Recombinant Vaccines Question

Question 1

6 topics to discuss

Answer 1

Live attenuated
Recombinant subunit
Virus vector
DNA
Edible plant based
mRNA

Question 2

Live attenuated example

Answer 2

Polio

Question 3

Live attenuated

Answer 3

Weaker form of vaccine through multiple passaging at progressively lower temp
Administered mucosally typically
Mimic natural infection -> long lasting immunity

-reversion
- disease in immunocompromised host
- manufacturing and storage required stringent conditions

Question 4

Live attenuated RSV

Answer 4

Cold adapted temperature strategy
Could not find balance between immunogenicity and pathogenicity in infants. Alternative strategy was to remove virulence factors. Research ongoing

Question 5

Recombinant subunit vaccines example

Answer 5

Hep B and HPV

Question 6

Recombinant subunit vaccines development

Answer 6

Identify potential antigens

First in silico B and T cell epiptope candidate identification
Pep scan for T cell proliferation
ELISA for antibody reactivity

Question 7

Recombinant subunit advantages

Answer 7

High safety as do not contain live or inactivated virus
Well defined, highly purified
Targeted immune response against specific antigen

Question 8

How do we combat massive strain variation in HIV?

Answer 8

Recombinant vaccine derived from multiple strains or perhaps identify an antigen that confers subtypic immunity

Question 9

Recombinant vaccine disadvantages

Answer 9

May require adjuvants; very little choice of adjuvants; major research underway
Some viral antigens have complex structures that are challenging to produce recombinantly
Multiple doses may be required
Massive strain variation in HIV

Question 10

What happened this week?

Answer 10

AREXVY 🥳🥳🥳🥳
83% efficacy

Question 11

An example of a virus vector

Answer 11

SeV

Question 12

Virus vector

Answer 12

Engineered viruses that can deliver viral vaccines into host cells

Question 13

Advantages of virus vector vaccines

Answer 13

Efficient delivery and expression of viral antigen => mimicking natural infection
Induce cellular and humoral immune responses
Can target specific cells or tissues

Question 14

Disadvantages of virus vector vaccines

Answer 14

Pre existing immunity to vector may limit immune response
The immune response to the vector can limit subsequent vaccination
Vector production and purification is costly and time consuming

Question 15

DNA vaccines development

Answer 15

Direct introduction of plasmid DNA encoding viral vaccine antigens into host cells. Host cells produce viral antigen => immune response

Question 16

DNA vaccine advantages

Answer 16

Simplicity in design manufacture and storage
Still in development
Can induce both humoral and cellular immune response
Rapid development and scalability

Question 17

DNA vaccine disadvantages

Answer 17

May require delivery systems and or adjuvants
Further research into safety is needed

Question 18

Edible plant based vaccines development

Answer 18

Expression of viral antigens in GMO plants which can be consumed e.g tomatoes

Question 19

Edible vaccines advantages

Answer 19

Ease of production
Scalability
Cost-effective
Eliminate need for injections
Natural exposure and mucosal immunity

Question 20

Edible vaccine disadvantages

Answer 20

Regulatory hurdles and public perceptions on GMO
Achieving high antigen expression levels is difficult and hard to maintain their stability
More work needed on efficacy and safety

Question 21

mRNA development

Answer 21

SARS-CoV-2
25 years into mRNA vaccines, 10 years into SARS/MERS spike protein research
Utilises mRNA encoding viral vaccine antigen, taken up by host cells, transcribed and triggers immune response

Question 22

mRNA vaccine advantages

Answer 22

If sequence is known vaccine can be developed easily and efficiently
Strong immune response
92% efficacy

Question 23

mRNA vaccine disadvantages

Answer 23

Labile
Needs delivery package e.g lipids
Must be stored at extremely low temps