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1
The process of phagocytosis is an integral part of both specific and nonspecific immune defense activities.
A)True
B)False
2
There are three major groups of phagocytic cells: (1) neutrophils; (2) mononuclear phagocyte system (monocytes and macrophages); and (3) organ-specific phagocytes in the liver, spleen, lymph nodes, lungs, and brain.
A)True
B)False
3
Blood flowing through capillaries of the liver and spleen encounter "fixed" phagocytic cells that do not travel from organ to organ yet remove locally invading pathogens, rendering the blood sterile after a few passes.
A)True
B)False
4
Chemotaxis refers to the movement of phagocytes to the site of an infection, lured by chemical attractants.
A)True
B)False
5
Macrophages are monocytes that have transformed and become phagocytic after exposure to some foreign substance at the site of an infection.
A)True
B)False
6
Diapedesis refers to the movement of large phagocytic cells from the capillary blood as they squeeze between adjacent endothelial cells and into the tissue spaces.
A)True
B)False
7
Many fevers result from exposure to certain bacteria that release endogenous pyrogens that stimulate leukocytes to release chemicals known as endotoxins.
A)True
B)False
8
Interferons are polypeptides produced in small amounts by host cells infected with one virus, which can then interfere with the ability of a second, unrelated strain of virus to infect other cells in the same host.
A)True
B)False
9
There are three major categories of interferons: alpha, beta, and gamma interferons that have been approved by the Food and Drug Administration (FDA) for treatment of a number of diseases.
A)True
B)False
10
Most antigens are proteins because of their large size and their complexity of shape.
A)True
B)False
11
About 65% to 85% of circulating lymphocytes in blood and most of the lymphocytes in the germinal centers of lymph nodes and spleen are B lymphocytes.
A)True
B)False
12
B lymphocytes exposed to antigens can transform into plasma cells and produce large quantities of antibodies.
A)True
B)False
13
Most of the immunoglobulins in external secretions are in the IgA subclass, whereas most of the antibodies in serum, are in the IgG subclass.
A)True
B)False
14
All antibodies have a "Y" shape composed of four interconnected protein chains, with the "fork" region serving as the antigen-binding fragment and the "stalk'' region serving as the crystallizable fragment.
A)True
B)False
15
The B lymphocytes have antibodies on their cell membrane that serve as receptors for appropriate antigens, such that when stimulated by these antigens, the B cells divide and produce and release more of the specific antibodies like those on the membrane.
A)True
B)False
16
As part of the attack phase, complement proteins C5 through C9 open large pores in membranes of the victim cells allowing water to enter; and thus causing these cells to swell and burst.
A)True
B)False
17
Histamine causes vasodilation and increased capillary permeability, thereby allowing plasma proteins to leak out and into the tissue fluid resulting in localized swelling or edema.
A)True
B)False
18
Untreated local infections may result in a fever when endogenous pyrogen molecules are released from leukocytes and macrophages, altering the "thermostat" in the hypothalamus.
A)True
B)False
19
Edward Jenner is the English physician who inoculated a healthy boy with cowpox, and later, with smallpox to demonstrate the boy's immunity.
A)True
B)False
20
The term attenuation refers to a laboratory process in which the antigens present on a pathogen are altered slightly to decrease the virulence but retain the antigenicity.
A)True
B)False
21
Louis Pasteur isolated the bacteria that caused the disease called anthrax, and using attenuated bacteria, successfully immunized cows against anthrax, demonstrating the first vaccine.
A)True
B)False
22
The primary response results in the greater secretion of antibodies--sooner, faster, and with longer maintained protection.
A)True
B)False
23
A single B lymphocyte can produce only one type of antibody, with specificity for only one specific type of antigen molecule.
A)True
B)False
24
According to the clonal selection theory, foreign antigens select and interact with surface receptors only on the membranes of those specific lymphocytes that are genetically capable of making antibody molecules against those antigens.
A)True
B)False
25
A vaccine is usually a pathogen that has been treated to reduce or destroy its antigenicity but retains its virulence.
A)True
B)False
26
The term passive immunity refers to the immune protection that can be produced by the transfer of antibodies to a recipient from another person or from an animal.
A)True
B)False
27
The immunity acquired from an immunization is an example of passive immunity.
A)True
B)False
28
Identical monoclonal antibodies are produced by specific B lymphocyte-cancer cell hybridoma clones against one specific antigenic determinant molecule.
