Adaptive immune system is based on immunological memory.
This system is a specialized sub system of immune system that can eliminate pathogens and prevent their growth in the body.
After its first encounter with the pathogen, it creates an immunological memory that can last up to lifetime and it is highly specific. The memory of the first encounter leads to enhanced response in future with the particular pathogen.
For example, a person who gets affected from measles gets a lifetime protection from the pathogen.
