Adaptive immunity and how lymphocytes work
Lymphocytes recognize and respond to antigens, which are foreign molecules, and inactivate the foreign cells. They also contribut to immunological memory. They originate from stem cells in the bone marrow. T cells migrate from the bone marrow and mature in the thymus. B cells mature in bone marrow. Recognition occurs when an antigen binds to an antigen receptor. All antigen receptors made by a particular B or T cell are identical and they recognize a small, accessible part of the antigen, called an epitope. Each lymphocyte has a specificity for only one epitope.