IMMUNOLOGICAL MEMORY AND PROTECTIVE IMMUNITY - UNDERSTANDING THEIR RELATION

The immune system can remember, sometimes for a lifetime, the identity of a pathogen. Understanding how this is accomplished has fascinated immunologists and microbiologists for many years, but there is still c onsiderable debate regarding the mechanisms by which long-term immunit y is maintained. Some of the controversy stems from a failure to disti nguish between effector and memory cells and to define their roles in conferring protection against disease. Here the current understanding of the cellular basis of immune memory is reviewed and the relative co ntributions made to protective immunity by memory and effector T and B cells are examined.