Ch. 43
A
71) Some pathogens can undergo rapid changes resulting in antigenic variation. Which of the following is such a pathogen? A) the influenza virus, which expresses alternative envelope proteins B) the strep bacteria, which can be communicated from patient to patient with high efficiency C) human papilloma virus, that can remain latent for several years D) the causative agent of an autoimmune disease such as rheumatoid arthritis E) multiple sclerosis, that attacks the myelinated cells of the nervous system
A
9) In some insects, such as Drosophila, fungal cell wall elements can activate the protein Toll. What is Tollȇs function? A) acts as a receptor that, when activated, signals synthesis of antimicrobial peptides B) functions directly to attack the fungi presented to it C) produces antimicrobial peptides by interaction with chitin D) secretes special recognition signal molecules that identifies specific pathogens E) causes some hemocytes to phagocytize the pathogens
E
A bacterium entering the body through a small cut in the skin will do which of the following? A) inactivate the erythrocytes B) stimulate apoptosis of nearby body cells C) stimulate release of interferons D) stimulate natural killer cell activity E) activate a group of proteins called complement
A
A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Janeʹs cousin Bob), even though Jane has previously given blood for one of Bobʹs needed transfusions. Which of the following might account for this? A) Janeʹs blood type is a match to Bobʹs but her MHC proteins are not. B) A blood type match is less stringent than a match required for transplant because blood is more tolerant of change. C) For each gene, there is only one blood allele but many tissue alleles. D) Janeʹs class II genes are not expressed in bone marrow. E) Bobʹs immune response has been made inadequate before he receives the transplant.
E
A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to A) respond to T-independent antigens. B) lyse tumor cells. C) stimulate a cytotoxic T cell. D) interact with a class I MHC-antigen complex. E) interact with a class II MHC-antigen complex.
D
A patient can produce antibodies against some bacterial pathogens, but he does not produce antibodies against viral infections. This is probably due to a disorder in which cells of the immune system? A) B cells B) plasma cells C) natural killer cells D) T cells E) macrophages
D
A patient reports severe symptoms of watery, itchy eyes and sneezing after being given a flower bouquet as a birthday gift. A reasonable initial treatment would involve the use of A) a vaccine. B) complement. C) sterile pollen. D) antihistamines. E) monoclonal antibodies.
E
A patient undergoes a high level of mast cell degranulation, dilation of blood vessels, and acute drop in blood pressure. These symptoms could be caused by which of the following? A) an autoimmune disease B) a typical allergy that can be treated by antihistamines C) an organ transplant, such as a skin graft D) the effect of exhaustion on the immune system E) anaphylactic shock immediately following exposure to an allergen
C
A person exposed to a new cold virus would not feel better for one to two weeks because A) specific B cells and T cells must be selected prior to a protective response. B) it takes up to two weeks to stimulate immunologic memory cells. C) no memory cells can be called upon, so adequate response is slow. D) antigen receptors are not the same as for a flu virus to which she has previously been exposed. E) V-J gene rearrangement must occur prior to a response.
D
A researcher is analyzing the immune response of a patient following the patientʹs exposure to an unknown agent while out of the country. The patientʹs blood is found to have a high proportion of lymphocytes with CD8 surface proteins. What is the likely cause? A) The patient encountered a bacterial infection which elicited CD8 marked T cells. B) The disease must have been caused by a multicellular parasite, such as can be encountered in polluted water sources. C) The CD8 proteins would be discharged from these lymphocytes to lyse the infected cells. D) The CD8 proteins marked the surfaces of cytotoxic T cells to attack virus-infected host cells. E) CD8 marks the surface of cells that accumulate after the infection is over and signal patient recovery.
B
A transfusion of type A blood given to a person who has type O blood would result in which of the following? A) the recipientʹs B antigens reacting with the donated anti-B antibodies B) the recipientʹs anti-A antibodies clumping the donated red blood cells C) the recipientʹs anti-A and anti-O antibodies reacting with the donated red blood cells if the donor was a heterozygote (Ai) for blood type D) no reaction because type O is a universal donor E) no reaction because the O-type individual does not have antibodies
C
An epitope associates with which part of an antibody? A) the antibody-binding site B) the heavy-chain constant regions only C) variable regions of a heavy chain and light chain combined D) the light-chain constant regions only E) the antibody tail
A
An immune response to a tissue graft will differ from an immune response to a bacterium because A) MHC molecules of the donor may stimulate rejection of the graft tissue. B) the tissue graft, unlike the bacterium, is isolated from the circulation and will not enter into an immune response. C) a response to the graft will involve T cells and a response to the bacterium will not. D) a bacterium cannot escape the immune system by replicating inside normal body cells. E) the graft will stimulate an autoimmune response in the recipient.
