B lymphocyte cell | |
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Details | |
Precursor | Hematopoietic stem cell |
System | Immune system |
Identifiers | |
Latin | lymphocytus B |
MeSH | D001402 |
FMA | 62869 |
Anatomical terms of microanatomy |
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype.[1] They function in the humoral immunity component of the adaptive immune system.[1] B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors.[2] When a naïve or memory B cell is activated by an antigen, it proliferates and differentiates into an antibody-secreting effector cell, known as a plasmablast or plasma cell.[2] In addition, B cells present antigens (they are also classified as professional antigen-presenting cells, APCs) and secrete cytokines.[1] In mammals B cells mature in the bone marrow, which is at the core of most bones.[3] In birds, B cells mature in the bursa of Fabricius, a lymphoid organ where they were first discovered by Chang and Glick,[4] which is why the B stands for bursa and not bone marrow, as commonly believed.
B cells, unlike the other two classes of lymphocytes, T cells and natural killer cells, express B cell receptors (BCRs) on their cell membrane.[1] BCRs allow the B cell to bind to a foreign antigen, against which it will initiate an antibody response.[1] B cell receptors are extremely specific, with all BCRs on a B cell recognizing the same epitope.[5]