Types of Vaccines

Question 1

What is a vaccination?

Answer 1

Administration of a substance to induce an immune response
Typically a protein - aiming to induce antibody response

Question 2

Why do we vaccinate?

Answer 2

• To prevent infectious disease in an individual and/or their offspring and/or their population
• Disease eradication
• Therapeutic vaccines
• Immunocontraceptive vaccines - to control wildlife populations
• ASIT - Allergen-specific immunotherapy

Question 3

ASIT - Allergen-specific immunotherapy

Answer 3

Can immunise by administering small doses of allergen
Aims to redirect immune repose away from IgE dominated response

Question 4

What would make an ideal vaccine?

Answer 4

Safe
Cheap
Easy to administer
Stable for storage
Stimulates an immune repose that is:
○ Strong
○ Lifelong
○ Appropriate immune response
○ In the right place

Question 5

Types of Vaccines

Answer 5

Whole inactivated pathogen vaccine
Live attenuated vaccine
Recombinant DNA/Subunit vaccine
Virus Vectored vaccine
DNA vaccine
mRNA vaccine

Question 6

What is a whole inactivated pathogen vaccine?

Answer 6

○ Culture pathogen then inactivate with harsh chemicals
○ Can split pathogen open to expose proteins that are inside to immune response

Question 7

Pros and cons of Inactivated pathogen vaccines

Answer 7

+ Can be made rapidly
- If pathogen is dangerous - high level of containment required can be expensive
- Duration of immunity is shorter

Question 8

What is a live attenuated vaccine?

Answer 8

○ Take pathogen and multiply passage in a non-natural host in cell culture
○ Eventually results in attenuation
○ Will still replicate but without causing disease

Question 9

Pros and cons of live attenuated vaccine

Answer 9

+ Better at inducing immune response
- Potential for reversion to virulence
- Not good for immunocompromised individuals

Question 10

What is a subunit vaccine?

Answer 10

○ Take genes, clone and express in laboratory
○ Deleted gene for protein that causes disease
○ Can express individual genes in different cell types to create proteins that can be used to immunise animals

Question 11

Pros and Cons of subunit vaccines

Answer 11

+ Good for immunocompromised animals
- Poor immune response

Question 12

What is a virus vectored vaccine

Answer 12

Insert gene expressing proteins into different viruses

Question 13

Pros and cons of virus vectored vaccines

Answer 13

+ Replication involved so good immune reponse
- Only expressing one protein from target pathogen
- If you try to give booster doses immune response will wipe out vaccine by reacting to vector
- Might need different vaccine for priming and boosting

Question 14

What is a DNA vaccine?

Answer 14

○ Insert genetic material directly into animals
○ Proteins are sensitised in our cells
○ Require delivery via ‘gene gun’ into muscle cells

Question 15

Pros and Cons of DNA vaccines

Answer 15

+ Good T cell mediated immunity
- Difficult to get strong antibody response

Question 16

What is an mRNA vaccine?

Answer 16

○ mRNA encapsulated in protective layer of lipids to make a nanoparticle
○ Translation of mRNA into protein in the cell

Question 17

Pros and Cons of mRNA vaccines

Answer 17

+ Good immune reponse
- Need to maintain cold chain - mRNA is fragile

Question 18

Components of a vaccine

Answer 18

• Active ingredients
• Stabilisers
• Preservatives
• Trace components
• Adjuvants

Question 19

What is an adjuvant?

Answer 19

Non-antigen component
Enhances immunogenicity (particularly with killed and subunit vaccines)
Original adjuvant was aluminium salt (alum)
Helps ensure vaccine isn’t immediately swept away
○ Induces cytokine and chemokine messengers to stimulate immune response