Bacillus Calmette–Guérin-induced immune activation (BCG-induced immune activation)

Bacillus Calmette–Guérin (BCG)-induced immune activation refers to the broad immunological response triggered by the BCG vaccine. This activation involves both innate and adaptive arms of the immune system, leading to enhanced protection against Mycobacterium tuberculosis and unrelated pathogens through "trained immunity." Key mechanisms include activation of innate immune cells (monocytes, macrophages, neutrophils, dendritic cells), epigenetic reprogramming (H3K4 trimethylation), metabolic reprogramming (increased aerobic glycolysis), and T cell responses (CD8+, CD4+, Tregs). It results in enhanced resistance to pathogens and potential regulatory effects relevant for certain autoimmune diseases. Besides TB vaccination, it's used intravesically for bladder cancer immunotherapy and studied for off-target protective effects.

Other names

BCG vaccinationBCG immunotherapyBCG-mediated immune responseTrained immunity induced by BCGOff-target effects of BCG

Activation of innate and adaptive immune responses via multiple pathways, including NOD2 signaling, cytokine release, and epigenetic reprogramming, leading to trained immunity and enhanced resistance to pathogens.