vaccines and herd immunity Flashcards
what is passive immunity ?
when you don’t create the antibodies yourself . they are introduced into you.pathogen dont enter body so plasma and memory cells are never made .
no long term immunity
give an example of passive immunity
a baby getting antibodies through mothers breastmilk
what is active immunity ?
antibodies created by your own body caused by exposure to antigen or pathogen .
what is natural active immunity ?
following infections and the creation of the bodies own antibodies and memory cells .
what is artificial active immunity
following the introduction of a weakened version of a pathogen or antigens via a vaccine
what happens when the body is exposed to antigens by vaccines ?
activates B cell to go through clonal selection
B cells undergo mitosis to make large number of cells .thee differentiate into plasma cells of B memory cells .plasma cells make antibodies ,B memory cells can divide rapidly into B plasma cells when reinfected with the same pathogen to make large numbers of antibodies rapidly
how long can memory B cells live inside your body ?
decades
how long can plasma cells live in your body ?
they are short lived
how memory B cells protect against pathogens ?
if they collide with an antigen they have encountered before then they divide by mitosis ,making plasma cells .so pathogen is destoryed before any symptoms occur.
what type of immunity do B memory cells provide ?
active
explain herd immunity ?
if enough people in the population are vaccinated then the pathogen can not spread easily among the population and aids protection to those who cant get a vaccine