Blymphocytes

B-lymphocytes, commonly referred to as B cells, are a type of white blood cell derived from hematopoietic stem cells in the bone marrow. They play a central role in the adaptive immune system, primarily responsible for humoral immunity—the immune response mediated by antibodies. Unlike innate immune cells, B cells undergo maturation and differentiation in response to specific antigens, allowing them to recognize and target particular pathogens with high specificity.

During their development in the bone marrow, B cells undergo a process called V(D)J recombination, which rearranges their immunoglobulin genes to produce diverse antibody receptors on their surface. This diversity enables B cells to recognize an extensive array of foreign substances, such as bacteria, viruses, and toxins. Once mature, B cells circulate through the bloodstream and lymphatic system, patrolling for antigens.

Upon encountering their specific antigen, B cells become activated, typically with the help of T-helper cells. This activation triggers their proliferation and differentiation into either plasma cells or memory B cells. Plasma cells are short-lived but highly efficient producers of antibodies, which neutralize pathogens by marking them for destruction by other immune cells or preventing their invasion of host cells. Memory B cells, on the other hand, persist long-term and provide rapid, robust responses upon re-exposure to the same antigen, contributing to immunological memory.

B cells also contribute to immune regulation by producing cytokines and interacting with other immune cells. Deficiencies or dysfunctions in B cell function can lead to increased susceptibility to infections or autoimmune diseases, where the immune system mistakenly targets the body’s own tissues. Conditions such as common variable immunodeficiency (CVID) and certain forms of lymphoma highlight the importance of B cell regulation in maintaining immune homeostasis.