Deck 17: Infectious Diseases and Vaccines

Question 1

Viruses, like many good pathogens, have adapted to survive in their hosts.Which of the following scenarios would be MOST favorable to viral transmission and long-term survival of the viral species?

A)Virus X enters a host cell, produces many progeny viruses (virions), and lyses the host cell.
B)Virus X enters the host cell and merges viral DNA with the host DNA so that the virus is copied into all progeny host cells.
C)Virus X enters the host cells, merges viral DNA with the host DNA until the host cell is stressed, and then begins to produce many virions eventually lysing the host cell.
D)Virus X enters the host cell and consistently makes virions at a low level so that all host cell functions are not disrupted.
E)Virus X enters the host cell, makes many progeny virions, and releases virions through exocytosis so that each virion is wrapped in the host cell plasma membrane.The host cell will eventually die or be targeted by the immune system for apoptosis.

Answer 1

D

Question 2

Which of the following is NOT important for controlling infections at either barrier or mucosal sites?

A)T_H2 CD4⁺ T cells
B)IL-4
C)IgA
D)IgG
E)IgE

Answer 2

D

Question 3

Which of the following is recognized by the innate immune system and triggers an immune response that will produce antiviral cytokines and trigger effector molecules?

A)Complement
B)IgA
C)IL-2
D)PAMPs
E)TNF- ?

Answer 3

PAMPs

Question 4

One mechanism that viruses use to avoid the immune response is to bind up immune effector molecules.All of the following methods are used by antibodies to block viral infection EXCEPT

A)antibodies bind to and coat virus particles, preventing viral ligands from binding to cell receptors.
B)antibodies trigger complement, which can lyse viral particles or recruit opsonins.
C)antibodies stimulate activation of cytotoxic T cells.
D)antibodies aid in phagocytosis.
E)antibodies compete for binding with viral ligands.

Question 5

Viruses such as Epstein-Barr virus, cytomegalovirus, and HIV are capable of suppressing the immune system by

A)binding antibodies but avoiding an immune response.
B)infecting lymphocytes or phagocytic cells.
C)production of cytokine antagonists.
D)wrapping progeny viral particles in the host-cell plasma membrane.
E)both infecting lymphocytes or phagocytic cells and production of cytokine antagonists.

Question 6

By which mechanisms can bacterial pathogens evade a host immune response?

A)Avoiding phagocytosis by the production of a capsule.
B)Escape of the phagolysosome within phagocytic cells.
C)Neutralization of digestive enzymes found within phagocytic cells.
D)All of the answers are correct.
E)None of the answers are correct.

Question 7

Which pathogen would be LEAST affected by a host complement attack?

A)Rotavirus (nonenveloped virus)
B)Influenza (enveloped virus)
C)HIV (enveloped virus)
D)Gram-negative bacteria
E)Gram-positive bacteria

Question 8

Each of the following is a step in bacterial infection EXCEPT

A)attachment to host cells.
B)the host feels tired or uncomfortable.
C)invasion of host tissue.
D)proliferation of bacterial cells.
E)toxin-induced damage to host cells.

Question 9

_____ is/are known as an endotoxin.

A)C3a
B)Capsular proteins
C)Flagellar proteins (H antigen)
D)Lipid A of the LPS in gram-negative cells
E)Peptidoglycan in gram-positive cells

Question 10

Anaphylatoxins stimulate a localized inflammatory response, which includes mast-cell degranulation, vasodilation, and recruitment of lymphocytes and phagocytic cells.What is the purpose of this localized immune response?

A)Mast cells contain histamine, which triggers vasodilation, which will increase blood flow to an infected area so that higher numbers of white blood cells will be recruited.
B)Serum proteins contain specific and nonspecific immune effector molecules to bind up and neutralize the invading pathogen and any toxins.
C)Vasodilation locally increases the temperate of an infected area so that bacterial proteins become denatured.
D)Vasodilation increases tenderness at the site of infection and causes edema (swelling) to that the host is careful not to overuse or tax the infected area.
E)All of the answers are correct.

Question 11

Which of the following are anaphylatoxins?

A)C1 and MASP-1
B)C3a and C5a
C)C3b and C5b
D)C4b and factor D
E)C5b and the MAC

Question 12

Parasitic infections include

A)protozoans.
B)protozoans and helminthes.
C)prions and viruses.
D)prions, viruses, and bacteria.
E)protozoans, helminthes, prions, viruses, and bacteria.

Question 13

Sleeping sickness and Chagas's disease are caused by members of the genus Trypanosoma, protozoans that reside in the bloodstream.What is the principle way trypanosomes evade the immune response?

