B cells

B cells: A type of white blood cell and, more particularly, a key kind of lymphocyte. Many B cells mature into plasma cells, which produce antibodies (proteins) necessary to fight off infections (bacteria, viruses, etc.), while other B cells mature into memory B cells. All of the plasma cells descended from a single B cell produce the same antibody which is directed against the antigen that stimulated it to mature. The same principle holds with memory B cells. Thus, all of the plasma cells and memory cells "remember" the stimulus that led to their formation. The maturation of B cells in birds takes place in an organ called the bursa of Fabricus. Hence, the B (from bursa). B cells in mammals, including humans, mature largely in the bone marrow. So the B is again pertinent.