Adaptive Immune System - Immunological Memory

Immunological Memory

For more details on this topic, see Immunity (medical).

When B cells and T cells are activated some will become memory cells. Throughout the lifetime of an animal these memory cells form a database of effective B and T lymphocytes. Upon interaction with a previously encountered antigen, the appropriate memory cells are selected and activated. In this manner, the second and subsequent exposures to an antigen produce a stronger and faster immune response. This is "adaptive" because the body's immune system prepares itself for future challenges. Immunological memory can either be in the form of passive short-term memory or active long-term memory.