Vaccine boosts innate immunity in people with dormant immune cells

Bacillus Calmette-Guérin (BCG) is one of the world's oldest and most widely used vaccines. It was developed in the early 20th century to provide protection from tuberculosis. Surprisingly, this vaccine protects not only against tuberculosis but also reduces the risk for various other infections, through a mechanism called trained immunity. A new study led by Christoph Bock (CeMM and Medical University of Vienna and Mihai Netea (Radboud University Medical Center) found that epigenetic cell states predict whether or not an individual profits from the "wake-up call" to the innate immune system that is provided by the BCG vaccine. This discovery contributes to the development of future therapeutics that induce protective trained immunity. Humans are protected by two branches of the immune system. Innate immunity provides built-in defense against widespread characteristics of bacteria and viruses, while adaptive immunity memorizes individual pathogens that a person has already encountered.