Chapter 11

Question 1

1. [Chapter 11] Which of the following statements is incorrect regarding memory B cells?

a. Memory B cells are maintained for life.
b. In secondary responses, the number of pathogen-specific B cells is about 10Ð100-fold that seen in primary responses.
c. The sensitivity of memory B cells is improved compared with naive B bells because affinity maturation has occurred.
d. Memory B cells express lower levels of MHC class II and B7 than do naive B cells.
e. Memory B cells differentiate into plasma cells more rapidly than do naive B cells.

Answer 1

d. Memory B cells express lower levels of MHC class II and B7 than do naive B cells.

Question 2

2. What would be the outcome if a naive B cell were to bind to pathogen coated with specific antibody made by an effector B cell in a primary immune response using FcgammaRIIB1, and simultaneously bind to the same pathogen using its B-cell receptor?

a. a positive signal leading to the production of low-affinity IgM antibodies
b. a positive signal leading to isotype switching and the production of IgG, IgA, or IgE antibodies
c. a positive signal leading to somatic hypermutation and the production of high-affinity IgM antibodies
d. a negative signal leading to inhibition of the production of low-affinity IgM antibodies
e. a negative signal leading to apoptosis

Answer 2

d. a negative signal leading to inhibition of the production of low-affinity IgM antibodies

Question 3

3. Which of the following explains why the first baby born to a RhD(-) mother and a RhD(+) father does not develop hemolytic disease of the newborn?

a. Fetal erythrocytes do not cross the placenta and therefore do not stimulate an antibody response.
b. The antibodies made by the RhD(-) mother during the first pregnancy are predominantly IgM and have low affinity for the Rhesus antigen.
c. Maternal macrophages in the placenta bind to anti-Rhesus antibodies and prevent their transfer to the fetus.
d. Hemolytic disease of the newborn is a T-cell-mediated disease and maternal T cells do not cross the placenta during pregnancy.
e. The Rhesus antigen is not immunogenic and does not stimulate an antibody response.

Answer 3

b. The antibodies made by the RhD(-) mother during the first pregnancy are predominantly IgM and have low affinity for the Rhesus antigen.

Question 4

4. By which process are fetal erythrocytes destroyed in hemolytic anemia of the newborn?

a. lysis of erythrocytes by cytotoxic T cells
b. lysis of erythrocytes by complement activation
c. clearance of antibody-coated erythrocytes by macrophages in the fetal spleen
d. lysis of erythrocytes by NK cells via antibody-dependent cell-mediated cytotoxicity
e. cytotoxicity caused by major basic protein released from eosinophils

Answer 4

c. clearance of antibody-coated erythrocytes by macrophages in the fetal spleen

Question 5

5. When a naive B cell binds to an IgG:antigen complex on its cell surface using FcgammaRIIB1, while simultaneously binding to the same antigen using membrane-bound IgM, _____.

a. the IgG:antigen complex is endocytosed
b. the B cell becomes anergic
c. the B cell will switch isotype to IgG
d. the B cell undergoes affinity maturation
e. the B cell secretes large amounts of IgM before becoming a memory B cell

Answer 5

b. the B cell becomes anergic

Question 6

6. Original antigenic sin is best described as a phenomenon in which _____.

a. a highly mutable virus gradually escapes from immunological memory and interferes with compensatory immune responses.
b. latent viruses periodically activate effector T cells specific for the original antigen recognized in the primary immune response.
c. the persistence of antigen is necessary to sustain maintenance of immunological memory.
d. memory T cells no longer express the same profile of adhesion molecules and cytokine receptors compared with the original profile of the naive precursor T cell.

Answer 6

a. a highly mutable virus gradually escapes from immunological memory and interferes with compensatory immune responses.

Question 7

7. Imagine a situation in which an individual who has a latent cytomegalovirus (CMV) infection receives a hematopoietic stem-cell transplant. Which of the following is likely to occur?

a. The memory T cells present at the time of transplantation would inhibit activation of newly generated naive T cells.
b. The CMV viral load would increase exponentially, overcoming the host and causing death.
c. The transplant-derived naive T cells would be activated and give rise to memory T cells that would persist and control viral load.
d. There would be a rapid increase in CMV viral load and expansion of T cells bearing CD45RA.

