Deck 11: Immunological Memory and Vaccination

Question 1

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 10-100-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

Question 2

Identify three reasons why memory B cells respond more forcefully and effectively during secondary immune responses than naive B cells during primary immune responses.

Answer 2

(i)Memory B cells bearing pathogen-specific immunoglobulin are more numerous than naive B cells. (ii)Memory B cells are activated more easily than naive B cells. (iii)Memory B cells have already undergone isotype switching,somatic hypermutation,and affinity maturation.

Question 3

Explain (A)why only memory B cells,and not naive B cells,participate in secondary immune responses to particular pathogens,and (B)why this is advantageous to the host.

Answer 3

A.Naive B cells carry the inhibitory Fc receptor FcγRIIB1.Complexes composed of antigen and IgG produced in the primary response,or by reactivated memory cells,cross-link FcγRIIB1 and the B-cell receptor,which suppresses naive B-cell activation.In contrast,memory B cells do not carry this receptor,and so are not inhibited in this way. B.The suppression of naive B cells means that only reactivated memory B cells (which have already undergone isotype switching and somatic hypermutation)make antibodies.Thus all the antibodies made are of high affinity and are primarily of the IgG,IgA,or IgE isotype.Suppression of naive B cells eliminates repetition of the events that took place in the primary immune response,which would,if not inhibited,lead to the production of low-affinity IgM antibodies rather than high-affinity,isotype-switched antibodies that are more effective at removing the pathogen.

Question 4

_____ 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.

Question 5

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.

Question 6

a naive B cell binds to an IgG:antigen complex on its cell surface using FcγRIIB1,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.

Question 7

Explain why memory B cells are more efficient at responding to pathogens than are naive B cells.

Question 8

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.

Question 9

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 FcγRIIB1,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.

Question 10

Memory B cells differ from memory T cells in the following ways.(Select all that apply.)

A)They suppress naive antigen-specific lymphocytes during secondary immune responses.
B)They recirculate only through secondary lymphoid organs.
C)They secrete their antigen receptors throughout their life-span.
D)They generate long-lived clones of memory cells during the primary immune response.

Question 11

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.

Question 12

Explain briefly how immunological memory operates in (A)the short term and (B)the long term.

Question 13

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.

Question 14

"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.

Question 15

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.

Question 16

four reasons why secondary immune responses are faster and more effective than primary immune responses.

Question 17

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.

Question 18

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.

Question 19

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.

Question 20

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 FcγRIIB1.
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.

Question 21

Bacterial vaccines differ from viral vaccines in that only in bacterial vaccines are _____ used.(Select all that apply.)

A)subunit components
B)toxoids
C)whole infectious components
D)capsular polysaccharides
E)capsule:carrier protein conjugates.

Question 22

Explain why the DTP vaccine stimulates a much stronger protective immunity than does the DT vaccine.

Question 23

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.

Question 24

Reasons complicating the development of vaccines to combat chronic diseases include _____.(Select all that apply.)

A)evasion of the host's 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)high mutation rates in the pathogen.

Question 25

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.

Question 26

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.

Question 27

Why is determining the genome sequences of human pathogens important in the development of new and more effective vaccines?

Question 28

Identify three characteristics of smallpox that aided in the global eradication of this disease through a rigorous vaccination program.

Question 29

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.

Question 30

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.

Question 31

Which of the following is an example of a subunit vaccine? (Select all that apply.)

A)hepatitis B vaccine
B)Bacille Calmette-Guérin (BCG)vaccine
C)trivalent oral polio vaccine
D)influenza vaccine
E)Bexsero^®.

Question 32

What is the risk to a population that reduces its use of particular vaccines over a period?
B.Identify two cases in which this has happened and the underlying reason for distrust in the benefit of the vaccine.

Question 33

Differentiate between the following types of vaccine and give an example of each: (A)inactivated virus vaccines; (B)live-attenuated virus vaccines; (C)subunit vaccines; (D)toxoid vaccines; (E)conjugate vaccines; and (F)combination vaccines.

Question 34

What risks are associated with live-attenuated virus vaccines?

Question 35

Explain why the suppression of naive B cells in secondary immune responses is advantageous for fighting the measles virus but disadvantageous for fighting the influenza virus.