A)Antagonistic cytokines are produced by the trypanosome.
B)Periodic changes in the surface antigen (VSG) of trypanosomes ensures that at least some cells will survive antibody mediated attacks.
C)Trypanosomes are human pathogens and thus immune to human immune responses.
D)Trypanosomes invade the brain and red blood cells so that immune effector cells such as macrophages and dendritic cells cannot phagocytize trypanosomes.
E)Vaccines are readily available to people in trypanosome infested areas.

Question 14

How do Plasmodium cells avoid immune clearance?

A)Antagonistic cytokines are produced by the Plasmodium cells.
B)Periodic changes in the surface antigen (VSG) of Plasmodium ensures that at least some cells will survive antibody mediated attacks.
C)Plasmodium cells show multidrug resistance.
D)Plasmodium invades red blood cells so that immune-effector cells such as macrophages and dendritic cells cannot phagocytize Plasmodium cells.
E)TNF- ? is produced in large amounts by Plasmodium, thus overwhelming the immune response and creating a cytokine storm.

Question 15

Schistosomiasis is a debilitating and potentially fatal disease caused by the helminthic parasite Schistosoma.Which antibody is specific for helminth response?

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

Question 16

Leishmaniosis is a disease that can either be fatal to its host or will be cleared by the immune response of the host.Which pathway is responsible for clearing leishmaniosis?

A)Memory B cells
B)Complement
C)Plasma cells
D)T_C cells
E)T_H cells

Question 17

Some species of fungi are part of the normal microbiota or normal microbial flora of a host organism.How does the immune system differentiate between "good" fungi and "bad" fungi?

A)Good fungi only reside in certain places and thereby will not trigger an immune response.
B)Good fungi are weakly virulent, whereas bad fungi are highly virulent.
C)Fungi are differentiated based on their cytokine production.
D)Low levels of any fungi are ignored by the immune system.
E)PAMPs such as motifs in peptidoglycan are used to mark fungal cells.

Question 18

Cryptococcus may spread throughout an infected host.By what mechanism is Cryptococcus controlled by the acquired immune system?

A)Activation of T_H cells
B)Degranulation of eosinophils and IgE
C)Expression of TNF- ?
D)Granuloma formation
E)Plasma cell activation

Question 19

Primary virulence in fungi indicates

A)an aggressive fungal infection.
B)infection in a healthy person by a fungal species with high pathogenicity.
C)infection by an opportunistic fungal species with low pathogenicity.
D)infection by a multidrug-resistant fungal species.
E)infection by multiple fungal species at once.

Question 20

People encounter fungi on a daily basis, yet few healthy individuals develop fungal infections.Each of the following are mechanisms of the innate immune system that help prevent or limit fungal infections in healthy individuals EXCEPT

A)neutrophils are especially good at phagocytizing fungal cells.
B)normal microbial flora (commensals) limit fungal growth by toxin (antimicrobial) production.
C)normal microbial flora use available nutrients and colonization space on the host, which makes the host an inhospitable environment for fungal cells.
D)PAMPs such as b-glucans, mannans, and chitin are recognized by innate immune cells.
E)several species of fungi are able to block PRR binding.

Question 21

Acquired fungal immunity is supported by

A)multiple antifungals and vaccines that are available.
B)normal flora species that produce new antimicrobial compounds.
C)plasma-cell and memory B-cell activation.
D)T_H1 and IFN- ? production.
E)TNF- ? and T_C production.

Question 22

Which type of pathogen mutates at the HIGHEST rate?

A)HIV
B)Influenza
C)E.coli
D)Plasmodium falciparume.
E)Candida sp.

Question 23

Which of the following is NOT considered to be a newly emerging infectious disease?

A)Ebola
B)Legionnaires disease (Legionella)
C)Multidrug-resistant tuberculosis
D)SARS
E)West Nile

Question 24

Re-emerging infectious diseases present a major problem worldwide.What actions can be taken to prevent the spread of re-emerging infectious diseases such as whooping cough (Bordetella pertussis)?

A)Create new antibiotics, antifungals, and antivirals to treat existing strains of pathogen and limit development of multidrug resistances.
B)Ensure proper precautions during travel, especially for airborne pathogens.
C)Maintain rigorous vaccination programs for all healthy individuals.
D)Provide herd immunity during outbreaks.
E)All of the answers are good preventive actions.

Question 25

Vaccines are MOST readily made against

A)bacteria, because their cell walls remain relatively unchanged from generation to generation.
B)fungi, because several species of fungi are commensals, therefore priming the immune response to readily produce antibodies to the new vaccine.
C)helminths, because they are large organisms and make for easy targets.
D)prions, because they are new microbe so there is much research effort to stop prion-related diseases.
E)viruses, particularly RNA viruses, because their cell receptors are unchanging and bind human cell receptors.

Question 26

Modern-day vaccines try to elicit an immune response from

A)memory B cells.
B)cytotoxic T cells.
C)hematopoietic stem cells.
D)innate immune cells.
E)naïve B cells and T_H cells.

