or function. Each immunoglobulin can be
used only once.
______ A. IgA
______ B. IgE
______ C. IgG
41. Crosses the placenta.
42. Is predominantly found in the blood and body secretions.
43. Mediates many common allergic responses
41. ANS: C
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MSC: As a result of selective transport across the placenta, maternal IgG is the major class of
antibody found in the blood of the fetus and newborn.
42. ANS: A
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MSC: IgA can be divided into two subclasses, IgA1 and IgA2. IgA1 molecules are found
predominantly in the blood, whereas IgA2 is the predominant class of antibody found in normal body
secretions.
43. ANS: B
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MSC: IgE is the least concentrated of any of the immunoglobulin classes in the circulation. It appears
to have very specialized functions as a mediator of many common allergic responses and in the
defense against parasitic infections.