Viral vaccines I

Question 1

What is passive immunization?

Answer 1

Administration of antibodies to an unimmunized person from an immune subject to provide temporary protection against a microbial agent or toxin

Question 2

What kind of protection is provided by passive immunization?

Answer 2

Protection provided by antibodies created outside the body

Question 3

What is a well known example of passive immunization?

Answer 3

Diphtheria antitoxin (DAT)

Question 4

How is active immunity defined?

Answer 4

Immunity to a pathogen that occurs following exposure to this pathogen

Question 5

What are the functions of antibodies? (3)

Answer 5

1. Neutralization
2. Fc-receptor interaction -> ADCP and ADCC
3. Complement activation

Question 6

What are the two forms of passive immunization?

Answer 6

1. Natural
2. Artifical

Question 7

What is an example of natural passive immunization?

Answer 7

Maternal IgG transportation by the neonatal Fc receptor across the placenta

Question 8

How can we improve passive immunization in newborns before conception, during pregnancy and postnatal?

Answer 8

Before conception: MMR vaccine
During pregnancy: booster vaccines
Postnatal: breastfeeding

Question 9

What are examples of booster vaccines provided to the mother to improve passive immunization in newborns? (2)

Answer 9

1. Pertussis
2. RSV

Question 10

What is the best moment in pregnancy to administer a pertussis booster vaccine to the mother?

Answer 10

~22 weeks

Question 11

What kind of vaccines are generally avoided during pregnancy because of a theoretical risk to the fetus?

Answer 11

Live vaccines

Question 12

Which vaccines are associated with an adverse pregnancy outcome? How do you prevent this?

Answer 12

MMR vaccines –> vaccinate BEFORE conception

Question 13

What can be side effects of passive immunization? (3)

Answer 13

1. Allergic response
2. Serum sickness to proteins from non-human source
3. Local response

Question 14

What are examples of artificial passive immunization? (2)

Answer 14

1. Monoclonal antibodies
2. Polyclonal antibodies

Question 15

What are the characteristic features of monoclonal antibodies as means for passive immunization? (4)

Answer 15

1. Cheap
2. Mixed ab
3. Bind different areas of specific molecule
4. Tolerant of small changes in protein structures

Question 16

What are the characteristic features of polyclonal antibodies as means for passive immunization? (4)

Answer 16

1. Expensive
2. Single Ab species
3. Only bind single specific site
4. May recognize a particular protein form

Question 17

What are the indications to chose passive immunization? (2)

Answer 17

1. Insufficient antibody synthesis
2. Exposure to disease in case of absence of existing immunity and that disease is likely to cause disease

Question 18

Which types of antibody deficiencies exist? (2)

Answer 18

1. Inherited (primary) antibody deficiencies
2. Acquired (secondary) antibody deficiencies

Question 19

Name an example of an inherited antibody deficiency

Answer 19

XLA: X-linked agammaglobulinemia

Question 20

What are examples of how people acquire secondary antibody deficiencies? (2)

Answer 20

1. Chemotherapy
2. Immunosuppressive medication

Question 21

Name examples of viruses known to cause complications indicating the need for passive immunization? (2)

Answer 21

1. RSV
2. Rabies

Question 22

If someone is already vaccinated against rabies virus, what do you administer? How often?

Answer 22

Post-exposure vaccination (2x)

Question 23

If someone has not been vaccinated against rabies virus, what do you administer?

Answer 23

Vaccination 4x + HRIG (human-anti rabies immunoglobulins)

Question 24

What is the main challenge in treating non-vaccinated rabies patients in underdeveloped countries?

Answer 24

Immunoglobulins are not available –> you have to administer it very soon after

Question 25

What is meant with the vaccination paradox?

