Vaccines and the immune system

Question 1

Immunisation

Answer 1

A long lived state of immunity against pathogens via memory cells

Question 2

The two types of immune system

Answer 2

Innate - non-specific, neutrophils etc

Adaptive: CD4+ and CD8+

Question 3

Attenuated vaccine

Answer 3

pathogen made less virulent by grown in sub-culture for long period and vaccine mutates so it is less dangerous but can revert back to infectious form (polio, yellow fever), +ve: stimulates memory cells, less virus needs to be injected, -ve: rarely virus reverts to virulent form and cause disease, can not be given to immunocompromised

Question 4

Inactivated/killed vaccine

Answer 4

virus grown in culture and treated with formaldehyde so can’t reproduce, +ve: low risk of infection, can be used on immunocompromised, -ve: can’t multiply so large number of virions to stimulate immunity, no memory, boosters needed, toxicity (pertussis)

Question 5

Inactivated toxin vaccine

Answer 5

very successful, can be plasmid or purified toxin which has been killed (tetanus and diptheria)

Question 6

recombinant subunit and adjuvant vaccine

Answer 6

antigens purified or produced by recombinant DNA technology - Hhep B antigen produced from gene transfected in yeast - yeast used as vector and incorporated into vaccine. Adjuvants (aluminium) cause slower release for more stimulation) and conjugate with protein to stimulate T cells - +ve: not infectious, -ve: antigens may not retain native form so Ig may not recognise

Question 7

Why must you use RNA vaccines with nanoparticles?

Answer 7

RNA is too fragile on its own

Question 8

What type of vaccine is MMR

Answer 8

Live attenuated

Question 9

What type of vaccine is DTP?

Answer 9

Toxoid

Question 10

AZ vaccine MoA

Answer 10

• AZ: adenovirus from chimpanzee used and spike protein from SARS-cov2 added
• Chimp adenovirus used because most of us have never come across before

Question 11

Moderna and Pfizer vaccines

Answer 11

• Moderna (modified RNA) and Pfizer
• Injecting pure RNA = higher change of recognition by TLRs and inflammation caused
• Injected → DC to LN → activate T cell, CD4 and CD8 cells
• Spike protein has two parts - S1 (receptor binding domain targeted by ABs) and S2
• S1 mutates to form different strains

Question 12

Allergy treatments

Answer 12

Oral DNA vaccines - DNA particles covered with chitosan to prevent digestion