Age-specific effects of Bacille Calmette-Guérin (BCG) vaccine on primary and trained innate cytokine production by human newborn monocytes in vitro are accompanied by distinct metabolic activation

Background: Due to their distinct immunity, newborns are at high risk of infection. Epidemiologic studies have linked early life immunization with BCG, the live attenuated vaccine against tuberculosis (TB), to an unanticipated reduction (∼50%) in all-cause mortality, greatly exceeding a reduction in mortality attributable to immunizing solely against TB. These observations suggest BCG induces “heterologous” protection against unrelated pathogens, possibly mediated by vaccine-induced training of innate immune cells that has been posited to have a metabolic basis. Objective: Characterize and compare in vitro BCG-induced primary and …