Chapter 43

24) How is a viral antigen, like EBV, recognized by T cells?

A) An antigen fragment is presented within class I MHC to the T cell receptor.

29) What major advantage is conveyed by having a system of adaptive immunity?

A) It enables a rapid defense against an antigen that has been previously encountered.

50) 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, but bacteria lack MHC molecules

26) ________ is a characteristic of adaptive immunity but not innate immunity.

A) Memory

9) Use the graphs to answer the following question. Mutant fruit flies that make only one antimicrobial peptide were tested for survival after infection with Neurospora crassa fungi or with Micrococcus luteus bacteria. The results shown in the graphs support the hypothesis that ________.

A) adding the defensin gene to such mutants protects them from death by bacterial infection

7) Septic shock, a systemic response including high fever and low blood pressure, is a response to ________.

A) certain bacterial infections

54) Which of the following components of the immune system destroys bacteria by punching holes in the wall of the bacteria?

A) complement protein

49) A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin, Bob), even though Jane has previously given blood for one of Bob's needed transfusions, because ________.

A) even though Jane's blood type is a match to Bob's, her major histocompatibility (MHC) proteins may not be a match

5) Inflammatory responses typically include ________.

A) increased activity of phagocytes in an inflamed area

10) A boy falls while riding his bike. A scrape on his hand almost immediately begins to bleed and becomes red, warm, and swollen. What response is occurring?

A) inflammatory response

1) Innate immunity ________.

A) is the first, and most general, mechanism of protection against pathogens

21) An immunoglobulin (Ig) molecule, of any class, with regions symbolized as C or V, H or L, has a light chain made up of ________.

A) one C region and one V region

42) Phagocytosis of microbes by macrophages is enhanced by ________. I) the binding of antibodies to the surface of microbes II) antibody-mediated opsonization of microbes III) the release of cytokines by activated B cells

A) only I and II

61) If a person is prone to allergies, what treatment could redirect their immune response to help prevent future allergic reactions?

A) stimulating activated B cells to switch antibody production from class IgE to class IgM

41) When antibodies bind antigens, the clumping of antigens results from ________.

A) the antibody having at least two binding regions

46) For the successful development of a vaccine to be used against a pathogen, it is necessary that ________.

A) the surface antigens of the pathogen stay the same

2) A strain of fruit fly lacks the ability to produce Dicer-2 protein. You might expect this strain to be more susceptible to ________ infections.

A) viral

4) Which of the following statements is not true?

B) A lymphocyte has receptors for multiple different antigens.

8) ________ are cells of the mammalian innate immune response that help destroy tumors.

B) Natural killer cells

6) ________ are receptor molecules on mammalian cells that recognize macromolecules that are present in or on certain groups of pathogens.

B) Toll-like receptors

16) You and a friend were in line for a movie when you noticed the woman in front of you sneezing and coughing. Both of you were equally exposed to the woman's virus, but over the next few days, only your friend acquired flu-like symptoms and was ill for almost a week before recovering. Which one of the following is a logical explanation for this?

B) You had an immunological memory of that virus.

1) Which of these is not part of insect immunity?

B) activation of natural killer cells

20) Clonal selection is an explanation for how ________.

B) an antigen can provoke production of high amounts of specific antibodies

35) Select the pathway that would lead to the activation of cytotoxic T cells.

B) body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface

39) T cells of the immune system include ________.

B) cytotoxic and helper cells

57) The ability of some viruses to remain inactive (latent) for a period of time is exemplified by ________.

B) herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host

62) In a humoral or antibody-mediated immune response, specific B cells are stimulated by helper T cells to transform into plasma cells that secrete antibodies. What would be an important feature added to the plasma cells during this transition process that allows them to better perform their function?

B) increased rough endoplasmic reticulum for greater antibody production

45) An individual who has been bitten by a poisonous snake that has a fast-acting toxin would likely benefit from ________.

B) injection of antibodies to the toxin

6) Vaccination increases the number of

B) lymphocytes with receptors that can bind to the pathogen.

59) Which of the following would help a virus avoid triggering an effective adaptive immune response? I) having frequent mutations in genes for surface proteins II) building the viral shell from host proteins III) producing proteins very similar to those of other viruses IV) infecting and killing helper T cells

B) only I, II, and IV

33) Which of the following proteins can be classified as immunoglobulins? I) T cell receptors II) B cell receptors III) Antigens

B) only II

15) Mucus occurs in both the respiratory and digestive tracts. What is its main immunological function?

B) physically trapping of pathogens

53) Which of the following is crucial to activation of the adaptive immune response?

B) presentation of MHC (major histocompatibility complex)-antigen complex on a cell surface

5) Which of the following should be the same in identical twins?

B) the set of MHC molecules produced

52) Which of the following should be the same in identical twins?

B) the set of major histocompatibility (MHC) molecules produced

25) Vaccination offers protection against future exposure to pathogens because it ________.

B) triggers clonal expansion of lymphocytes

3) Which statement best describes the difference between responses of effector B cells (plasma cells) and those of cytotoxic T cells?

