The component of the immune system in vertebrates involving cells that are modified to attack the specific antigens they encounter, as distinguished from the more nonspecific innate immune system. The adaptive immune system comprises lymphocytes (B cells and T cells) having a small number of genetically encoded proteins that can combine in such a way as to produce an enormous variety of proteins, having the potential to fight any antigen encountered.
The component of the vertebrate immune system involving lymphocytes (B cells and T cells) containing a small number of proteins that combine to produce an enormous variety of distinct proteins capable of recognizing and deactivating specific antigens. It is one of two main components of the immune system, along with the innate immune system.
American Heritage Medicine
(immunology) Activated by the innate immune system, it comprises of particularly specialized, systemic cells and processes that remove or counter pathogenic growth.