Adaptive (acquired) immunity refers to antigen-specific defense mechanisms that take several days to become protective and are designed to react with and remove a specific antigen. This is the immunity one develops throughout life.
If pathogens successfully evade the innate response, vertebrates possess a second layer of protection which is activated by the innate response. The immune system adapts its response during an infection to improve its recognition of the pathogen. The improved response is then retained after the pathogen has been eliminated, in the form of an immunological memory, and allows the adaptive immune system to mount faster and stronger attacks each time this pathogen is encountered.
- Pathogen and antigen specific response
- Lag time between exposure and maximal response
- Cell-mediated and humoral components
- Exposure leads to immunological memory
- Only found in jawed vertebrates