Vaccination Flashcards
What is herd immunity?
The indirect protection from infection of susceptible members of a population, and the protection of the population as a whole, which is brought about by immune individuals
- high numbers of the population need to be vaccinated for this to be effective
What is passive immunity and when is it used?
- Provides rapid protection by administration of specific antibodies
- Often used in cases of accidental exposure of susceptible animals to pathogens
- Used as supportive therapy in animals with compromised immune systems
e. g. colostrum in newborns
What are the 2 preferred responses to vaccination?
- Stimulation of long-term memory
- Rapid secondary response
What type of cells are killed by Cytotoxic T lymphocytes?
- virus infected cells
- cancer cells
- cells containing intracellular bacteria
- do not kill free virus
What kills free virus?
Virus neutralising antibody
Why are subcutaneous vaccines so useful?
- Skin contains specialised monocyte-derived epidermal cells = Langerhans cells
- Precursors of dendritic cells
- Capture and process antigens in skin
- Travel in lymph to lymph node
- Become follicular dendritic cells
- Stimulate T-cells very effectively
What is an adjuvant?
Non-specific enhancers of immune responses to non-living vaccines
How do adjuvants function?
- Enabling slow release of vaccine antigens into the body to enhance immune recognition and response
- Stimulating the immune system non-specifically
Give 3 examples of adjuvants
- Aluminium and calcium salts
- Microbial products
- Synthetic agents
- Exogenous cytokines
What are the pros and cons of using dead vaccines?
- Safer than live vaccines
- Give better antibody responses compared to CMI
- Less immunogenic
- Have to be administered more often
- Not effective by natural infection route
- Need adjuvants for effective immunity
What are live attenuated vaccine antigens?
- mutants selected in vitro to reduce virulence but retain antigenicity
- Live “vectors” into which are inserted specific gene products