Vaccinations

Question 1

What may a vaccine be made of?

Answer 1

inactivated protein
recombinant protein
Live attenuated pathogen
Dead pathogen
Carbohydrate

• stablising buffers, adjuvants, alum, water

Question 2

What are the characteristics of Recombinant protein vaccines?

Answer 2

Hep B surface antigen example

Induces classic neutralising antibodies

+ Pure, safe

• expensiveish, not very immunogenic

Question 3

What are the characteristics of Toxoid Vaccine?

Answer 3

E.g. Tetnus - inactive toxin

Induces antibody, blocks toxin

+ cheap, safe, long used

• need to understand the biology,
• not all organisms use toxin

Question 4

What are the characteristics of bacterial polysaccharides?

Answer 4

Capsule

Will not create strong B cell response

• for an alternate option : Conjugate vaccines

Question 5

What are the characteristics of Conjugate vaccines?

Answer 5

Polysaccharide coat componant coupled with immunogenic carrier protein

Protein enlists CD4 help to boost B cell response to the polysaccharide

+ improves immunogenicity
+ highly effective at controlling bacterial infection

• cost
• carrier protein interference
• very strain specific

Question 6

Describe the mechanics of conjugate vaccines?

Answer 6

Protein with polysaccaride seen by DC and B cell

DC takes up the vaccine whle and presents the protein
B cell creates an antigen for the polysaccaride and presents it

Presenting DC Is seen by T follicular helper cell which binds to it then goes and binds to the antigen on the B cell to boost the activity

The B cell develops plasma cells which will release anitibodies against the sugar

Question 7

What are Adjuvants?

Answer 7

Substances used in combination with a specific antigen to produce a more robust response

Induce danger signals to activate DC cells so they present antigens to T cell

examples : Alum, Vaccine for Chicken pox, ASO3 GSK adjuvant

Question 8

What are the characteristics of Live attenuated vaccines?

Answer 8

E.g. BCG, LAIV, OPV

pathogens lose virulence

Replicate in situ they trigger a innate response

+ induce strong response

• Can revert back to virulence when out of body through urine eg. sewerege –> environment
• Can infect the immunocompromised
• Attenuation may lose key antigens
• Can be competed out by other infections

Question 9

What are the characteristics of dead pathogen vaccines?

Answer 9

E.g. Influenza

Chemically killed pathogen

Induces antibody and T cell response

+ leaves antigenic componants
+ cheap, quick

• Fixing/killing can alter chemical structure of antigen
• Requires capacity to grow the pathogen