Answer 25

The ones you want to vaccinate most, are the hardest to protect

Question 26

What are the natural defenses against viruses? (3)

Answer 26

1. Barriers 2. Cells 3. Molecules

Question 27

What are the characteristics of the natural defenses? (3)

Answer 27

1. Fast 2. Aspecific 3. No memory formation

Question 28

Which cell types are involved in the innate natural defense? (3)

Answer 28

1. Granulocytes 2. Macrophages 3. NK cells

Question 29

Which molecules are involved in the innate natural defense? (3)

Answer 29

1. Interferon 2. Complement 3. Lysozymes

Question 30

Which two categories of vaccine formulation exist?

Answer 30

1. Classical 2. Novel

Question 31

What are examples of classical vaccine formulations? (3)

Answer 31

1. Live-attenuated vaccines 2. Inactivated vaccines 3. Subunit vaccines

Question 32

What are examples of novel vaccine formulations? (5)

Answer 32

1. DNA vaccines 2. Vector-based vaccines 3. Virus-like particles 4. Antigen-loading autologous cells (DC) 5. RNA vaccines

Question 33

Which technique is required for the development of novel vaccine formulations?

Answer 33

Recombinant DNA technology

Question 34

What are examples of viruses that are used for live-attenuated vaccines? (6)

Answer 34

1. MMR 2. VZV 3. Yellow fever 4. Influenza 5. TB 6. BCG

Question 35

What are the two groups of live-attenuated vaccines?

Answer 35

1. Virus that does not normally infect humans, but closely related to human virus 2. Take human pathogen and attenuate it -> then give it back

Question 36

What is an example of a human pathogen that has been attenuated before giving it back to humans? How was this achieved?

Answer 36

Mumps -> cultured in embryonic chicken eggs and cells

Question 37

What is an example of a virus that does not normally infect humans/cause disease, but does protect humans against a human variant of this virus?

Answer 37

Cowpox to protect against smallpox

Question 38

What are the advantages of live-attenuated vaccines (2)

Answer 38

1. Immune response resembles natural immunity 2. Long-lasting protection after single dose

Question 39

Live-attuenated vaccines: What is the benefit of in host replication of the pathogen?

Answer 39

Immune response resembles natural immunity (induction of CD4, CD8 and antibodies)

Question 40

What are the disadvantages of live-attuenated vaccines (3)

Answer 40

1. Safety risk in immunocompromised 2. Possibility to revert to wildtype 3. Interference by maternal antibodies

Question 41

What is the main benefit of an inactivated vaccine?

Answer 41

Eliminating infectivity without compromising immunogenicity

Question 42

Name some examples of viruses where inactivated vaccines are used (4)

Answer 42

1. Influenza 2. Polio 3. HAV 4. Bordetella pertussis

Question 43

How can you inactivate a virus to generate an inactivated vaccine? (3)

Answer 43

1. Chemicals (formalin) 2. Heat 3. Radiation

Question 44

What is a crucial requirement to induce an effective immune response using an inactivated vaccine?

Answer 44

Addition of adjuvant

Question 45

What is the main advantage of inactivated vaccines?

Answer 45

Safety

Question 46

What are the disadvantages of inactivated vaccines? (4)

Answer 46

1. Multiple dosages required 2. Short-lasting immunity 3. Poor CD8+ T cell response 4. Risk of priming for enhanced disease in certain viruses

Question 47

Inactivated vaccines may increase the risk of priming for enhanced disease. For which viruses is this the case? (2)

Answer 47

1. Paramyxoviruses 2. Feline coronavirus

Question 48

What are the two manufacturing options for subunit vaccines?

Answer 48

1. Non-recombinant 2. Recombinant

Question 49

What does non-recombinant manufacturing of subunit vaccines entail?

Answer 49

Fractionation of pathogen -> purify proteins

Question 50

What does recombinant manufacturing of subunit vaccines entail?

Answer 50

Express gene of interest in bacteria/yeast/cells -> purify proteins

Question 51

What are the most common antigens in subunit vaccines?

