Immunity and Vaccines Flashcards
What happens to your body without a vaccine?
Whilst B-cells are dividing to produce enough antibodies to deal with the pathogen, you suffer from symptoms of the disease
What do vaccines contain?
Vaccines contain antigens that cause your body to produce memory cells against a particular pathogen, without the pathogen causing disease
What is herd immunity?
Vaccines protect individuals that have them, because they reduce the occurrence of the disease, without the pathogen causing disease. Those not vaccinated are also less likely to catch the disease because there are fewer people to catch it from
What state are the antigens in, in the vaccine?
The antigens may be free or detached to a dead or attenuated pathogen
How can vaccines be taken?
Vaccines can be taken orally or injected
What is the disadvantage to taking vaccines orally?
The vaccine could be broken down by enzymes in the gut or the molecules of the vaccine may be too large to be absorbed into the blood
Why are booster vaccines given?
Booster vaccines are given to make sure that memory cells are produced
Antigens on the surface of pathogens activate what?
The primary response. When you’re infected a second time by the same pathogen they activate the secondary response
What is antigenic variation?
Some pathogens are able to change their surface antigens - these changes are due to changes in the genes of the pathogen. This antigen variability is called antigenic variation
How does antigenic variation affect the secondary response?
Antigenic variation means that when you’re infected a second time, the memory cells produced from the first infection will not recognise the different antigens. So the immune system has to carry out a primary response against the new antigens
Antigenic variation makes it difficult to develop what?
Vaccines
How does antigenic variation affect the production of vaccines against influenza?
- The influenza vaccine changes every year because the antigens on the surface of the influenza virus change regularly, forming new strains of the virus
- Memory cells produced from vaccination with one strain will not recognise other strains with different antigens. The strains are immunologically distant
- Every year there are different strains of the influenza virus circulating in the population, so a different vaccine has to be made
- New vaccines are developed and one is chosen every year that is the most effective against the recently circulating influenza viruses
- Governments and health authorities implement a programme of vaccination using the most suitable vaccine
Give the two types of immunity
- Active immunity
2. Passive immunity
What is active immunity?
This is the type of immunity you get when your own immune system makes its own antibodies after being stimulated by an antigen
What are the two types of active immunity?
- Natural - when you become immune after catching the disease
- Artificial - when you become immune after you’ve been given vaccination containing a harmless dose of the antigen