Answer 7

c. The transplant-derived naive T cells would be activated and give rise to memory T cells that would persist and control viral load.

Question 8

8. Which of the following are not a component of immunological memory?

a. effector B cells
b. memory T cells
c. memory B cells
d. long-lived plasma cells

Answer 8

a. effector B cells

Question 9

9. The efficiency and specificity of adaptive immune defenses and immunological memory improve each time a particular pathogen is encountered because _____.

a. of protective immunity
b. effector memory T cells outnumber central memory T cells
c. the half-life of antibodies made in secondary and tertiary immune responses exceeds that of antibodies made in primary immune responses
d. of affinity maturation

Answer 9

d. of affinity maturation

Question 10

10. Unlike naive lymphocytes, memory lymphocytes _____.

a. do not recirculate between the blood and secondary lymphoid organs
b. do not require the receipt of survival signals through their antigen receptors in order to persist
c. are immortal and continue to divide throughout the lifetime of an individual
d. secrete antibody continuously, although at a much lower rate than plasma cells
e. do not express CD27

Answer 10

b. do not require the receipt of survival signals through their antigen receptors in order to persist

Question 11

11. All of the following are ways in which plasma cells differ from memory cells except _____.

a. plasma cells lack surface immunoglobulin
b. cellular morphology
c. plasma cells are CD27-negative
d. plasma cells have undergone isotype switching
e. plasma cells are short-lived

Answer 11

d. plasma cells have undergone isotype switching

Question 12

12. During a secondary immune response, high-affinity IgG antibodies are produced. Which of the following best explains why low-affinity IgM antibodies are not made?

a. Naive pathogen-specific B cells are suppressed by negative signaling through FcgammaRIIB1.
b. Naive pathogen-specific B cells isotype switch and hypermutate much more quickly during secondary immune responses.
c. Memory B cells outnumber naive B cells.
d. Low-affinity IgM antibodies are made only when antigen concentration is exceedingly high.

Answer 12

a.Naive pathogen-specific B cells are suppressed by negative signaling through FcgammaRIIB1.

Question 13

13. Which of the following molecules is not elevated on the surface of memory B cells compared with naive B cells?

a. MHC class II molecules
b. CD45RA
c. antigen receptor
d. CD27
e. co-stimulatory molecules

Answer 13

b. CD45RA

Question 14

14. _____ accounts for the production of different isoforms of the CD45 protein observed in naive, effector, and memory T cells.

a. Isotype switching
b. Affinity maturation
c. Alternative splicing
d. Somatic hypermutation
e. Recirculation to peripheral tissues

Answer 14

c. Alternative splicing

Question 15

15. RhoGAM vaccine is administered to pregnant RhD(-) women so as to _____.

a. stimulate only anti-RhD IgM antibody
b. cause selective removal of anti-RhD memory B cells from the maternal circulation
c. inhibit a primary immune response to RhD antigen and prevent hemolytic anemia of the newborn
d. block transcytosis of IgG to fetal circulation by interfering with FcRn function

Answer 15

c. inhibit a primary immune response to RhD antigen and prevent hemolytic anemia of the newborn

Question 16

16. Identify the mismatched pair.

a. variolation: smallpox
b. Salk vaccine: killed poliovirus
c. vaccinia virus: cowpox
d. rotavirus: segmented DNA virus
e. Sabin vaccine: TVOP

Answer 16

d. rotavirus: segmented DNA virus

Question 17

17. Recombinant DNA technology has been especially useful for the production of _____ that are used in subunit vaccines.

a. viral proteins
b. viral nucleic acids
c. mutated viruses
d. viral polysaccharides
e. infectious particles

Answer 17

a. viral proteins

Question 18

18. With reference to RotaTaq, identify the incorrect statement.

a. It is an attenuated vaccine derived from a human rotavirus, and it is nonpathogenic in humans unless a genetic reversion occurs.
b. It has been genetically engineered to express a variety of human VP4 and VP7 glycoproteins.
c. It is a mixture of five cattle rotaviruses.
d. Standard tissue culture methods are used for its production.
e. It took decades of research to develop this vaccine to an adequate standard.