A
An immunoglobulin (Ig) molecule, of whatever class, has regions symbolized as C or V, H or L. A light chain has which of these regions? A) one C and one V region B) three C and one V region C) one H and one L region D) three H and one L region E) two C and two V regions
B
An invertebrate, such as an insect, has innate immunity that can be nonspecific about which pathogens are prevented from harming its metabolism. Which of the following is most likely to function this way in the insectʹs intestine? A) complement B) lysozyme C) mucus D) neutrophils E) dendritic cells
E
B cells interacting with helper T cells are stimulated to differentiate when A) B cells produce IgE antibodies. B) B cells release cytokines. C) helper T cells present the class II MHC molecule-antigen complex on their surface. D) helper T cells differentiate into cytotoxic T cells. E) helper T cells release cytokines.
A
Both lysozyme and cytotoxic T cells A) kill cells through chemical interactions. B) kill cells by inducing apoptosis. C) kill cells by generating a membrane attack complex. D) are part of innate immunity. E) are involved in cell-mediated immune responses.
D
Both the eye and the respiratory tract are protected against infections by which of the following? A) the mucous membranes that cover their surface B) the secretion of complement proteins C) the release of slightly acidic secretions D) the secretion of lysozyme onto their surface E) interferons produced by immune cells
B
Clonal selection implies that A) brothers and sisters have similar immune responses. B) antigens increase mitosis in specific lymphocytes. C) only certain cells can produce interferon. D) a B cell has multiple types of antigen receptors. E) the body selects which antigens it will respond to.
C
Clonal selection is an explanation for how A) a single type of stem cell can produce both red blood cells and white blood cells. B) V, J, and C gene segments are rearranged. C) an antigen can provoke production of high levels of specific antibodies. D) HIV can disrupt the immune system. E) macrophages can recognize specific T cells and B cells.
C
For one person to produce over a million different antibody molecules could not possibly require over a million different genes. Instead, this variability is accounted for by which processes? A) alternative splicing of exons after transcription B) increased rate of mutation in the RNA molecules C) DNA rearrangements followed by alternative splicing of the transcripts D) DNA rearrangements in the thymus cells E) crossing-over between the light and heavy chains of each antibody molecule during meiosis I
B
HIV targets include all of the following except A) macrophages. B) cytotoxic T cells. C) helper T cells. D) cells bearing CD4. E) brain cells.
D
Histamines trigger dilation of nearby blood vessels, and increase in their permeability. Which of the signs of inflammation are therefore associated with histamine release? A) redness and heat only B) swelling only C) pain D) redness, heat, and swelling E) all of the signs of inflammation
B
How do antibodies of the different classes IgM, IgG, IgA, IgD, and IgE differ from each other ? A) in the way they are produced B) in their heavy chain structure C) in the type of cell that produces them D) by the antigenic determinants that they recognize E) by the number of carbohydrate subunits they have
A
How do people contract salmonella poisoning? A) The microbe can survive the acidic environment of the stomach and resist lysosomal degradation in macrophages. B) The chemotactic messengers released by the salmonella bacterium do not attract sufficient neutrophils to entirely destroy the infection. C) There is a delay in selection of the population of eosinophils that recognize and are responsible for fighting these bacterial infections. D) The bacterium releases chemical messengers that make it resistant to phagocytosis. E) The combination of foods eaten at the meal reduces the pH of the stomach sufficiently so that the bacterium was not destroyed.
D
If a newborn were accidentally given a drug that destroyed the thymus, what would most likely happen? A) His cells would lack class I MHC molecules on their surface. B) His humoral immunity would be missing. C) Genetic rearrangement of antigen receptors would not occur. D) His T cells would not mature and differentiate appropriately. E) His B cells would be reduced in number and antibodies would not form.