Question 36

All of the following are examples of adjuvants except _____.

A)alum
B)MF59
C)inactivated Bordetella pertussis
D)virosomes
E)RhoGAM.

Question 37

_____ is the approach that mines a pathogen's 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.

Question 38

RhoGAM is administered to pregnant RhD^- women so as to _____.(Select all that apply.)

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
D)block transcytosis of IgG to fetal circulation by interfering with FcRn function
E)prevent hemolytic anemia of the newborn

Question 39

Explain the challenges associated with generating effective vaccines against encapsulated bacteria.
B.How have these challenges been overcome?
C.Explain the cellular events required for the production of protective IgG antibodies against bacterial polysaccharide components and the development of memory.

Question 40

Explain the difference between the Rotarix and the RotaTeq vaccines used to protect against rotavirus infections.
B.Which vaccine provides broader protection?
C.Why is this important?

Question 41

_____ 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.

Question 42

Fill in the blanks.
A.Cross-linking ________ and ________ on a ______ B cell by a specific antigen:IgG complex renders the B cell anergic.
B.Treatment based on the above phenomenon is used to prevent hemolytic disease of the newborn,which can occur in families in which the mother is ______ and the father _______.

Question 43

In the context of providing protection against smallpox,describe (A)the similarities and (B)the differences between variolation and vaccination.(C)Now explain the mechanisms by which immunization with vaccinia virus provides protection against smallpox.

Question 45

Inactivation of viruses for vaccine use can be achieved by _____.(Select all that apply.)

A)irradiation
B)heat treatment
C)mutation
D)neutralization
E)formalin treatment.

Question 46

An adjuvant enhances the effectiveness of vaccines by inducing the expression of _____ on ________.

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.

Question 47

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 level 4 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).

Question 49

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.

Question 50

What is the difference between the Salk and Sabin polio vaccines?
B.Which one should be used for an individual who has an immunodeficiency disease,and why?

Question 51

Which of the following explain why infections with influenza virus erode immunological memory over time? (Select all that apply.)

A)Influenza is a highly mutable virus that changes its epitope composition.
B)A compensatory immune response to new epitope variants is suppressed in naive B cells.
C)The antibody response is directed only toward new epitope variants,resulting in a decreased memory response.
D)Cross-linking of B-cell receptor and FcγRIIB1 on memory B cells induces anergy.
E)Naive B cells are suppressed by cytokines made by memory B cells.

Question 52

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.

Question 53

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)hepatitis B vaccine
D)vaccinia vaccine
E)yellow fever vaccine.

Question 54

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.

Question 55

Which of the following explain why the safety standards for vaccines are set higher than those for drugs? (Select all that apply.)

A)Some vaccines can induce a disease state.
B)Vaccines provoke side-effects in otherwise healthy children.
C)Vaccines are much more costly to develop and test than most drugs.
D)Vaccination programs are targeted at large populations.
E)Subunit vaccines can potentially integrate into the host genome and activate host oncogenes,leading to the development of cancer.

Question 56

Naive T cells do not express _____.(Select all that apply.)

A)CD25
B)CD45RA
C)CCR7
D)IFN-γ
E)FasL.

Question 57

An example of an inactivated virus vaccine is _____.(Select all that apply.)

A)Sabin polio vaccine
B)influenza vaccine
C)mumps vaccine
D)hepatitis B vaccine
E)rabies vaccine.

Question 58

_____ 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.

Question 59

An example of a live-attenuated virus vaccine is _____.(Select all that apply.)

A)vaccinia
B)Salk polio vaccine
C)measles vaccine
D)yellow fever vaccine
E)rabies vaccine.

Question 60

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.

Question 61

Jenny O'Mara 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 Jenny's baby was born she decided to breastfeed.If the baby's 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.
ANSWERS

Question 62

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

Question 63

B cells are activated by CD4 T_H2 cells only if both cell types recognize the same antigen.The same epitope,however,does not need to be shared for recognition.
A.Discuss why this characteristic is important in vaccine design.
B.Provide an example of a conjugate vaccine used to stimulate the synthesis of IgG antibody against Haemophilus influenzae B polysaccharide.