Vaccines Flashcards
A vaccine is a
suspension of antigens that are intentionally put into the body to induce artificial active immunity
A specific immune response where
antibodies are released by plasma cells
There are two main types of vaccines:
Live attenuated
Inactivated
which mean
live attenuated mean weakened
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 immune system remembers the antigen when reencountered and produces antibodies to it, in what is a faster, stronger secondary response
Effectiveness of vaccines
Vaccines can be:
Highly effective with one vaccination giving a
Generally harmless as they do not cause
Highly effective with one vaccination giving a lifetime’s protection (although less effective ones will require booster / subsequent injections)
Generally harmless as they do not cause the disease they protect against because the pathogen is killed by the primary immune response
Unfortunately, there can be problems with vaccines
People can have a poor response (eg. they are malnourished and cannot produce the antibodies – proteins or their immune system may be defective)
Antigenic variation
antigenic concealment
Antigenic variation is what
the variation (due to major changes) in the antigens of pathogens causes the vaccines to not trigger an immune response or diseases caused by eukaryotes (eg. malaria) have too many antigens on their cell surface membranes making it difficult to produce vaccines that would prompt the immune system quickly enough
Antigenic concealment – this occurs when
the pathogen ‘hides’ from the immune system by living inside cells or when the pathogen coats their bodies in host proteins or by parasitising immune cells such as macrophages and T cells (eg. HIV) or by remaining in parts of the body that are difficult for vaccines to reach (eg. Vibrio cholerae – cholera, remains in the small intestine
