How do B-Lymphocytes Work?

B-Lymphocytes remain in the bone marrow until they mature and then spread throughout the body, concentrating in the lymph nodes and the spleen.They express a specific intrinsic protein called a B-cell receptor, each B-lymphocyte has a different shaped receptor. This receptor can bind antigens floating in the blood plasma.The binding of an antigen to a b-cell receptor is insufficient to stimulate a response. The binding of a T-helper cell is also required to activate the B-cell.ActivationBinding of an antigen stimulates endocytosis and antigen presentation via an MHC II (Major Histocompatibility Complex 2) molecule.Activated B-Cells then undergo clonal expansion (the production of identical B-cells by mitosis)Some B-Cells can then differentiate into plasma cells which produce antibodies very quickly. The antibodies are secreted into the blood and lymph systems.They do not live long and they are specific to the antigen that was originally recognised.Other B-Cells differentiate into memory cells. They remain circulating in the body for long periods of time.If the same antigen is reintroduced, memory cells divide rapidly and develop into plasma cells and more memory cells.