C) B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

23) Use the following information to answer the question(s) below. An otherwise healthy student in your class was infected with EBV (the virus that causes infectious mononucleosis) when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. When she is exposed to EBV again later in life, she does not get sick or have any symptoms of mononucleosis. Which of the following statements explains why your class mate does not exhibit symptoms of EBV infection?

C) Memory T cells quickly recognized the virus upon the second exposure and destroyed the virally infected cells.

60) Which of the following is the best definition of autoimmune disease?

C) a condition in which self molecules are treated as nonself (loss of self-tolerance)

13) The complement system is ________.

C) a group of proteins that act together in a cascade fashion

58) A patient complaining of watery, itchy eyes and sneezing after being given a flower bouquet as a birthday gift should first be treated with ________.

C) antihistamines

19) A newborn who is accidentally given a drug that destroys the thymus would most likely ________.

C) be unable to differentiate and mature T cells

30) Which of the following are similarities between B cells and T cells? I) They both recognize antigen using immunoglobulin receptors. II) Both B cells and T cells undergo clonal selection after encountering an antigen. III) B cells and T cells both maintain an immunological memory of previously encountered antigens.

C) both II and III

48) The number of major histocompatibility (MHC) protein combinations possible in a given population is enormous. However, an individual in that diverse population has a far more limited array of MHC molecules because ________.

C) each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene

4) The cells and signaling molecules involved in the initial stages of the inflammatory response are ________.

C) mast cells and histamines

31) A certain cell type has existed in the blood and tissue of its vertebrate host's immune system for over 20 years. One day, it recognizes a newly arrived antigen and binds to it, subsequently triggering a secondary immune response in the body. Which of the following cell types most accurately describes this cell?

C) memory cell

38) CD4 and CD8 are ________.

C) molecules present on the surface of T cells where they interact with major histocompatibility (MHC) molecules

32) Which of the following statements about epitopes are correct? I) B cell receptors bind to epitopes. II) T cell receptors bind to epitopes. III) There can be 10 or more different epitopes on each antigen. IV) There is a one-to-one correspondence between antigen and epitope.

C) only I, II, and III

28) Which of the following statements are fundamental to the clonal selection theory of how the adaptive immune system functions? I) Each lymphocyte has a unique membrane receptor that recognizes one antigen. II) When the lymphocyte binds an antigen, it is activated and begins dividing to form many identical copies of itself. III) Cloned lymphocytes have slight differences and are selected by the spleen for removal if they do not bind an antigen. IV) Cloned cells descend from an activated lymphocyte and persist even after the pathogen is eliminated.

C) only I, II, and IV

27) Lymphocytes mature in the ________. I) spleen II) thymus III) bone marrow

C) only II and III

34) What type of immunity is associated with breast feeding?

C) passive immunity

43) Naturally acquired passive immunity can result from the ________.

C) placental transfer of antibodies

7) Which of the following would not help a virus avoid triggering an adaptive immune response?

C) producing proteins very similar to those of other viruses

44) Jenner's successful use of cowpox virus as a vaccine against the smallpox virus was due to the fact that ________.

C) there are some epitopes (antigenic determinants) common to both pox viruses

2) An epitope associates with which part of an antigen receptor or antibody?

C) variable regions of a heavy chain and light chain combined

3) Vertebrate immune cells, which are phagocytic, include ________. I) neutrophils II) macrophages III) dendritic cells IV) natural killer cells

D) I, II, and III

36) Arrange in the correct sequence these components of the mammalian immune system as it first responds to a pathogen. I) Pathogen is destroyed. II) Lymphocytes secrete antibodies. III) Antigens from a pathogen bind to antigen receptors on lymphocytes. IV) Lymphocytes specific to antigens from a pathogen become numerous. V) Only memory cells remain.

D) III → IV → II → I → V

14) Bacteria entering the body through a small cut in the skin ________.

D) activate a group of proteins called complement

56) A patient who has a high level of mast cell activity, dilation of blood vessels, and acute drop in blood pressure is likely suffering from ________.

D) anaphylactic shock immediately following exposure to an allergen

51) Which of the following components of the immune system destroys cancerous cells by punching holes in plasma membranes and triggering apoptosis?

D) cytotoxic T cells

40) B cells interacting with helper T cells are stimulated to differentiate when ________.

D) helper T cells release cytokines

11) Acidity in human sweat is an example of ________.

D) innate immunity

37) A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to ________.

D) interact with a class II MHC-antigen complex

55) Yearly vaccination of humans for influenza viruses is necessary because ________.

D) rapid mutation in flu viruses alters the surface proteins in infected host cells

17) Within a differentiated B cell, the rearrangement of DNA sequences between variable regions and joining regions is accomplished by a(n)________.

D) recombinase

18) Clonal selection and differentiation of B cells activated by antigen exposure leads to the production of ________.

D) short-lived plasma cells that secrete antibodies for the antigen

22) Immunological memory accounts for ________.

D) the ancient observation that someone who had recovered from the plague could safely care for those newly diseased

47) The switch of one B cell from producing one class of antibody to another class of antibody that is responsive to the same antigen is due to ________.

D) the rearrangement of immunoglobulin heavy-chain C region DNA

12) The eyes and the respiratory tract are both protected against infections by ________.

D) the secretion of lysozyme onto their surfaces