Chapter 21
The Immune System: Innate and Adaptive Body Defenses
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21
22.
What is the role of the variable regions of an antibody? Of the
constant regions?
23.
Name the five antibody classes and describe where each is most
likely to be found in the body.
24.
How do antibodies help defend the body?
25.
Do vaccines produce active or passive humoral immunity?
Explain your answer. Why is passive immunity less satisfactory?
26.
Describe the process of activation of a CD4 T cell.
27.
Describe the specific roles of helper, regulatory, and cytotoxic T
cells in normal cellular immunity.
28.
Name several cytokines and describe their role in the immune
response.
29.
Define hypersensitivity. List three types of hypersensitivity
reactions. For each, note whether antibodies or T cells are
involved and provide two examples.
30.
What events can result in autoimmune disease?
31.
What accounts for the declining efficiency of the immune system
with age?
Critical Thinking
and Clinical Application
Questions
1.
Jenny, a 6-year-old child who has been raised in a germ-free
environment from birth, is a victim of one of the most severe
examples of an abnormal immune system. Jenny also suffers from
cancer caused by the Epstein-Barr virus. Relative to this case:
(a)
What is the usual fate of children with Jenny’s condition and
similar circumstances if no treatment is attempted?
(b)
Why is
Jenny’s brother chosen as the hematopoietic stem cell donor?
(c)
Why is her physician planning to use umbilical cord blood as
a source of stem cells for transplant if her brother’s stem cells fail
(what are the hoped-for results)?
(d)
Attempt to explain Jenny’s
cancer.
(e)
What similarities and dissimilarities exist between
Jenny’s illness and AIDS?
2.
Some people with a deficit of IgA exhibit recurrent respiratory
tract infections. Explain this observation.
3.
Capillary permeability increases and plasma proteins leak into
the interstitial fluid as part of the inflammatory process. Why is
this desirable?
4.
Costanza was picking grapes in her father’s arbor when she felt
a short prickling pain in her finger. She ran crying to her father,
who removed an insect stinger and calmed her with a glass
of lemonade. Twenty minutes later Costanza’s finger was red,
swollen, and throbbing where she had been stung. What type of
immune response was she exhibiting? What treatment would
relieve her discomfort?
5.
Caroline, a pregnant 29-year-old, has been HIV-positive for
at least 10 years, dating back to when she was homeless and
injecting heroin on a regular basis. While she currently has no
symptoms of AIDS, she is taking several medications and is
worried about the possibility that her baby might be infected.
How do you think the HIV virus might be transferred from a
mother to her offspring? Which of Caroline’s cells are infected by
the virus and why is the viral attack on these cells so devastating?
Why is Caroline taking medication even though she has no
symptoms? What types of medications might she be taking and
how do they affect the virus and its replication?
4.
Which of the following antibodies can fix complement?
(a)
IgA,
(b)
IgD,
(c)
IgE,
(d)
IgG,
(e)
IgM.
5.
Which antibody class is abundant in body secretions?
(a)
IgA,
(b)
IgD,
(c)
IgE,
(d)
IgG,
(e)
IgM.
6.
Small molecules that must combine with large proteins to become
immunogenic are called
(a)
complete antigens,
(b)
kinins,
(c)
antigenic determinants,
(d)
haptens.
7.
Lymphocytes that develop immunocompetence in the bone
marrow are
(a)
T lymphocytes,
(b)
B lymphocytes,
(c)
NK cells,
(d)
B and T lymphocytes.
8.
Cells that can directly attack target cells include all of the
following
except
(a)
macrophages,
(b)
cytotoxic T cells,
(c)
helper
T cells,
(d)
natural killer cells.
9.
Which of the following is not involved in the activation of a
B cell?
(a)
antigen,
(b)
helper T cell,
(c)
cytokine,
(d)
cytotoxic
T cell.
10.
±e cell type most o²en invaded by HIV is a(n)
(a)
eosinophil,
(b)
cytotoxic T cell,
(c)
natural killer cell,
(d)
helper T cell,
(e)
B cell.
11.
Complement fixation promotes all of the following except
(a)
cell
lysis,
(b)
inflammation,
(c)
opsonization,
(d)
interferon release,
(e)
chemotaxis of neutrophils and other cells.
12.
Using the letters from column B, match the cell description in
column A. (Note that all require more than a single choice.)
Column A
____ (1)
phagocyte
____ (2)
releases histamine
____ (3)
releases perforins
____ (4)
lymphocyte
____ (5)
effector cells of
adaptive immunity
____ (6)
antigen-presenting cell
Column B
(a)
natural killer cell
(b)
neutrophil
(c)
dendritic cell
(d)
mast cell
(e)
cytotoxic T cell
(f)
B cell
(g)
macrophage
(h)
helper T cell
(i)
basophil
Short Answer Essay Questions
13.
Besides acting as mechanical barriers, the skin epidermis and
mucosae of the body have other attributes that contribute to
their protective roles. Cite the common body locations and the
importance of mucus, lysozyme, keratin, acid pH, and cilia.
14.
Explain why attempts at phagocytosis are not always successful;
cite factors that increase the likelihood of success.
15.
What is complement? How does it cause bacterial lysis? What are
some of the other roles of complement?
16.
Interferons are referred to as antiviral proteins. What stimulates
their production, and how do they protect uninfected cells?
Which cells of the body secrete interferons?
17.
Differentiate between humoral and cellular adaptive immunity.
18.
Although the adaptive immune system has two arms, it has been
said, “no T cells, no immunity.” Explain.
19.
Define immunocompetence and self-tolerance. How is self-
tolerance achieved?
20.
Differentiate between a primary and a secondary immune
response. Which is more rapid and why?
21.
Define antibody. Using an appropriately labeled diagram,
describe the structure of an antibody monomer. Indicate and
label variable and constant regions, heavy and light chains.
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