Scientific basis of vaccines Flashcards
What is herd immunity memory boosted by?
Periodic outbreaks of disease in community and vaccines
What do parenteral vaccines lead to?
Poor mucosal immunity
What does monotypic mean?
Surface antigens remaining the same generally so vaccination (or infection) gives lifelong immunity
What does polytypic mean?
Surface antigens change and immunity is readily overcome
What are the types of vaccine?
Live, attenuated
- MMR
- yellow fever
Killed whole organism
- influenza
- polio
- HepA
Subunit
Describe live vaccines
Attenuated by:
- Culture it in a foreign host many times (add mutations)
- Chemically cause mutations to attenuate it
- Genetically engineer to create knockouts lacking genes for virulence
Issues:
- Vaccine may mutate back to original form
- Generally needs to be kept cold
Positives:
- Useful for producing CTL memory cells because they can infect APCs
What are the issues with killed whole organism vaccines?
Need boosting to get good protection
Heat or chemicals to kill them
What are the individual components of bacteria that are used in subunit vaccines?
Proteins
Toxoids
Peptides
Polysaccharide
What are bacterial toxins inactivated with for use in vaccines?
Formaldehyde
What are the features of bacterial capsular polysaccharides as vaccines?
Poor antigens
Short term memory
No T cell immunity
How does enhancing immunogenicity work?
If you just use the polysaccharide theres only an antibody response
If you conjugate it to another cell then T cell binding occurs
What are vaccine adjuvants?
Things you add to vaccines to make them more immunogenic
- Enhance immune response to antigen
- Promote uptake and antigen presentation
- Stimulate correct cytokine profiles
Where do you get passive immunity from?
Maternal transfer or serum from another source