C
In the human disease known as lupus, there is an immune reaction against a patientʹs own DNA from broken or dying cells. This kind of response typifies which kind of irregularity? A) allergy B) immunodeficiency C) autoimmune disease D) antigenic variation E) cancer
A
In which of the following situations will helper T cells be activated? A) when an antigen is displayed by a dendritic cell B) when a cytotoxic T cell releases cytokines C) when natural killer (NK) cells come in contact with a tumor cell D) in the bone marrow during the self-tolerance test E) when B cells respond to T-independent antigens
B
Inflammatory responses may include which of the following? A) clotting proteins migrating away from the site of infection B) increased activity of phagocytes in an inflamed area C) reduced permeability of blood vessels to conserve plasma D) release of substances to decrease the blood supply to an inflamed area E) inhibiting the release of white blood cells from bone marrow
D
Jenner successfully used cowpox virus as a vaccine against the virus that causes smallpox. Why was he successful even though he used viruses of different kinds? A) The immune system responds nonspecifically to antigens. B) The cowpox virus made antibodies in response to the presence of smallpox. C) Cowpox and smallpox are antibodies with similar immunizing properties. D) There are some antigenic determinants common to both pox viruses.
C
Mammals have Toll-like receptors (TLRs) that act in a manner similar to those of insects. While not specific to a particular pathogen, a TLR can recognize a kind of macromolecule that is absent from vertebrates but present in/on certain groups of pathogens. Which of the following is most likely to be recognized by a particular TLR that defends against some viruses? A) lipopolysaccharides B) double-stranded DNA C) double-stranded RNA D) glycoproteins E) phospholipids
C
Most newly emerging diseases, no matter how severe their effects on a population, human or otherwise, have which of the following in common? A) greater severity as there are more and more occurrences of the infection B) major pandemics, spreading the infection far and wide in the population C) a tendency to die out rather quickly, cease to reproduce, or cause a less severe effect on the host D) a destruction of the host immune system and eventual cancer E) no discoverable relationship with other pathogens in the same or related species
C
Naturally acquired passive immunity would involve the A) injection of vaccine. B) ingestion of interferon. C) placental transfer of antibodies. D) absorption of pathogens through mucous membranes. E) injection of antibodies.
D
Phagocytosis of microbes by macrophages is enhanced by which of the following? A) the binding of antibodies to the surface of microbes. B) antibody-mediated agglutination of microbes. C) the release of cytokines by activated B cells. D) A and B only E) A, B, and C
A
Septic shock, a systemic response including high fever and low blood pressure, can be life threatening. What causes septic shock? A) certain bacterial infections B) specific forms of viruses C) the presence of natural killer cells D) a fever of >103 degrees in adults E) increased production of neutrophils
B
Some viruses can undergo latency, the ability to remain inactive for some period of time. Which of the following is an example? A) influenza, a particular strain of which returns every 10-20 years B) herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host C) Kaposiʹs sarcoma, which causes a skin cancer in people with AIDS, but rarely in those not infected by HIV D) the virus that causes a form of the common cold, which recurs in patients many times in their lives E) myasthenia gravis, an autoimmune disease that blocks muscle contraction from time to time
D
The DGS-like phenotype can be produced in a specific knockout mouse for HA3, a Hox gene. HA3 is known to be involved in developmental regulation in the mouse. Which of the following would be an appropriate test for following the gene in the mouse progeny? A) bone marrow biopsy B) assay for environmental agents known to cause birth defects C) chest X-ray D) measurement of the proportion of CD4 cells to total lymphocytes E) autopsy examination of the thymus
A
The MHC is important in a T cellʹs ability to A) distinguish self from nonself. B) recognize specific parasitic pathogens. C) identify specific bacterial pathogens. D) identify specific viruses. E) recognize differences among types of cancer.
E
The following events occur when a mammalian immune system first encounters a pathogen. Which shows the correct sequence in which they occur? I. Pathogen is destroyed. II. Lymphocytes secrete antibodies. III. Antigenic determinants from pathogen bind to antigen receptors on lymphocytes. IV. Lymphocytes specific to antigenic determinants from pathogen become numerous. V. Only memory cells remain. A) I III II IV V B) III II I V IV C) II I IV III V D) IV II III I V E) III IV II I V
C
The number of MHC protein combinations possible in a given population is enormous. However, an individual in that population has only a couple of MHC possibilities. Why? A) The MHC proteins are made from several different gene regions that are capable of rearranging in a number of ways. B) MHC proteins from one individual can only be of class I or class II. C) Each of the MHC genes has a large number of alleles, but each individual only inherits 2 for each gene. D) Once a B cell has matured in the bone marrow, it is limited to two MHC response categories. E) Once a T cell has matured in the thymus, it can only respond to two MHC categories.
