From what I understand, once the infection is handled, some of the B cells capable of producing the correct antigens are stored for the long-term in the lymph nodes.
They will start multiplying again upon encountering the pathogen again.
What I don't understand is how can these cells, that should be in relatively small numbers, can effectively encounter the pathogen ? Do all pathogens travel to the lymph nodes? Do the memory B cells travel out and encounter pathogens?