Vaccination Flashcards
Define ‘herd immunity’
indirect protection from infection of susceptible members of a population + protection as a whole brought about by the presence of immune individuals
What is passive immunity?
Administration of specific Abs that gives rapid protection
When is passive immunisation given to animals?
failure to receive maternal Abs through colostrum, acute risk of acquiring infectious disease, as supportive therapy for those w/ compromised immune system
Describe + explain how the subcutaneous route of immunisation works?
Skin contains specialised, monocyte- derived epidermal cells (Langerhans), precursors of dendritic cells, capture + process Ags in skin and travel in lymph to lymph node to become follicular dendritic cells = stimulate T cells
Name methods of mucosal administration
- oral
- intranasal
- aerosolised vaccines
- vaccines mixed in feeds
What are adjuvants?
non-specific enhancers of immune responses to non-living vaccines
How do adjuvants function?
- enable slow release of vaccine Ags into the body to enhance immune recognition + response
- stimulation of immune system non-specifically
Name some examples of adjuvants
- Al + Ca salts
- microbial products (e.g. bacterial cell wall fragments)
- Synthetic agents
- Exogenous cytokines
What types of vaccine are there?
Live attenuated, inactivated, subunit, toxoid
What are the pros of living vaccines compared to inactivated vaccines?
- few inoculating doses required
- adjuvants unnecessary
- less chance of hypersensitivity
- relatively cheap
What are the pros of inactivated vaccines compared to living vaccines?
- stable on storage
- unlikely to cause disease through residual virulence
- unlikely to contain contaminating organisms
What are the pros + cons of dead vaccines?
- safer than live
- less immunogenic
- gives better Ab responses compared to CMI
- Need adjuvants
- Needs to administered more often
- Not effective by natural infection route
What are subunit vaccines?
contain fragments of native / recombinant antigens
How are live attenuated vaccines made?
mutants selected in vitro to reduce virulence but retain antigenicity, mutants identified + selected from natural strains, live ‘vectors’ into which are inserted specific gene products
How do anti-toxin vaccines differ from other vaccines?
Don’t protect against infection but against toxin produced by pathogen
