adaptive immune system

The adaptive immune system is composed of highly specialized, systemic cells and processes that eliminate pathogenic challenges. Thought to have arisen in the first jawed vertebrates, the adaptive or "specific" immune system is activated by the “non-specific” and evolutionarily older innate immune system (which is the major system of host defense against pathogens in nearly all other living things). It is the adaptive immune response that provides the vertebrate immune system with the ability to recognize and remember specific pathogens (to generate immunity), and to mount stronger attacks each time the pathogen is encountered. This is adaptive immunity because the body's immune system prepares itself for future challenges.
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