develops from capable of output of professional antigen presenting cell mature B cell mature B-lymphocyte A mature B cell is a critical component of the body's immune system, with different mature B cell subsets providing distinct functions in both adaptive and innate humoral immune responses. The primary role of these cells in the immune function is to produce antibodies or immunoglobulins which serve to neutralize or aid in the destruction of pathogens – microbes, viruses or any toxin that is harmful to the body. Mature B cells develop from immature B cells that have migrated from the bone marrow to the spleen where they differentiate through transitional B cell stages (called T1 and T2). Following antigen activation, mature B cells then undergo further developmental stages. Before encountering a specific antigen, mature B cells are called ‘naïve’ B cells. Due to the high variability of B cell receptors (BCR) even within the same individual, each naive B cell is capable of recognizing a unique molecular structure, leading to an immensely diverse repertoire of these cells ready to react against a wide array of pathogenic threats. Mature B cell subsets include follicular and marginal zone B cells, so named because they are enriched in the follicles and marginal zones of the spleen, respectively, although they are not confined to these compartments. Follicular B cells depend upon T cells for activation against specific antigens, and this reaction forms germinal centers in which the follicular B cells differentiate into germinal center B cells. Following class switch recombination and somatic hypermutation, these cells can differentiate into plasma cells, which secrete high-affinity antibodies, or memory B cells, which contribute to immunological memory when re-challenged by the same antigen. Marginal zone B cells can function as antigen-presenting cells and can also rapidly respond to blood-borne antigens by differentiating into antibody-secreting plasma cells with short half-lives. In addition to follicular and marginal zone B cells, there is a third population of mature B cells, known as B1 cells, which have have a distinct haematopoietic origin in the fetal liver and are located in a number of tissues including the spleen, intestine, and the pleural and peritoneal cavities. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) mature B lymphocyte mature B-cell Mature B cells are also reportedly CD10-negative, CD19-positive, CD22-positive, CD34-negative, CD48-positive, CD79a-positive, CD84-positive, CD127-negative, CD352-positive, RAG-negative, TdT-negative, Vpre-B-negative, and pre-BCR-negative. Transcription factors expressed: Pax5-positive. A B cell that is mature, having left the bone marrow. Initially, these cells are IgM-positive and IgD-positive, and they can be activated by antigen. https://cellxgene.cziscience.com/cellguide/CL_0000785 ZFA:0009331 immature B cell precursor B cell transitional stage B cell B cell, CD19-positive mature B cell differentiation antigen processing and presentation of peptide or polysaccharide antigen via MHC class II B cell activation