Question

How does a naive B cell know not to activate because there is already a memory B cell available?

Answer 1

B cells are produced in the bone marrow, where the initial stages of maturation occur, and travel to the spleen for final steps of maturation into naïve mature B cells

A naive B cell is a B cell that has not been exposed to an antigen.

Once exposed to an antigen, the naive B cell either becomes a memory B cell or a plasma cell that secretes antibodies specific to the antigen that was originally bound. Plasma cells do not last long in the circulation, this is in contrast to memory cells that last for very long periods of time. Memory cells do not secrete antibody until activated by their specific antigen.