Bcellerna

Bcellerna (B cells) are a category of lymphocytes in the adaptive immune system specialized for humoral immunity. In humans and many other vertebrates, Bcellerna originate from hematopoietic stem cells and mature in the bone marrow, after which they migrate to peripheral lymphoid tissues such as the spleen and lymph nodes where they encounter antigens.

Bcellerna express a B cell receptor (BCR), a membrane-bound immunoglobulin that recognizes specific antigens. Upon antigen binding and assistance from helper T cells (for most responses), Bcellerna proliferate and differentiate into plasma cells that secrete antibodies, and memory B cells that respond more rapidly on re-exposure. Activation can be T-dependent or T-independent; class-switch recombination enables antibodies of different isotypes (IgM and IgD on naive B cells; IgG, IgA, IgE after activation).

Subtypes include B1 cells, predominantly in body cavities and producing natural antibodies, and conventional B2 cells (follicular and marginal zone B cells) that populate secondary lymphoid organs. Bcellerna also function as antigen-presenting cells and can secrete cytokines, contributing to the regulation of other immune cells.

Clinical aspects: Bcellerna are central to vaccine-induced immunity and protective antibody responses. Dysregulation can lead to immunodeficiencies or autoimmunity, and malignant B cell diseases include various lymphomas and leukemias. Therapies that target Bcellerna, such as anti-CD20 antibodies, are used to treat these conditions.

See also: Immunology, B cell receptor, Vaccination, Antibodies.