2.61 understand that vaccination results in the manufacture of memory cells, which enable future antibody production to the pathogen to occur sooner, faster and in greater quantity

Vaccination is when a harmless or inactive form of a pathogen is injected into the body. It stimulates a response from the immune system with out putting the body at risk.
The pathogen will meet the lymphocyte that has the ability to get rid of it, it will be disposed of. The key thing is, though, that when the lymphocyte divides it will create memory cells. If the same pathogen is ever in the blood stream again (in the case of a real harmful infection) the memory cells will meet it and produce the appropriate anti-bodies making the immune reaction occur sooner and faster meaning a greater quantiy of anti-bodies will be produced from when the pathogen enters the body.