A
These cells are involved in cell-mediated immunity and destroy virally infected cells: A) cytotoxic T cells B) natural killer cells C) helper T cells D) macrophages E) B cells
A
These cells are involved in cell-mediated immunity, and they respond to class I MHC molecule-antigen complexes: A) cytotoxic T cells B) natural killer cells C) helper T cells D) macrophages E) B cells
B
These cells are involved in innate immunity, and a person lacking these cells may have a higher than normal chance of developing malignant tumors: A) cytotoxic T cells B) natural killer cells C) helper T cells D) macrophages E) B cells
E
What accounts for antibody switching (i.e., the switch of one B cell from producing one class of antibody to another antibody class that is responsive to the same antigen)? A) mutation in the genes of that B cell, induced by exposure to the antigen B) the rearrangement of V region genes in that clone of responsive B cells C) a switch in the kind of antigen-presenting cell that is involved in the immune response D) a patientʹs reaction to the first kind of antibody made by the plasma cells E) the shuffling of exons for one C region type to another attached to the V-J transcript
D
What are CD4 and CD8? A) proteins secreted by antigen-presenting cells B) receptors present on the surface of natural killer (NK) cells C) T-independent antigens D) molecules present on the surface of T cells where they enhance cellular interaction E) molecules on the surface of antigen-presenting cells where they enhance B cell activity
D
What are antigens? A) proteins found in the blood that cause foreign blood cells to clump B) proteins embedded in B cell membranes C) proteins that consist of two light and two heavy polypeptide chains D) foreign molecules that trigger the generation of antibodies E) proteins released during an inflammatory response
E
What aspect of the immune response would a patient who has a parasitic worm infection and another patient responding to an allergen such as ragweed pollen have in common? A) Both patients would have an increase in cytotoxic T cell number. B) Both patients would suffer from anaphylactic shock. C) Both patients would risk development of an autoimmune disease. D) Both patients would be suffering from a decreased level of innate immunity. E) Both patients would have increased levels of IgE.
D
What is the primary function of humoral immunity? A) It primarily defends against fungi and protozoa. B) It is responsible for transplant tissue rejection. C) It protects the body against cells that become cancerous. D) It produces antibodies that circulate in body fluids. E) It primarily defends against bacteria and viruses that have already infected cells.
A
When antibodies attack antigens, clumping of the affected cells generally occurs. This is best explained by A) the shape of the antibody with at least two binding regions. B) disulfide bridges between the antigens. C) complement that makes the affected cells sticky. D) bonds between class I and class II MHC molecules. E) denaturation of the antibodies.
A
Which action below is affected by an antihistamine? A) blood vessel dilation B) phagocytosis of antigens C) MHC presentation by macrophages D) the secondary immune response E) clonal selection by antigens
D
Which cells and which signaling molecules are responsible for initiating an inflammatory response? A) phagocytes: lysozymes B) phagocytes: chemokines C) dendritic cells: interferons D) mast cells: histamines E) lymphocytes: interferons
B
Which of the following are T cells of the immune system? A) CD4, CD8, and plasma cells B) cytotoxic and helper cells C) plasma, antigen-presenting, and memory cells D) lymphocytes, macrophages, and dendritic cells E) class I MHC, class II MHC, and memory cells
E
Which of the following are symptoms of inflammation that might appear in such art? A) heat, pain, and redness B) pain and whitening of the surrounding tissue C) swelling and pain D) antibody producing cells E) swelling, heat, redness, and pain
A
Which of the following cell types are responsible for initiating a secondary immune response? A) memory cells B) macrophages C) stem cells D) B cells E) T cells
A
Which of the following could prevent the appearance of the symptoms of an allergy attack? A) blocking the attachment of the IgE antibodies to the mast cells B) blocking the antigenic determinants of the IgM antibodies C) reducing the number of helper T cells in the body D) reducing the number of cytotoxic cells E) reducing the number of natural killer cells
C
Which of the following differentiates T cells and B cells? A) T cells but not B cells are stimulated to increase the rate of their cell cycles. B) Only B cells are produced from stem cells of the bone marrow. C) T cells but not B cells can directly attack and destroy invading pathogens. D) T cells but not B cells have surface markers. E) Only B cells take part in cell-mediated immunity.
