Immunity And Vaccines Flashcards
(8 cards)
What is the primary immune response?
The immune response from an antigen entering the body activating the immune system
- slow due to low number of B cells able to produce specific antibodies
- results in formation of memory cells which remember the specific antigen and will recognise it if reinfected
What is the secondary immune response?
Activated if the same pathogen re enters the body
- clonal selection occurs faster
- memory B cells are activated and divide into plasma cells which produce specific antibodies
- memory T cells are activated and divide into specific T cells which kill the pathogen
Define active immunity.
When an individual produces its own antibodies after being stimulated by an antigen
Natural - catching a disease
Artificial - vaccination
Define passive immunity
When antibodies produced by another organism are given to an individual
Natural - babies receiving antibodies from breast milk/ placenta
Artificial - if antibodies are injected
Contrast active and passive immunity. (3)
- active requires exposure to antigens, passive does not
- active is long term as the individual produces the antibodies itself however passive is short term, eventually antibodies are broken down
- active takes longer to develop, passive is immediate
How do vaccines work?
Vaccines contain antigens for a particular pathogen , can be free antigens of a dead/ attenuated pathogen
Can be injected or taken orally, stimulates the primary immune response leading to the production of memory cells.
How do vaccines lead to herd immunity?
Reduce the occurrence of a disease if enough people have taken it so that those who are not vaccinated are less likely to catch it.
What are some disadvantages of vaccines? (4)
- antigens could be hydrolysed by enzymes or too large to be absorbed into the blood
- can lead to side effects
- testing on humans could potentially put them at risk
- testing on animals required which some individuals may disagree with
