B cell

Basic B cell function: bind to an antigen, receive help from a cognate helper T cell, and differentiate into a plasma cell that secretes large amounts of antibodies
3D rendering of a B cell

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 by secreting antibodies.[1] Additionally, B cells present antigen (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.[2] In birds, B cells mature in the bursa of Fabricius, a lymphoid organ. (The "B" from B cells comes from the name of this organ, where it was first discovered by Chang and Glick,[2] and not from 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 specific antigen, against which it will initiate an antibody response.[1]


B cells develop from hematopoietic stem cells (HSCs) that originate from bone marrow.[3] HSCs first differentiate into multipotent progenitor (MPP) cells, then common lymphoid progenitor (CLP) cells.[3] From here, their development into B cells occurs in several stages (shown in image to the right), each marked by various gene expression patterns and immunoglobulin H chain and L chain gene loci arrangements, the latter due to B cells undergoing V(D)J recombination as they develop.[4]

Early B cell development: from stem cell to immature B cell

B cells undergo two types of selection while developing in the bone marrow to ensure proper development. Positive selection occurs through antigen-independent signaling involving both the pre-BCR and the BCR.[5][6] If these receptors do not bind to their ligand, B cells do not receive the proper signals and cease to develop.[5][6] Negative selection occurs through the binding of self-antigen with the BCR; If the BCR can bind strongly to self-antigen, then the B cell undergoes one of four fates: clonal deletion, receptor editing, anergy, or ignorance (B cell ignores signal and continues development).[6] This negative selection process leads to a state of central tolerance, in which the mature B cells don't bind with self antigens present in the bone marrow.[4]

To complete development, immature B cells migrate from the bone marrow into the spleen as transitional B cells, passing through two transitional stages: T1 and T2.[7] Throughout their migration to the spleen and after spleen entry, they are considered T1 B cells.[8] Within the spleen, T1 B cells transition to T2 B cells.[8] T2 B cells differentiate into either follicular (FO) B cells or marginal zone (MZ) B cells depending on signals received through the BCR and other receptors.[9] Once differentiated, they are now considered mature B cells, or naive B cells.[8]

Transitional B cell development: from immature B cell to MZ B cell or mature (FO) B cell

While immature and during the T1 phase, B cells express BCR of class IgG, but BCR expression changes to the classes IgM and IgD after transition into the T2 phase and while mature up to activation.[8]

Other Languages
العربية: خلية بائية
български: B клетка
bosanski: B-ćelija
català: Limfòcit B
čeština: B-lymfocyt
dansk: B-celle
Deutsch: B-Lymphozyt
ދިވެހިބަސް: ބީ ލިމްފަސައިޓް
español: Linfocito B
français: Lymphocyte B
galego: Linfocito B
한국어: B세포
Bahasa Indonesia: Sel B
íslenska: B-eitilfruma
italiano: Linfocita B
עברית: לימפוציט B
ქართული: B ლიმფოციტი
lietuvių: B limfocitai
magyar: B-limfocita
മലയാളം: ബി-ലസികാണു
монгол: В эс
Nederlands: B-cel
日本語: B細胞
norsk: B-celle
occitan: Linfocit B
polski: Limfocyty B
português: Linfócito B
română: Celule B
русский: B-лимфоциты
Simple English: B cell
slovenčina: B-lymfocyt
slovenščina: Limfocit B
suomi: B-solu
svenska: B-cell
தமிழ்: பி உயிரணு
Türkçe: B hücresi
українська: B-лімфоцити
中文: B细胞