D
Which of the following is a characteristic of the early stages of local inflammation? A) anaphylactic shock B) fever C) attack by cytotoxic T cells D) release of histamine E) antibody- and complement-mediated lysis of microbes
B
Which of the following is a pathway that would lead to the activation of cytotoxic T cells? A) B cell contact antigen helper T cell is activated clonal selection occurs B) body cell becomes infected with a virus new viral proteins appear class I MHC molecule-antigen complex displayed on cell surface C) self-tolerance of immune cells B cells contact antigen cytokines released D) complement is secreted B cell contacts antigen helper T cell activated cytokines released E) cytotoxic T cells class II MHC molecule-antigen complex displayed cytokines released cell lysis
D
Which of the following is accounted for by immunological memory? A) the human bodyʹs ability to distinguish self from nonself B) the observation that some strains of the pathogen that causes dengue fever cause worse disease than others C) the ability of a helper T cell to signal B cells via cytokines D) the ancient observation that someone who had recovered from the plague could safely care for those newly diseased E) the ability of the immune system to present antigen fragments in association with MHC antigens
B
Which of the following is not a component of an insectʹs defense against infection? A) enzyme activation of microbe-killing chemicals B) activation of natural killer cells C) phagocytosis by hemocytes D) production of antimicrobial peptides E) a protective exoskeleton
B
Which of the following is not true about helper T cells? A) They function in cell-mediated and humoral responses. B) They recognize polysaccharide fragments presented by class II MHC molecules. C) They bear surface CD4 molecules. D) They are subject to infection by HIV. E) When activated, they secrete cytokines.
C
Which of the following is the last line of defense against an extracellular pathogen? A) lysozyme production B) phagocytosis by neutrophils C) antibody production by plasma cells D) histamine release by basophils E) lysis by natural killer cells
D
Which of the following is the most likely reason that ancient peoples sought to identify inflammation? A) Seeing such signs would be cause for their seeking out a healer in their community. B) Presence of the signs of inflammation in a patient could be a condemnation of the healer. C) The ancients probably knew of plant derivatives that could reduce the pain of inflammation. D) If these signs were present, they would know that healing was taking place; otherwise the patient would likely die. E) The signs of inflammation served as a caution to keep people away from the patient.
D
Which of the following is true of active but not passive immunity? A) acquisition and activation of antibodies. B) proliferation of lymphocytes in bone marrow. C) transfers antibodies from the mother across the placenta. D) requires direct exposure to a living or simulated pathogen. E) requires secretion of interleukins from macrophages.
A
Which of the following is true of the successful development of a vaccine to be used against a pathogen? A) It is dependent on the surface antigens of the pathogen not changing. B) It requires a rearrangement of the B cell receptor antibodies. C) It is not possible without knowing the structure of the surface antigens on the pathogen. D) It is dependent on the pathogen having only one epitope. E) It is dependent on MHC molecules being heterozygous.
D
Which of the following results in long-term immunity? A) the passage of maternal antibodies to a developing fetus B) the inflammatory response to a splinter C) the administration of serum obtained from people immune to rabies D) the administration of the chicken pox vaccine E) the passage of maternal antibodies to a nursing infant
B
Which of the following would be most beneficial in treating an individual who has been bitten by a poisonous snake that has a fast-acting toxin? A) vaccination with a weakened form of the toxin B) injection of antibodies to the toxin C) injection of interleukin-1 D) injection of interleukin-2 E) injection of interferon
D
Which of these molecules is incorrectly paired with a source? A) lysozymeNtears B) interferonsNvirus-infected cells C) antibodiesNB cells D) chemokinesNcytotoxic T cells E) cytokinesNhelper T cells
D
Which statement about the complement system is true? A) These proteins are involved in innate immunity and not acquired immunity. B) These proteins are secreted by cytotoxic T cells and other CD8 cells. C) This group of proteins includes interferons and interleukins. D) These proteins are one group of antimicrobial proteins acting together in cascade fashion. E) These proteins act individually to attack and lyse microbes.
C
Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells? A) B cells confer active immunity; cytotoxic T cells confer passive immunity. B) B cells kill viruses directly; cytotoxic T cells kill virus-infected cells. C) B cells secrete antibodies against a virus; cytotoxic T cells kill virus-infected cells. D) B cells accomplish the cell-mediated response; cytotoxic T cells accomplish the humoral response. E) B cells respond the first time the invader is present; cytotoxic T cells respond subsequent times.
D
Why can normal immune responses be described as polyclonal? A) Blood contains many different antibodies to many different antigens. B) Construction of a hybridoma requires multiple types of cells. C) Multiple immunoglobulins are produced from descendants of a single B cell. D) Diverse antibodies are produced for different epitopes of a specific antigen. E) Macrophages, T cells, and B cells all are involved in normal immune response.
B
bacterium, what is a probable consequence? A) destruction of the bacterium by NK cells B) successful reproduction of the bacterium and continued disease C) removal of the bacterium by dendritic cells D) the individualʹs humoral immunity will immediately take over E) lymphocytes will migrate from the thymus to manage the bacterium