Vaccines
- A vaccine is a source of antigens or DNA/RNA which codes for antigens
- The vaccine is introduced into the body to induce immunity without causing the disease
- Vaccines cause a specific immune response where antibodies are released by plasma cells
- There are different types of vaccine, including
- Live attenuated - these are weakened versions of the pathogen
- Inactivated - these are killed, non-living components of pathogens or even just the antigens alone
- Vaccines are administered either by injection or orally (by mouth)
- The vaccinations given by injection can be into a vein or muscle
- Vaccinations produce long-term immunity as they cause memory cells to be created
- The memory cells recognise the antigen when re-encountered and produces antibodies, in what is a faster, stronger, secondary response
Vaccination & antibodies graph
Examiner Tip
Remember vaccines trigger the primary immune response (T helper cells trigger B plasma cells to secrete specific antibodies) which leads to the production of memory cells which will give a faster and larger (higher concentration of antibodies) secondary response.