A lymphocyte that matures in the bone marrow and then migrates to lymphoid tissues, where a foreign antigen stimulates it to produce antibodies.
All B cells are antigen specific and respond to only one foreign protein. The spleen and lymph nodes contain many B cells that, because of the large amount of blood passing through these organs, become exposed to new antigens. After a B cell comes in contact with an antigen, it differentiates into either a plasma cell or a memory cell, and then proliferates. Plasma cells produce antigen-specific antibodies. Memory cells are available to produce antibodies quickly if the same antigen reappears. Antibody production is part of the humoral immune response of adaptive immunity. The humoral immune response is effective against bacteria, viruses, and other pathogens, and is the basis for vaccination.
SYN: B lymphocyte
See: plasma cell; T cell; antibody; antigen; cytokine; immunoglobulin; vaccination

Main entry:
cell