<unk> s or<unk> es <unk> s) are transiently formed structures within B cell zone (follicles) in secondary lymphoid organs – lymph nodes, ileal Peyer's patches, and the spleen – where mature B cells are activated, proliferate, differentiate, and mutate their antibody genes (through somatic hypermutation aimed at achieving higher affinity) during a normal immune response; most of the<unk>  B cells (BGC) are removed by tingible body macrophages. The B cells develop dynamically after the activation of follicular B cells by T-dependent antigen. As they undergo rapid and mutative cellular division, B cells of the<unk> 's dark zone are known as<unk> oblasts. Once these B cells have stopped proliferating and moved to the light zone, they are known as<unk> ocytes, and are subjected to selection by follicular helper T (TFH) cells in the presence of follicular dendritic cells (FDCs).<unk> s are an important part of the B cell humoral immune response, acting as<unk> al factories for the generation of affinity matured B cells specialized in producing improved antibodies that effectively recognize antigen (e.g. infectious agents), and for the production of long-lived plasma cells and durable memory B cells.
Germinal center
Germinal matrix
Growth cone
Cortical minicolumn
Root sheath 
Optic stalk
Medulla
Medulla 