Research progress and application in trained immunity induced by Mycobacterium bovis BCG

Abstract:

Trained immunity, a functional state of the innate immune response, is characterized by epigenetic reprogramming and metabolic reprogramming of innate immune cells. Stimuli such as vaccines and microorganisms or their products can stimulate the trained immunity of innate immune cells, such as monocytes, neutrophils, and bone marrow stem cells. The re-stimulation can enhance the immune responses of innate immune cells to microbial pathogens. Mycobacterium bovis Bacillus Calmette-Guérin (BCG) and β-glucan (the main cell wall component of Candida albicans) can activate the nuclear factor-κB (NF-κB) pathway of innate immune cells or dendritic cell-associated C-type lectin 1/protein kinase B/mammalian target of rapamycin/hypoxia-inducible factor 1-alpha (Dectin-1/Akt/mTOR/HIF-1α) signaling pathway to regulate the metabolic reprogramming and epigenetic reprogramming, thereby inducing trained immunity. The discovery of trained immunity in innate immune cells provides a new direction for the research and development of new vaccines, the treatment strategies of immune deficiency, and the regulation of autoinflammatory diseases. Therefore, understanding the cytological mechanisms of trained immunity is of great significance for the prevention of unknown diseases.

Key words:trained immunity;innate immune cells;Bacillus Calmette-Gué;rin (BCG)