Answer 51

Capsid- or membrane proteins

Question 52

True or false: adjuvants are often required for induction of effective immune responses when using subunit vaccines

Answer 52

True

Question 53

What are the advantages of subunit vaccines? (3)

Answer 53

1. Safe 2. Selection of subunit -> targeted immune response 3. Marker vaccine possible

Question 54

What is the purpose of a marker vaccine?

Answer 54

In live stock: differentiating infected from vaccinated animals

Question 55

How can you use a subunit vaccine as a marker vaccine?

Answer 55

Discriminate animals that have been infected with a wildtype virus as opposed to animals that have been vaccinated

Question 56

How do you determine if live-stock is infected with a wild-type virus or the vaccine?

Answer 56

Screen entire herds with serology assay

Question 57

Why are the use of marker vaccines important for the live-stock sector?

Answer 57

If livestock becomes ill, you want to know if you have to kill your animals

Question 58

What are the disadvantages of a subunit vaccine? (3)

Answer 58

1. Poorly immunogenic -> multiple dosages 2. Short-lastig immunity 3. Poor induction of CD8 T cell response

Question 59

Why are subunit vaccines unable to induce a proper CD8+ T cell response?

Answer 59

No proteins endogenously produced

Question 60

Why are viral-like particle vaccines more potent?

Answer 60

Density of protein on the surface -> resembles wild type pathogen

Question 61

Name examples of VLP viruses (3)

Answer 61

1. HBV 2. HPV 3. HEV

Question 62

What are the advantages of VLP vaccines? (4)

Answer 62

1. Safe 2. Structural similarity with viruses 3. Selection of subunit -> targeted immune response 4. Marker vaccine possible

Question 63

What are the disadvantages of VLP vaccines? (4)

Answer 63

1. Poorly immunogenic -> multiple dosages 2. Short-lastig immunity 3. Poor induction of CD8 T cell response 4. Preexisting immunity to VLP vector

Question 64

What is an adjuvant?

Answer 64

Pharmacological/immunological agent that enhances the immune response to a vaccine

Question 65

What are the mechanisms by which an adjuvant can work? (4)

Answer 65

1. Antigen stabilization/delayed release 2. Enhanced uptake antigen macrophages 3. Activation co-stimulatory molecules 4. Improve delivery of antigens -> cytosol

Question 66

How is the effect of antigen stabilization/delayed release caused by adding adjuvants also called?

Answer 66

Depot effect

Question 67

How does activation of co-stimulatory molecules influence immunity? (2)

Answer 67

1. Influence innate immunity 2. Skew CD4 to Th2 response -> antibody production

Question 68

Name examples of adjuvants in virology (6)

Answer 68

1. Aluminium salts 2. Mineral oils 3. Bacterial products 4. Detergents 5. ISCOMs 6. Cytokines

Question 69

What is the working mechanism of DNA vaccines?

Answer 69

Genes that encode antigens of interest as bacterial plasmid DNA

Question 70

How is protein formation ensured by DNA vaccines? (3)

Answer 70

1. DNA taken up by host cells 2. Transient expression of encoded genes 3. Protein formation

Question 71

True or false: Immunogenicity of DNA vaccines is limited in humans, but works well in small laboratory animals

Answer 71

True

Question 72

What is the main challenge with DNA vaccines?

Answer 72

Administration

Question 73

Originally the 'gene gun' was used for administration of DNA vaccines. How does it work? (3)

Answer 73

1. Gold particles coated with DNA 2. Taken up by macrophages 3. Presentation to B- and T cells

Question 74

Which administration method is currently used for DNA vaccines?

Answer 74

Gas injections

Question 75

What are the advantages of DNA vaccines? (5)

Answer 75

1. Easy to produce 2. Induction humoral immune responses 3. Induction CD4/CD8 4. Very stable 5. Can encompass large inserts

Question 76

What are the disadvantages of DNA vaccines? (2)

Answer 76

1. Poorly protective 2. Perceived risk of genome integration