In immunology, a memory B cell (MBC) is a type of B lymphocyte that kinds part of the adaptive immune system. These cells develop inside germinal centers of the secondary lymphoid organs. Memory B cells circulate within the blood stream in a quiescent state, sometimes for decades. Their perform is to memorize the traits of the antigen that activated their mother or father B cell throughout initial infection such that if the memory B cell later encounters the same antigen, it triggers an accelerated and strong secondary immune response. Memory B cells have B cell receptors (BCRs) on their cell membrane, an identical to the one on their mum or dad cell, that permit them to acknowledge antigen and mount a particular antibody response. In a T-cell dependent improvement pathway, naïve follicular B cells are activated by antigen-presenting follicular B helper T cells (TFH) during the preliminary infection, or major immune response. B cells might also be activated by binding overseas antigen in the periphery where they then transfer into the secondary lymphoid organs.

A sign transduced by the binding of the peptide to the B cell causes the cells to migrate to the edge of the follicle bordering the T cell area. The B cells internalize the international peptides, break them down, and express them on class II major histocompatibility complexes (MHCII), which are cell surface proteins. Throughout the secondary lymphoid organs, most of the B cells will enter B-cell follicles the place a germinal heart will kind. Most B cells will ultimately differentiate into plasma cells or memory B cells within the germinal center. The TFHs that express T cell receptors (TCRs) cognate to the peptide (i.e. particular for the peptide-MHCII complex) on the border of the B cell follicle and T-cell zone will bind to the MHCII ligand. The T cells will then express the CD40 ligand (CD40L) molecule and can begin to secrete cytokines which cause the B cells to proliferate and to bear class switch recombination, a mutation within the B cell's genetic coding that changes their immunoglobulin type.

Class switching allows Memory Wave Audio B cells to secrete various kinds of antibodies in future immune responses. The B cells then either differentiate into plasma cells, germinal heart B cells, or memory B cells relying on the expressed transcription factors. The activated B cells that expressed the transcription factor Bcl-6 will enter B-cell follicles and bear germinal heart reactions. Once inside the germinal middle, the B cells endure proliferation, adopted by mutation of the genetic coding region of their BCR, a process generally known as somatic hypermutation. The mutations will both enhance or decrease the affinity of the floor receptor for