Deck 16: The Immune System: Adaptive Immunity

Question 1

The immunoglobulin superfamily of proteins includes

A) immunoglobulins only.
B) immunoglobulins, major histocompatibility complex, and B- and T-cell receptors.
C) major histocompatibility complex and B- and T-cell receptors only.
D) IgA, IgG, IgM, IgE, and IgD only.

Answer 1

B

Question 2

What is the function of an antigen-presenting cell (APC)?

A) An APC presents antigen to macrophages to stimulate the synthesis of antibodies.
B) An APC presents antigen to B cells to stimulate the formation of memory B cells.
C) An APC presents antigen to memory T cells to stimulate the synthesis of cytokines.
D) An APC presents antigen to helper T cells to activate the T cells during a cellular response.

Answer 2

D

Question 3

Which of the following scenarios is an example of an allotypic difference?

A) A single amino acid change gives rise to a new form of IgG antibody in humans.
B) Humans and dogs have slightly different immunoglobulins.
C) A human is able to generate antigen specificity by rearranging genes.
D) There are five major classes of immunoglobulins within an individual.

Answer 3

A

Question 4

When comparing the primary and secondary immune responses,which of the following is true?

A) IgM titer levels are much higher during a secondary immune response.
B) IgG titer levels are much higher during a secondary immune response.
C) IgM titer levels are higher than IgG titer levels during the primary immune response.
D) IgM titer levels are higher than IgG titer levels during the secondary immune response.

Question 5

The figure shown illustrates a bacterial cell that

A) acts as an antigen.
B) is broken down into many antigens.
C) is producing antibodies in response to antigens.
D) has a single epitope.

Question 6

Which of the following cell types is considered a "nonprofessional" antigen-presenting cell?

A) fibroblast
B) macrophage
C) dendritic cell
D) B cell

Question 7

IgG,IgA,IgM,IgD,and IgE are all examples of

A) antigens.
B) idiotypes.
C) isotypes.
D) allotypes.

Question 8

This figure shows the structure of an ________ antibody.

A) IgG
B) IgA
C) IgM
D) IgE

Question 9

Which of the following statements is an example of a situation in which cross-protection will occur?

A) A vaccine is administered for one of two viruses that share epitopes.
B) A single virus triggers a response from both B cells and T cells.
C) An antigen forms a cross-link between two antibodies.
D) A combination vaccine is administered to provide protection against three viruses.

Question 10

Which of the following would you expect to elicit the largest production of antibodies?

A) haptens floating freely within plasma
B) a complex protein with many different epitopes
C) a polysaccharide with several identical segments
D) a small lipid

Question 11

How would you expect an injection of killed or attenuated Salmonella typhi,the causative agent of typhoid fever,to protect an individual?

A) The injection would cause the individual to have a mild case of typhoid fever, but would protect against future cases of typhoid fever.
B) The injection would provide antigens recognizable by the immune system and memory cells would form to prevent typhoid fever in the future.
C) The injection would provide cross-protection to prevent several diseases caused by different bacteria.
D) The injection would provide the individual with premade antibodies capable of binding to and inactivating Salmonella typhi.

Question 12

Which of the following accurately describes how a foreign molecule leads to the production of antibody?

A) Individual epitopes on an antigen are recognized and a single antibody is produced for each epitope.
B) The immune system recognizes whole microbes and responds by secreting a single antibody against the microbe.
C) The immune system recognizes individual haptens on an antigen and secretes several antibodies directed against that hapten.
D) Groups of epitopes on an antigen are recognized and a single antibody is produced for each group.

Question 13

What step would have preceded the figure shown?

A) The B cell would have recognized antigen bound to an antigen-presenting cell.
B) The T cell would have recognized antigen bound to an antigen-presenting cell.
C) The B cell would have gone through clonal expansion.
D) The T cell would have differentiated into plasma cells.

Question 14

The figure shown illustrates clonal expansion of activated B cells.What are the two cell types produced by this cell line?

A) plasma cells and memory B cells
B) antigen-presenting cells and memory T cells
C) activated T cells and plasma cells
D) memory B cells and dendritic cells

Question 15

Clonal expansion of B cells occurs when a(n)

A) antigen-presenting cell binds to a single B cell.
B) helper T cell secretes antibody onto a single B cell.
C) single B cell becomes activated when its receptor binds to a single epitope.
D) memory B cell attaches onto an antigen-presenting cell.

