2C-cells and immune system-immunity and vaccines Flashcards
what is an active immunity
when your immune system makes its own antibodies after being stimulated by an antigen
what are the two different types of active immunity
natural- when you become immune after catching the disease
artificial- become immune after been given a vaccination
what is passive immunity
when you are given antibodies made by a different organism
two types of passive immunity
natural- when baby becomes immune due to the antibodies it receives form its mom
artificial- when you become immune after being injected with antibodies from someone else
difference between active and passive immunity
active- requires exposure to antigen
passive- doesn’t require exposure to antigen
active- it takes while for protection to develop
passive- protection is immediate
active- memory cells produced
passive- memory cells aren’t produced
active- protection long term because the antibody is produced
passive- protection short term because the antibodies given are broken down
what do vaccines do
contain antigens that cause the body to produce memory cells against pathogen without pathogen causing disease. so become immune without symptoms
what is herd immunity
vaccines reduce occurrence of the disease so those not vaccinated are less likely to catch the disease
why are oral vaccines bad
because enzymes might be broken down in the gut
ethical problems with vaccines
testing vaccines on humans can be risky. some people don’t take it because of the side effects if there was an epidemic there would be a rush to receive the new vaccine which would be difficult on who would receive it first
what is antigenic variation
antigens on the surface of pathogens activate the primary response. when infected a second time the secondary response is activated so you don’t get ill. but some pathogens change their antigens on their surface
what is the problem with antigenic response
when your infected the second time the memory cells produce the first time don’t recognise the different antigens so the immune system starts again from primary response so you get ill again
how does antigenic variation make it difficult to develop a vaccine
antigens on the surface of the pathogens change regularly forming new strains of the pathogen. so memory cells with one strain of flu wont recognise the new strains with different antigens. the strains are immunologically distinct.
examples of antigenic variation
influenza virus, HIV
