Immunity and Vaccines
- Created by: Alice1425
- Created on: 09-05-19 14:44
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- Immunity and Vaccines
- Vaccines can protect individuals and populations against disease
- they contain antigens that cause your boy to produce memory cells against a pathogen without it causing disease
- you become immune without developing any symptoms
- Reduce the occurrence of a disease, therefore those not vaccinated are also less likely to catch it
- "Herd immunity"
- antigens may be free or attached to dead or attenuated pathogen
- can be injected
- can be taken orally
- could be broken down by enzymes in the gut
- vaccine molecules may be too large to be absorbed into the blood
- sometimes booster vaccines given to make sure memory cells are produced
- they contain antigens that cause your boy to produce memory cells against a pathogen without it causing disease
- Antigenic variability helps some pathogens evade the immune system
- Surface antigens activate primary response
- when infected a second time, same pathogen (with same antigen) activates secondary response so you don't get ill.
- Some pathogens change surface antigens
- "antigenic variation"
- formed due to changes in the genes of the pathogen
- memory cells do not recognise the new antigen
- immune system starts again and carries out primary response
- takes time, you get ill again
- immune system starts again and carries out primary response
- e.g HIV & Inflenza
- influenza vaccine changes ever year
- surface antigens change regularly, producing new strains
- Memory cells from one vaccination will not recognise new strains
- new vaccine is developed every year, government and health authorities implement a vaccination programme using the most suitable vaccine
- Memory cells from one vaccination will not recognise new strains
- surface antigens change regularly, producing new strains
- influenza vaccine changes ever year
- Makes it difficult to develop vaccines against some pathogens
- Surface antigens activate primary response
- immunity can be active or passive
- Active immunity
- takes a while for protection to develop
- type of immunity you get when your immune system makes its own antibodies after being stimulated by an antigen
- Natural
- becoming immune after catching a disease
- artificial
- Becoming immune after being vaccinated with a harmless dose of antigen
- Natural
- requires exposure to the antigen
- memory cells are produced
- Protection is long term because the antibody is produced in response to complementary antigen being present in the body
- Passive immunity
- the type of immunity you get from being given antibodies made by a different organism (your immune system doesn't make them on its own
- Natural
- when a baby becomes immune due to antibodies received from their mother (placenta and breast milk)
- Artificial
- when you become immune after being injected with antibodies from someone else
- e.g if you contract tetanus, you can be injected with antibodies against the tetanus toxin, collected from blood donations
- when you become immune after being injected with antibodies from someone else
- Natural
- doesn't require exposure to antigen
- protection is immediate
- memory cells not produced
- protection is short term because antibodies are broken down
- the type of immunity you get from being given antibodies made by a different organism (your immune system doesn't make them on its own
- Active immunity
- Vaccines can protect individuals and populations against disease
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