A person is injected with a weakened or dead strain of the pathogen, which is incapable of multiplying (it's harmless).
The antigens trigger the production of specific antibodies by the white blood cells.
Long after the pathogen has been dealt with, the white blood cells remain in the blood (memory cells are produced). This means that more antibodies can be produced very quickly if the same pathogen is detected again.
Comments
No comments have yet been made