Antibody

A protein referred to as immunoglobulin and is derived from lymphocytes originating from the bone marrow (B cells). This form of immunity is essential for extracellular pathogens. Small disease-fighting proteins produced by certain types of cells called 'B cells'. The proteins are made in response to 'foreign' particles such as bacteria or viruses. These antibodies bind with certain proteins (antigens) on foreign particles like bacteria, to help inactivate them. See also antigen. A protein produced by the immune system to protect the body from disease caused by infectious agents (bacteria, viruses). Proteins produced by the immune system in response to antigens; an important component of the immune system,