Answer 18

a.It is an attenuated vaccine derived from a human rotavirus, and it is nonpathogenic in humans unless a genetic reversion occurs.

Question 19

19. Which of the following is(are) example(s) of a subunit vaccine(s)?

a. hepatitis B vaccine and Bexsero
b. Bacille Calmette-Guerin (BCG) vaccine
c. trivalent oral polio vaccine
d. influenza vaccine

Answer 19

a. hepatitis B vaccine and Bexsero

Question 20

20. All of the following are examples of adjuvants, except _____.

a. alum
b. MF59
c. inactivated Bordetella pertussis
d. virosomes
e. RhoGAM

Answer 20

e. RhoGAM

Question 21

21. A newly identified antigen protein of Neisseria meningitidis called fHbp increases virulence by _____.

a. interfering with the alternative pathway of complement activation
b. binding to host-derived heparin
c. increasing the adhesiveness of the bacterium
d. inhibiting phagocytosis
e. inducing inflammation

Answer 21

a. interfering with the alternative pathway of complement activation

Question 22

22. _____ is the approach that mines a pathogen genome to reveal potential antigens and derives clues about cellular location, function, and ability to stimulate protective antibodies based on nucleotide sequence.

a. Conjugation
b. Attenuation
c. Reverse vaccinology
d. Herd immunity
e. Neutralization

Answer 22

c. Reverse vaccinology

Question 23

23. The reason that vaccines against influenza must be administered annually, unlike vaccines against measles, is _____.

a. the antigens that stimulate protection against influenza virus are inside the virion and not on the surface
b. influenza is an RNA virus with a higher mutation rate
c. influenza stimulates T-independent responses that fail to generate memory cells
d. the polysaccharide antigens of influenza stimulate poor immune responses.

Answer 23

b. influenza is an RNA virus with a higher mutation rate

Question 24

24. When a subpopulation of unvaccinated individuals are protected against a pathogen because the vast majority of individuals in the overall population are vaccinated, this is called _____.

a. reverse vaccinology
b. subunit vaccination
c. partial immunization
d. combined immunity
e. herd immunity

Answer 24

e. herd immunity

Question 25

25. After a campus outbreak of Neisseria meningitidis (meningococcal serogroup B), a devastating bacterial disease, which affected at least eight students at Princeton University, the US Food and Drug Administration approved the use of Bexsero to prevent the development of additional cases on that campus. Bexsero is considered to provide broader protective coverage than the US-licenced vaccines conventionally used against this disease. Which of the following methodologies was used to develop Bexsero? a. conjugation of neisserial capsular polysaccharide to tetanus toxoid b. reverse vaccinology c. formalin treatment of secreted toxins d. production of a combination vaccine that includes DTP plus a meningococcal polysaccharide diphtheria toxoid conjugate e. engineering a nonpathogenic cattle strain of N. meningitidis to express antigens associated with pathogenic human strains.

Answer 25

e. engineering a nonpathogenic cattle strain of N. meningitidis to express antigens associated with pathogenic human strains.

Question 26

26. The measles virus is a relatively invariant pathogen that has little, if any, antigenic change. Antibodies made by memory B cells will be just as effective in a recall response as those made in a primary challenge. In fact, antibodies made in secondary immune responses by memory B cells will be more effective because of isotype switching and somatic hypermutation. In contrast, the influenza virus is highly mutable; as a result, new strains emerge each year bearing new epitopes that have not previously stimulated a primary response. Memory response and the suppression of naive B cells restrict antibody production to only those epitopes shared by the infecting strain and the original strain. Over time, the influenza virus will express only a limited number of epitopes that are able to activate memory B cells, and the new epitopes will lack the capacity to stimulate naive B cells. True False

Answer 26

True

Question 27

27. Inactivated virus vaccines are made of virus particles that are not able to replicate because they have been chemically or physically treated (for example by heat) in a way that inactivates the nucleic acid. Examples are Salk polio vaccine, rabies vaccine, and influenza vaccine. True False

