The innate and adaptive immune systems are closed linked and work together to protect the body against intruders. 

The innate immune system identifies the nature of the pathogen and works quickly to destroy it at the source. It also alerts the adaptive immune system as to the nature of the threat. If the innate immune system fails to destroy the germs at the area of infection, the adaptive immune system takes over and stops the germs from spreading. The adaptive immune system provides a specific, targeted response to a particular antigen and creates immunological memory for future encounters.