Antiviral agents, vaccines and adjuvants

Question 1

What do antiviral drugs target?

Answer 1

The replication step that is unique to viruses

Many of their replication steps are similar to mammalian host’s

Question 2

What are the viruses that there are common antivirals used?

Answer 2

HIV
influenza
Hepatitis (B and C)
herpesvirus

Question 3

What steps in replication do most aniviral drugs target?

Answer 3

1. attachment to and penetration of the host cell
2. uncoating
3. synthesis of viral components
4. virus assembly
5. virus release

Question 4

What are two major drug groups that interfere with replication of viral genome?

Answer 4

1. nucleoside

2. non-nucleoside inhibitors

Question 5

What are nucleosides?

Answer 5

They have a similar structure to nucleotides –> block DNA replication and inactivate enzymes

Question 6

What are non-nucleoside inhibitors?

Answer 6

Inhibit reverse transcriptase by binding virus’s active site on the cell

Question 7

What are 4 major ways antivirals can interfere with synthesis and viral components?

Answer 7

1. Inhibition of replication (blocs nucleotide placement or interferes with reverse transcriptase)
2. Prevent transcription and translation
3. Inhibit viral enzymes needed for virus replication
4. prevent posttransitional processing

Question 8

What three components of the host immune system will protect them from infection?

Answer 8

1. Use of interferons or cytokines
2. Enhancement of innate immunity
3. use of specific antibodies (part of passive immunization)

Question 9

What are the two major types of immunization?

Answer 9

1. Passive immunization

2. Active immunization

Question 10

What is passive immunization?

Answer 10

Transfer of Ab to nonimmune animal (maternal or artificial)

Question 11

What is active immunization?

Answer 11

specific aquired immunity from immunization with virus or viral antigens

Question 12

What type of immunization does a vaccine provide?

Answer 12

Active immunization

Question 13

What are the 6 conventional vaccines?

Answer 13

1. Attenuated (live)
2. Inactivated (killed)
3. Subunit
4. VLP (virus like particles)
5. DNA vaccine
6. Vectored

Question 14

What are attenuated vaccines?

Answer 14

Live virus vaccine containing weakened form of the organism

- altered to lose pathogenicity for its host but retain immunogenicity

Question 15

What are inactivate vaccines?

Answer 15

Killed
inactivating pathogenic agent (block its replication) –> immunogenic antigen is inoculated into immunocompetent host w/o causing infection

Question 16

What are subunit vaccines?

Answer 16

One or more immunogenic components (purified or recombinant antigens) of a pathogenic organism

Question 17

What different types of subunit vaccines exist?

Answer 17

1. Naturally occuring – use more benign virus to inoculate against virulent virus (cowpox for smallpox)
2. Recombinant protein - protein confers protection is identified and gene is closed in expression vector –> expressed in different cell systems for reproduction and vaccine production
3. Immunologic peptide – immunogenic epitopes chemically sysnthesized
4. Anti-idiotypic antibodies - Ab targeting Ag binding site of another Ab

Question 18

What is a VLP vaccine?

Answer 18

noninfectious macromolecule

self-assembly of viral structural proteins devoid of viral genetic material

Question 19

What is a DNA vaccine?

Answer 19

Plasmid DNA introduced to host cell –> taken up –> gene of interest is expressed –> cell expresses foreign antigen –> host immune system recognizes it –> humoral + cell mediated immune response

Question 20

What are vectored vaccines?

Answer 20

using non-pathogenic viruses or bacteria to deliver foreign genes into host

Question 21

What is an adjunct?

Answer 21

materials mixed with vaccine to potentiate the immune response.

Question 22

What is the MOA of adjuncts?

Answer 22

1. prolonged retention and slow release of antigen
2. activation of macrophages –> lymphokines
3. Mitogenicity for lymphocytes

Question 23

What are the 6 adjuvants used in animal vaccines?

Answer 23

1. Alum
2. Mineral oils
3. Muramyl dipeptide (new)
4. Liposomes
5. Immunostimulating complexes (ISCOM)
6. Alginate microspheres

Question 24

What type of vaccine has high amount of virus in the dose?

Answer 24

Inactivated

Question 25

What is the route of administration for attenuated and inactivated vaccines?

Answer 25

Attenuated: injection, inhalation, or oral
Inactivated: injection

Question 26

T/F

You need to give multiple doses of inactivated vaccines

Answer 26

True

Question 27

Which has longer duration of immunity, attenuated or inactivated vaccine?

Answer 27

Attenuated (many years)

DNA vaccines too!

Question 28

What are some things to think about that may compromise safety of vaccines?

Answer 28

Contaminating viruses
Underattenuation
Genetic instability
Heat lability 
Adverse effects in pregnant animals
Adverse effects from inactivating vaccines

Question 29

What is herd immunity?

Answer 29

When the protection of unvaccinated animals is held through a certain threshold number of individuals getting vaccinated

Question 30

What are 4 mucosal surfaces we can deliver vaccines? Why is this a good idea?

Answer 30

1. Intranasal
2. Rectally
3. Intratrachea
4. Oral
   This provides good access to local lymph nodes that provide adequate Ab response