Vaccines Flashcards
Vaccine contains…
antigens which are used to stimulate an immune response artificially. It can be a whole living organism, a dead one, toxoid, attenuated organism or only surface antigens.
Toxoid is…
a harmless version of a toxin.
Attenuated organism…
harmless organism used in vaccines.
Vaccines made from dead organisms are not as…
successful as vaccines made of living organisms.
Living organisms injected inside the body…
slowly replicate, providing many antigens to the body, allowing it to produce memory cells.
Some people do not respond…
to the vaccines. This may be due to a defect in the immune system so it does not produces memory cells.
A poor response to vaccines may be also due to malo…
nutrition, especially protein-energy, so the body does not have enough proteins to produce antibodies or clones of lymphocyte.
People vaccinated with a live virus may pass…
it out in their faeces during primary response and may infect others.
Herd immunity is achieved by…
vaccinating a large number of people at the same time.
Herd immunity interrupts…
the transmission in a population, so that people who are vulnerable are less likely to be exposed to the infection.
Antigenic drift is…
only a minor change in the viral antigen, so memory cells still recognise them.
Antigenic shift is…
a major change in the structure of antigens, so memory cells are not able to recognise it.
Pathogens of malaria and sleeping sickness are…
eukaryotes with much more genes than bacteria and viruses. They have thousands of different antigens on the surface.
Some pathogens can enter the body cells, so…
they are protected against antibodies in plasma.
Some pathogens suppress the immune system by…
parasitising the white blood cells.