A)True
B)False
29
The virus that causes acquired immune deficiency syndrome specifically attacks cytotoxic T cells.
A)True
B)False
30
Unlike the short five- to seven-day life span of the B lymphocyte, the small T lymphocyte have a long life that spans months or perhaps years, especially those that have not yet been stimulated by antigens.
A)True
B)False
31
Most bacterial infections are fought by antibodies from B cells (humoral) rather than by direct cell-mediated contact from T lymphocytes; with one exception being the T lymphocyte attack on the tubercle bacillus bacteria that cause tuberculosis.
A)True
B)False
32
The immune response of B cells and killer (cytotoxic) T cells is decreased by helper T lymphocytes and increased by suppressor T lymphocytes.
A)True
B)False
33
Acquired immune deficiency syndrome is currently treated using a variety of drugs, one of which is a reverse transciptase inhibitor that inhibits the replication of the virus.
A)True
B)False
34
The lymphokines can be considered cytokines secreted by lymphocytes, whereas the term interleukin refers to a cytokine whose amino acid sequence has been identified.
A)True
B)False
35
There appears to be two subtypes of helper T lymphocytes--the TH1 subtypes that secrete interleukin-4 and other lymphokines to stimulate T lymphocyte humoral immunity and the TH2 subtypes that secrete lymphokines that promote B lymphocyte cell-mediated immunity.
A)True
B)False
36
Tumor infiltrating lymphocytes invade and destroy solid tumors.
A)True
B)False
37
In order for a T lymphocyte to respond to a foreign antigen, that antigen must be attached to the membrane of another cell, such as a macrophage for example, that will then "present" the foreign antigen to the T lymphocyte.
A)True
B)False
38
Synthesis of the histocompatibility antigens is directed by a group of four genes labeled A, B, C, and D that are located on chromosome number 6; and together, are known as the major histocompatibility complex (MHC).
A)True
B)False
39
Histocompatibility genes A, B, C, and D produce class-2 protein molecules that are ultimately placed on the plasma membrane of all cells in the body except mature red blood cells.
A)True
B)False
40
The coreceptor protein known as CD8 is associated with the killer T lymphocyte membrane receptor and the coreceptor protein known as CD4 is associated with the helper T lymphocyte membrane receptor.
A)True
B)False
41
Interleukin-2 stimulates the proliferation of activated B cells.
A)True
B)False
42
After an infection has been successfully cleared from the body, the activated T lymphocytes must be destroyed. These T lymphocytes undergo apoptosis by producing a membrane surface receptor protein called FAS ligand that signals self-destruction.
A)True
B)False
43
Immune tolerance is more complete and longer lasting when antigens are exposed to the weak immune system of an adult than when exposed to that of a fetus or newborn.
A)True
B)False
44
Two general proposals to help explain the mechanisms of immune tolerance are the clonal deletion theory in which lymphocytes recognizing self-antigens are destroyed, and the clonal anergy ("without working") theory in which these lymphocytes are always present but are permanently inactivated.
A)True
B)False
45
Most tumors appear to be specific cell clones that escape the normal inhibitory controls and behave in a relatively more unspecialized way.
A)True
B)False
46
Tumors are usually described as either benign or metastatic.
A)True
B)False
47
Carcinoembryonic antigen tests help in the diagnosis of liver cancer whereas the tests for alpha-fetoprotein aids in the diagnosis of colon cancer.
A)True
B)False
48
The risk of developing cancer decreases with age partly because aging lymphocytes appear to become more resistant to carcinogens over time.
A)True
B)False
49
Autoimmune diseases result in the production of autoantibodies by T cells to self-antigens, which may result in inflammation and organ damage or even organ death.
A)True
B)False
50
Rheumatoid arthritis and rheumatic fever are examples of two autoimmune diseases that are caused by very similar defects in the immune system.
A)True
B)False
51
Delayed hypersensitivity is caused by an abnormal T lymphocyte response to an allergen, whereas immediate hypersensitivity is due to an abnormal B lymphocyte response.
A)True
B)False
52
Allergy and immediate hypersensitivity refer to the same antibody response by the immune system to the presence of antigens, known as allergens.
A)True
B)False
53
In the typical flare-and-wheal reaction that occurs following a skin test for allergies, the flare is due to local edema, and the wheal results from the vasodilation of blood vessels.
A)True
B)False
54
One of the best-known examples of delayed hypersensitivity is contact dermatitis, caused by poison ivy, poison oak, and poison sumac.
A)True
B)False





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