Question 27

Which of the following is an example of a passive immunization?

A)Antibodies against rabies given to someone who was bitten by a potentially rabid dog.
B)Heat-killed flu antigen grown in chicken eggs.
C)Live viral antigen given on a sugar cube to protect against polio.
D)All of the answers are correct.
E)None of the answers are correct.

Question 28

Which maternal antigens are protective against diseases such as diphtheria, tetanus, streptococcal infections, and measles?

A)IgA and IgE
B)IgA and IgG
C)IgD and IgE
D)IgG and IgM
E)All classes of immunoglobulins.

Question 29

Why does active immunity produce long-term immunity better than passive immunity?

A)Active immunity always leads to having the illness though in a milder form than an unvaccinated individual.
B)Antibodies do not produce long-term immunity because they break down after two weeks.
C)During active immunity, antigens for the disease are presented to the immune system through classical antigen presentation mechanisms, so an active B-cell response and immunologic memory develop.
D)Long-term storage of antibodies maintains vaccine integrity; however, antigens cannot be stored long term.
E)All of the answers are correct.

Question 30

Several vaccines are combination vaccines and are used to vaccinate people against two or more pathogens.One example of a combination vaccine is the TDaP vaccine (tetanus, diphtheria, and pertussis).How does a combination vaccine develop immunologic memory to more than one pathogen?

A)Allergic reactions are less common with combination vaccines than with single-antigen vaccines.
B)Combination vaccines develop immunity against very similar or the same (broad spectrum) antigens.
C)Combination vaccines are more economical to produce than single vaccines.
D)Each antigen target included in the combination vaccine must be different enough so that the immune system can recognize the target antigen on the pathogen cell.
E)Similar antigens can be chemically modified so that the immune system will recognize each antigen as unique.

Question 31

What would happen if a person who is undergoing chemotherapy were given a live virus vaccine against polio?

A)The cancer patient would likely develop a strong immune response to the vaccine because a live viral antigen was used.
B)The cancer patient would likely develop polio because the immune system is compromised and would not be able to fight off the live virus.
C)The chemotherapy the cancer patient is receiving would inactivate the vaccine by killing the live polio virus.
D)There would be no effect, as the cancer patient does not produce a high number of immune cells for the polio virus to interact with.
E)Using a live viral antigen in a vaccine is lethal to immunocompromised people because their immune system would be overwhelmed and toxic shock would occur.

Question 32

What is herd immunity?

A)A global vaccination day established by the World Health Organization to ensure every person on the planet is vaccinated against a particular pathogen.The last herd immunity day was in the early 1980s with smallpox.
B)A vaccination program started by progressive nations to prevent the spread of prion diseases such as Mad Cow (BSE).
C)Herd immunity refers to a special vaccination method whereby immunocompromised individuals are given vaccines made only of antibodies.
D)Receiving all government recommended vaccines in one day.This produces the strongest immune response possible but frequently leaves the person being vaccinated experiencing malaise (generally feeling bad) and feeling feverish.
E)Vaccinating the majority of a population to protect immunocompromised individuals from a particular pathogen.

Question 33

Which infectious disease is the BEST example of "original antigenic sin?"

A)HIV
B)Influenza
C)Measles
D)Tapeworms
E)Toxoplasma

Question 34

What type of vaccine would be MOST effective against tuberculosis, a disease that requires a strong CD4⁺ T-cell response?

A)Toxoid
B)DNA
C)Subunit
D)Inactivated
E)Live attenuated

Question 35

Physical barriers are an important (and often effective) defense against various types of potential invaders.Summarize one method by which many different pathogens have evolved to use other organisms to bypass this layer of protection.

Question 36

What are two different types of infections that can be cleared using IgA? Explain their functions.

Question 37

What are three different ways viral and bacterial pathogens can evade our immune systems? Provide species-specific examples in your response.

Question 38

What are three ways in which Plasmodium, the causative agent of malaria, is able to overcome our immune systems and medical treatment? Explain.

Question 39

You are analyzing the immune response of an ill patient.The patient's serum contains low levels of IgG and interferon molecules but is dominated by IgE antibodies and the production of the cytokine IL-4.What type of infection is MOST closely associated with this immune response? Explain.

Question 40

Why is developing an effective response to trypanosome infection challenging for our immune system?

Question 41

Define "emerging disease," and provide an example of one.

Question 42

In what situation is a toxoid vaccine an effective strategy? What special care has to be taken when preparing them? Explain.

Question 43

List the major types of vaccines.Which is the strongest? The weakest? Explain why it is often necessary to develop weaker vaccines.

Question 44

In efforts to cut funding for basic research, lobbyists and politicians will often frame said research as being wasteful, or without purpose.You are studying a harmless virus that exclusively affects bats.Using an example from the text, pose a counter argument defending the importance of your research.