Answer 27

True

Question 28

28. Live-attenuated virus vaccines are made of viruses that have lost their pathogenicity and ability to reproduce efficiently in human cells through mutations accumulated as a result of growing the virus in non-human cells. Examples are Sabin polio vaccine (oral), measles vaccine, mumps vaccine, yellow fever vaccine, BCG and Salmonella typhi vaccine, and varicella vaccine. True False

Answer 28

True

Question 29

29. Subunit vaccines are composed only of particular antigenic pathogen components known to induce protective immune responses. Recombinant DNA technology enables the production of antigenic proteins in the absence of other pathogen gene products. Examples are hepatitis B vaccine and Bexsero vaccine. True False

Answer 29

True

Question 30

30. Toxoid vaccines are made from chemically inactivated toxins purified from pathogenic bacteria. Toxin activity is eliminated but antigenic activity is not, so an immune response is generated in the absence of pathological damage. Examples are diphtheria vaccine and tetanus vaccine. True False

Answer 30

True

Question 31

31. Conjugate vaccines are made by covalently coupling antigenic polysaccharide found in bacterial capsules to a carrier protein (often a toxoid). This converts the otherwise T-independent bacterial polysaccharide antigen into a T-dependent antigen. T cells respond to an epitope on the protein carrier, whereas B cells respond to epitopes on the polysaccharide portion of the conjugate. This ensures that T-cell help is provided to B cells making anti-capsule antibodies. Examples include vaccines against Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae. True False

Answer 31

True

Question 32

32. Combination vaccines consist of components that stimulate protective immunity against more than one pathogen. DTP (diphtheria, tetanus, pertussis) vaccine is an example. True False

Answer 32

True

Question 33

33. Bacterial vaccines differ from viral vaccines in that only in bacterial vaccines are _____ used. Selected Answer: a. subunit components b. toxoids, capsular polysaccharides, and capsule:carrier protein conjugates c. whole infectious components d. capsular monosaccharides e. capsule:carrier amino acid conjugates

Answer 33

b. toxoids, capsular polysaccharides, and capsule:carrier protein conjugates

Question 34

34. Reasons complicating the development of vaccines to combat chronic diseases include all below, except_____. a. evasion of the host immune system by the pathogen b. the polymorphic diversity of MHC class I and class II molecules c. the generation of inappropriate immune responses that do not eradicate the pathogen d. survival of the infectious agent for long periods inside the host e. low mutation rates in the pathogen

Answer 34

e. low mutation rates in the pathogen

Question 35

35. On an otherwise uneventful sunny Sunday afternoon, an extremist group enters your city in a large van and drives to the front entrance of the Convention Center, where the annual flower show is taking place. The occupants unload large crates resembling flats of assorted flowers, and then drive off. Within minutes the crates explode, showering the visitors with an opaque powder. Medical teams are called to the scene to care for the injured, and CDC officials wearing levelÊ4 containment suits arrive in a few hours to test the contents of the powder for human pathogens using multiplex PCR methodology (a rapid method for identifying pathogens by their DNA). Which of the following potential bioterrorism agents would pose the most serious threat to those exposed? a. Bacillus anthracis (anthrax) b. Corynebacterium diphtheriae toxin (diphtheria) c. Yersinia pestis (plague) d. variola major (smallpox) e. Clostridium botulinum toxin (botulism)

Answer 35

d. variola major (smallpox)

Question 36

36. In which ways do memory B cells active in a secondary immune response differ from the naive B-cell population activated in a primary immune response? a. The antibody produced is of higher affinity in a secondary immune response; the level of somatic hypermutation is higher in a secondary immune response; and memory B cells express higher levels of MHC class II molecules. b. The frequency of antigen-specific B cells is lower in a secondary immune response. c. Higher levels of IgM are produced in secondary immune responses. d. B cells do not require T-cell help in secondary immune responses. e. Naive B cells express higher levels of co-stimulatory molecules.

Answer 36

a. The antibody produced is of higher affinity in a secondary immune response; the level of somatic hypermutation is higher in a secondary immune response; and memory B cells express higher levels of MHC class II molecules.

