Primary and Secondary Immune Responses – Flashcards

when a pathogen first enters the body, the antigens on its surface activate the immune system =the primary immune response -eventually the body will produce enough of the right antibody to overcome the infection

there aren't many B lymphocytes to make the antibody needed to bind to the pathogen

the person will show symptoms of the disease

T and B lymphocytes will produce memory cells that remain in the body for a long time

they remember the specific antigen and will recognise it a second time around

record the specific antibodies needed to bind to the antigen

the person has become immune-immune system is able to respond quickly to a second infection

if the pathogen gets into your body again, your immune system quickly kills it before you get ill

if the same pathogen enters your body again, the immune system will produce a quicker, stronger immune response => the secondary immune response

-clonal selection happens faster -memory B lymphocytes divide into plasma cells that produce the right antibody to the antigen -memory T lymphocytes are activated and divide into the correct type of T lymphocytes to kill the cell carrying antigen -often gets rid of the pathogen before you show symptoms

-memory T and B lymphocytes have a limited lifespan -> won't stay forever immune (nooo!) -once all T and B memory cells have died, the person becomes susceptible to by the pathogen again

by being continually exposed to the pathogen, so you continue to make more and memory B and T lymphocytes e.g. people who live in a malarial area who are constantly exposed to the pathogen will build up immunity, but if they move away, they'll have no further expose to it and they may lose their immunity -> if they go back to the area, they'll have to experience a primary response again

to maintain the no. of memory T and B cells in the blood

-both are triggered by invasion of the body by a pathogen -both ultimately get rid of a pathogen -both involve the production of antibodies