Memory B cell production is a key aspect of the adaptive immune system. The process by which memory B cells are formed involves multiple stages, starting with the first encounter with a new pathogen.
On encountering a new antigen for the first time, naïve B cells with surface receptors that can bind to specific components of the antigen get activated.
The activated naïve B cells undergo clonal expansion where they proliferate rapidly, producing a colony of identical cells. This takes place in the secondary lymphoid organ such as lymph nodes.
Most of the activated B cells differentiate into plasma cells or effector B cells, which are responsible for producing antibodies that can eliminate the invading antigen and neutralize the infection.
A subset of the activated B cells differentiate into memory B cells.
The notable feature of memory B cells is that they are capable of remembering the specific antigen that their naïve counterparts just encountered. In case of a subsequent encounter with the same antigen, memory B cells quickly differentiate into plasma cells, producing large quantities of antibodies to mount a faster and more effective immune response. Memory B cells can persist in the body for a very long time, sometimes for the person’s lifetime.