Trained immunity: implications for vaccination

The concept that only adaptive immunity can build immunological memory has been challenged in the past decade. Live attenuated vaccines such as the Bacillus Calmette???Gu??rin, measles-containing vaccines, and the oral polio vaccine have been shown to reduce overall mortality beyond their effects attributable to the targeted diseases. After an encounter with a primary stimulus, epigenetic and metabolic reprogramming of bone marrow progenitor cells and functional changes of tissue immune cell populations result in augmented immune responses against a secondary challenge. This process has been termed trained immunity. This review describes the mechanisms leading to trained immunity and summarizes the most important developments from the past few years.

Automated summary

The concept of only adaptive immunity being able to build immunological memory has been challenged in the past decade. It has been shown that live attenuated vaccines can reduce overall mortality beyond their effects on targeted diseases. After encountering a primary stimulus, changes in bone marrow progenitor cells and tissue immune cell populations result in enhanced immune responses against a secondary challenge.