Question 37

37. The production of CD45RO results from the removal of _____ during _____ processing. a. domain A; post-translational b. domain A; post-transcriptional c. exons A, B, and C; post-translational d. exons A, B, and C; post-transcriptional e. exon A; post-transcriptional

Answer 37

d. exons A, B, and C; post-transcriptional

Question 38

38. Effector memory cells enter _____, whereas central memory cells enter _____. a. B-cell follicles; T-cell zones of secondary lymphoid tissues b. T-cell zones of secondary lymphoid tissues; B-cell follicles c. secondary lymphoid tissues; primary lymphoid tissues d. T-cell zones of secondary lymphoid tissues; inflamed tissues e. inflamed tissues; T-cell zones of secondary lymphoid tissues

Answer 38

e. inflamed tissues; T-cell zones of secondary lymphoid tissues

Question 39

39. _____ involves deliberate stimulation of the immune system and induction of protective immunity to a particular disease-causing pathogen by mimicking infection in the absence of disease. a. Variolation b. Attenuation c. Vaccination d. Conjugation e. Herd immunity

Answer 39

c. Vaccination

Question 40

40. Inactivation of viruses for vaccine use can be achieved by _____. a. irradiation, heat treatment, and formalin treatment b. cold treatment c. mutation d. neutralization e. ethanol treatment

Answer 40

a. irradiation, heat treatment, and formalin treatment

Question 41

41. The Salk polio vaccine is an inactivated virus vaccine, whereas the Sabin polio vaccine is a live-attenuated virus vaccine. The Salk vaccine should be used for immunocompromised individuals. Live attenuated vaccines carry a risk of mutational reversion in an immunocompromised host to a more virulent, disease-causing strain. This occurs because the virus is able to replicate at higher levels and acquire a significant number of mutations, some of which may lead to reversion to a pathogenic strain. True False

Answer 41

True

Question 42

42. Variolation and vaccination are both procedures used to confer immunological protection against the smallpox virus, variola. They both use live virus and stimulate humoral and cell-mediated immune responses against the smallpox virus. Variolation, a method used for only a short period in the 18th and 19th centuries because of the risk of developing smallpox, used dried pustules derived from humans exhibiting relatively mild symptoms of smallpox infection. Vaccination, a safer alternative causing only mild infection, used dried pustules from cows infected with cowpox. True False

Answer 42

True

Question 43

43. Vaccinia and variola have some viral surface antigens in common. Some of the antibodies made against cowpox surface antigens during immunization are able to bind to shared surface antigens also expressed on the surface of the smallpox virus. Through neutralization, these anti-cowpox antibodies are able to bind to and prevent the entry of smallpox into host cells if the host is infected naturally with the smallpox virus. True False

Answer 43

True

Question 44

44. Example(s) of inactivated virus vaccine(s) is(are) _____. a. Sabin polio vaccine b. influenza and rabies vaccines c. mumps vaccine d. hepatitis B vaccine

Answer 44

b. influenza and rabies vaccines

Question 45

45. For a viral subunit vaccine to be effective, except _____. a. B cells must be activated b. cytotoxic T and NK cells must be activated c. neutralizing antibodies must be induced d. CD4 TFH cells must be activated e. it must be derived from viral surface components.

Answer 45

b. cytotoxic T and NK cells must be activated

Question 46

46. A conjugate vaccine is one that couples _____ to _____ so as to stimulate T-dependent antibody responses. a. polysaccharide; a protein carrier b. a protein carrier; irradiated DNA c. protein carrier; toxoids d. adjuvant; toxoids e. polysaccharide; filamentous hemagglutinin

Answer 46

a. polysaccharide; a protein carrier

Question 47

47. _____ vaccines are the most effective at evoking memory responses against a virus in an immunized host. a. Conjugate b. Subunit c. Killed d. Live Attenuated e. Toxoid

Answer 47

d. Live-attenuated

Question 48

48. Which of the following vaccines is least likely to pose a risk in an individual with an immunodeficiency? a. Sabin polio vaccine b. measles vaccine c. Hepatitus B d. vaccinia vaccine e. yellow fever vaccine