Question 16

Which of the following statements correctly describes the molecules that elicit an immune response?

A) Antigens are small molecules that must be bound to an immunogen to elicit an immune response.
B) Small segments of an antigen that elicit an immune response are called epitopes.
C) Haptens are proteins that elicit the synthesis of antibodies and are also known as antigens.
D) Immunogens are small segments of antigens that are recognized by the immune system.

Question 17

A newborn receives passive immunity through

A) IgG.
B) IgM.
C) IgD.
D) IgE.

Question 18

A microbe is ingested and broken into fragments by an antigen-presenting cell (APC).Which of the following would you expect to occur?

A) B cells will bind to antigens on the surface of the APC.
B) B cells will release cytokines to activate T cells.
C) Plasma cells will release cytokines to activate the APC.
D) T cells will bind to antigens on the surface of the APC.

Question 19

The antigen-binding site on an antibody

A) is composed of light chains only.
B) contains constant amino acid sequences within each class.
C) contains highly variable amino acid sequences.
D) is composed of heavy chains only.

Question 20

Which two antibody classes are displayed on the surface of naïve B cells?

A) IgG and IgD
B) IgE and IgD
C) IgE and IgM
D) IgM and IgD

Question 21

Antigen bound by the molecule shown would be recognized by ________ cells.

A) TC
B) TH₂
C) TH₁7
D) B

Question 22

Which of the following statements accurately describes how memory B cells become activated during the secondary immune response?

A) Memory B cells present antigen bound to MHC II and bind to TH cells.
B) Memory B cells respond to soluble IL-4 and IL-6 without direct contact with TH cells.
C) Memory B cells must bind IgM antibody on activated B cells.
D) Memory B cells use CD40 surface proteins to attach to CD40 ligands on TH cells.

Question 23

The direct consequence of a CD40 protein on a B cell binding to a CD40 ligand on a T cell is

A) initiation of an intracellular signal required for B cell activation.
B) heavy-chain class switching in the B cell.
C) release of IL-2 from the T cell.
D) release of perforins and granzymes from the T cell.

Question 24

The process illustrated in this figure is best described as

A) capping.
B) T-cell-dependent activation.
C) class switching.
D) clonal selection.

Question 25

Almost 95% of T cells entering the thymus die when apoptosis is triggered during

A) positive selection.
B) negative selection.
C) antibody production.
D) MHC recognition.

Question 26

T cells capable of killing virus-infected and cancer cells are known as ________ cells.

A) TC
B) TH₂
C) TH₁₇
D) TH₁

Question 27

T-cell receptors (TCRs)are only able to bind

A) peptides.
B) lipids.
C) polysaccharides.
D) DNA.

Question 28

How are memory B cells able to persist for many years?

A) Memory B cells are continuously stimulated by cytokines released from helper T cells.
B) Memory B cells undergo hypermutation, which allows them to survive indefinitely.
C) Memory B cells use gene rearrangement to prevent apoptosis from occurring.
D) Memory B cells with receptors that match with antigen produce anti-apoptosis protein.

Question 29

Which of the following would most directly eliminate an intracellular pathogen such as a virus?

A) production of antibody
B) activation of B cells
C) activation of cytotoxic T cells
D) activation of helper T cells

Question 30

MHC molecules are required for

A) B cell activation.
B) phagocytosis of microbes.
C) T cell activation.
D) proteasome degradation of viruses.

Question 31

T cells that secrete IL-4,IL-5,and IL-6 and that play a major role in helping B cells are known as ________ cells.

A) Treg
B) TH₂
C) TH₁
D) TH0

Question 32

Why does B-cell proliferation and differentiation often require assistance from helper T cells?

A) Capping does not occur unless epitopes are found in multiple copies.
B) B cells require antigen presentation by helper T cells.
C) Microbes often destroy B-cell receptors and then B cells require help from T cells.
D) Helper T cells are required to move epitopes closer together for capping by B cells.

Question 33

What is the function of class II MHC molecules?

A) Class II MHC is used to present intracellular antigen to CD8 cells.
B) Class II MHC is used to present intracellular antigen to CD4 cells.
C) Class II MHC is used to present extracellular antigen to CD8 cells.
D) Class II MHC is used to present extracellular antigen to CD4 cells.