Answer 48

c. Hepatitis B

Question 49

49. Approximately one-quarter of individuals infected with hepatitis C _____. a. develop a chronic infection of hepatocytes b. are at risk of developing liver cancer c. experience episodes of liver destruction and regeneration d. require a liver transplant e. mount an effective immune response and eradicate the virus

Answer 49

e. mount an effective immune response and eradicate the virus

Question 50

50. An adjuvant enhances the effectiveness of vaccines by inducing the expression of _____ on ________. Selected Answer: a. co-stimulatory molecules; dendritic cells b. CD28; macrophages c. MHC class II molecules; T cells d. T-cell receptor; T cells e. immunoreceptor tyrosine-based activation motifs; dendritic cells

Answer 50

a. co-stimulatory molecules; dendritic cells

Question 51

51. Tim Smith, aged 16 years, was hit by a car while riding his motorcycle. At the hospital he showed only minor abrasions and no bone fractures. He was discharged later that day. In the morning he experienced severe abdominal pain and returned to the hospital. Examination revealed tachycardia, low blood pressure, and a weak pulse. He received a blood transfusion without improvement. Laparoscopic surgery confirmed peritoneal hemorrhage due to a ruptured spleen. In addition to a splenectomy, which of the following treatments would be administered? a. plasmapheresis to remove autoantibodies (antibodies generated against self constituents) b. regular intravenous injections of gamma globulin c. vaccination and regular boosters with capsular polysaccharides from pathogenic pneumococcal strains d. booster immunization with DTP (diphtheria toxoid, killed Bordetella pertussis, and tetanus toxoid) e. regular blood transfusions

Answer 51

c. vaccination and regular boosters with capsular polysaccharides from pathogenic pneumococcal strains

Question 52

52. Jenny Smith was five months pregnant when she stepped on a rusty piece of scrap metal while hauling rotted wood from a dilapidated shed in her garden. The sliver of metal cut through her sneaker and pierced her heel deeply. Her physician gave her a tetanus booster. When baby was born she decided to breastfeed. If the baby antibodies were tested for specificity to tetanus 2 months after birth, what would be the expected finding? a. the presence of anti-tetanus toxoid IgA antibodies b. the presence of anti-tetanus toxoid IgM antibodies c. the presence of anti-tetanus toxoid IgG antibodies d. the presence of IgM antibody specific for Clostridium tetani cell-wall components e. the presence of IgG antibody specific for Clostridium tetani cell-wall components

Answer 52

c. the presence of anti-tetanus toxoid IgG antibodies

Question 53

53. There is no link between vaccines and autism (or Autism spectrum disorder (ASD)). Some people have had concerns that ASD might be linked to the vaccines children receive, but studies have shown that there is no link between receiving vaccines and developing ASD. In 2011, an Institute of Medicine (IOM) reportÊon eight vaccines given to children and adults found that with rare exceptions, these vaccines are very safe. True False

Answer 53

True

Question 54

54. Vaccine ingredients do not cause autism [or Autism spectrum disorder (ASD)]. One vaccine ingredient that has been studied specifically isÊthimerosal, a mercury-based preservative used to prevent contamination of multidose vials of vaccines. Research shows that thimerosal does not cause ASD. In fact, a 2004 scientific reviewÊby the Institute of Medicine (IOM) concluded that "the evidence favors rejection of a causal relationship between thimerosal-containing vaccines and autism." Since 2003, there have beenÊnine CDC-funded or conducted studiesÊthat have found no link between thimerosal-containing vaccines and ASD, as well as no link between the measles, mumps, and rubella (MMR) vaccine and ASD in children. True False

Answer 54

True

Question 55

55. A 2013 CDC study added to the research showing that vaccines do not cause (or Autism spectrum disorder (ASD)). The study looked at the number of antigens (substances in vaccines that cause the body immune system to produce disease-fighting antibodies) from vaccines during the first two years of life. The results showed that the total amount of antigen from vaccines received was the same between children with ASD and those that did not have ASD. True False

Answer 55

True