Question 34

The molecule indicated on this illustration of the first signal during the activation of a cytotoxic T cell (TC)must be

A) Class I MHC.
B) Class II MHC.
C) a CD8 molecule.
D) a B7 protein.

Question 35

Why are cytotoxic T (TC)cells more effective than antibodies at clearing viral infections?

A) TC cells are able to recognize free viral particles as they circulate through lymph nodes.
B) Antibodies bind weakly to antigen-MHC I complexes on antigen-presenting cells.
C) Antibodies are only able to bind to extracellular antigen, and viruses tend to be intracellular.
D) TC cells are activated more strongly than B cells by cytokines released by helper T cells.

Question 36

Class switching is the process in which

A) B cells switch from producing IgM of IgD to producing IgE, IgG, or IgA.
B) formed IgM antibody pentamers break apart into IgM monomers.
C) antibody released from the surface of a B cell switches to a different heavy chain.
D) higher-affinity antibodies are produced upon repeated exposure to the same antigen.

Question 37

The second signal required for TC activation is

A) binding of a CD28 molecule on the T cell to a B7 protein on an antigen-presenting cell.
B) secretion of the cytokine IL-2 from a TH₁ cell.
C) binding of a CD8 molecule on the T cell to an antigen-MHC I complex on an antigen-presenting cell.
D) secretion of the cytokine IL-1 from a TH0 cell.

Question 38

If you had a box of 200 beads that were different shapes and you randomly chose and linked together 3 beads,you would be performing a process analogous to the way

A) T cells are able to use 200 genes to produce 3 receptor types.
B) 200 B cells are able to produce 3 different antibodies.
C) antigens are processed by antigen-presenting cells.
D) antibody diversity is created within our bodies.

Question 39

The cell indicated on this illustration has the surface molecule

A) CD4.
B) Class I MHC.
C) Class II MHC.
D) CD8.

Question 40

Individuals with bare lymphocyte syndrome lack MHC II proteins.Which of the following could still occur in an individual lacking MHC II proteins?

A) Helper T cells could use T-cell receptors to interact with macrophages.
B) B cells could produce IgM antibodies.
C) Cytotoxic T cells could become activated.
D) B cells could undergo class switching independently.

Question 41

Rebecca developed measles as a young child.As a teenager,she is reexposed to the measles virus during an outbreak at her high school.Explain the immune response that will most likely prevent Rebecca from experiencing any signs or symptoms of measles.

Question 42

Why is it important for T cells to weakly recognize self MHC proteins while strong recognition is problematic?

Question 43

A humoral immune response involves the production of ________.

Question 44

The small peptides released by various cells that influence the direction and intensity of an immune response are known as ________.

Question 45

One health risk associated with excessive cytokine release is the chance of

A) severe tissue damage.
B) cytokines destroying antibodies.
C) damage to virally infected cells.
D) inactivating mitosis.

Question 46

Describe the process of affinity maturation.

Question 47

A two-month-old baby is found to lack class I MHC molecules.How would this defect impact an adaptive immune response?

Question 48

Small molecules that do not elicit an immune response unless they are attached to immunogens are referred to as ________.

Question 49

Natalia and Julia are looking through primary literature for information about antibodies.One of the articles is titled "Generating Diversity in Idiotypes." Would you expect this article to compare different species,different individuals of the same species,or different antibodies within individuals? Explain your answer.

Question 50

Rank the following macromolecules in terms of their antigenicity and explain your ranking: carbohydrates,proteins,lipids,and nucleic acids.

Question 51

Bloodwork indicates that a patient who has pneumonia is actively secreting different forms of antibody against Streptococcus pneumoniae.Explain how the patient is able to respond to this pathogen by secreting more than one antibody.

Question 52

Describe the function of the major histocompatibility complex (MHC).

Question 53

Cells that become activated when they bind to intracellular antigen bound to class I MHC on antigen-presenting cells are known as ________ cells.

Question 54

Helper T cells display the surface antigen ________.

Question 55

Cytotoxic T cells display the surface antigen ________.

Question 56

CASE HISTORY
Nathan was a ten-month-old male who had suffered much in his short life.Since birth he had experienced recurrent serious extracellular bacterial infections,all of which were resolved by antibiotic treatment.On Christmas Day,Nathan's mother discovered he had another high fever and a nonproductive cough (no mucus).He was also having trouble breathing.Fearing one more serious infection,Nathan's mother rushed him to the hospital.An X-ray showed the lung infiltrate with the appearance of ground glass.A tube was placed through Nathan's nose and into his lung,and a solution was used to wash out deep-lung contents for microscopic examination (bronchoalveolar lavage).The fluid yielded microscopic organisms.Nathan was hospitalized with pneumonia caused by Pneumocystis jirovecii,a yeastlike fungus.Although most of us have been infected with this organism,our immune systems almost always prevent disease.Finding the disease in Nathan suggested a serious immune dysfunction.An immunological workup revealed mild neutropenia (lower than normal numbers of neutrophils)but normal numbers of T and B cells,normal levels of complement,and normal complement activity.However,Nathan's blood exhibited exceptionally high levels of IgM but very low IgG and IgA levels.The physician suspected a specific defect in Nathan's T cells.
Based on his findings regarding antibody production,which defect do you think Nathan's doctor suspects is causing Nathan's immunodeficiency?

A) a mutation affecting CD40
B) a mutation affecting CD8
C) a mutation affecting MHCI
D) a mutation affecting IL10

Question 57

Explain how humans are able to produce millions of different antibodies when there are only about 1,000 genes or gene segments involved in antibody formation.

Question 58

How do the structure and function of the F(ab)and Fc regions of an antibody differ?

Question 59

Immunoglobulin proteins are also known as ________.

Question 60

Proteins that do not require antigen processing and presentation are referred to as ________.

Question 61

Describe the two-step molecular process required to activate TH0 cells.

Question 62

CASE HISTORY
Nathan was a ten-month-old male who had suffered much in his short life.Since birth he had experienced recurrent serious extracellular bacterial infections,all of which were resolved by antibiotic treatment.On Christmas Day,Nathan's mother discovered he had another high fever and a nonproductive cough (no mucus).He was also having trouble breathing.Fearing one more serious infection,Nathan's mother rushed him to the hospital.An X-ray showed the lung infiltrate with the appearance of ground glass.A tube was placed through Nathan's nose and into his lung,and a solution was used to wash out deep-lung contents for microscopic examination (bronchoalveolar lavage).The fluid yielded microscopic organisms.Nathan was hospitalized with pneumonia caused by Pneumocystis jirovecii,a yeastlike fungus.Although most of us have been infected with this organism,our immune systems almost always prevent disease.Finding the disease in Nathan suggested a serious immune dysfunction.An immunological workup revealed mild neutropenia (lower than normal numbers of neutrophils)but normal numbers of T and B cells,normal levels of complement,and normal complement activity.However,Nathan's blood exhibited exceptionally high levels of IgM but very low IgG and IgA levels.The physician suspected a specific defect in Nathan's T cells.
Explain how a T-cell deficit could lead to this anomaly in antibody production,a task normally completed by B cells.Could this still be the source of the problem if the doctor had discovered that only IgA was high,rather than IgM?

Question 63

Explain the role of Class II MHC in B-cell activation.

Question 64

One way a pathogen may attempt to evade an immune response is by downregulating the production of Class I MHC molecules on infected cells.What type of pathogen would benefit from this adaptation and how would the pathogen benefit?

Question 65

CASE HISTORY
Luke,a 24-year-old mechanic from Egypt Beach,Massachusetts,was feeling run-down.Over the past month he had not been eating much and was always tired,and he recently noticed pain just under his right rib cage.His urine had recently turned the color of tea,and his wife noticed that the whites of his eyes were taking on a yellowish tinge.Luke finally went to the doctor,who suspected Luke had cirrhosis,a liver disease.This preliminary diagnosis was based on Luke's symptoms.Luke's abdominal pain was located over the liver,and the color of his urine and the jaundice evident in his eyes all pointed toward liver disease.Luke did not drink alcohol and had never left the country,but when questioned,Luke admitted to taking intravenous drugs.The doctor suspected hepatitis and ordered a series of blood tests to check for the presence of liver enzymes,antihepatitis antibodies,and hepatitis DNA or RNA in his blood.The tests revealed a high level of hepatitis B viral DNA.Luke had hepatitis B disease.
How can cellular immunity,which normally protects the body against known viral and other intracellular pathogens,be harmful to Luke,given his diagnosis? Consider how T cells recognize and respond to cells displaying foreign antigen.

Question 66

Describe how infection by a virus such as hepatitis B causes tissue damage.