Immune system stimulation via live attenuated Mycobacterium bovis (Live attenuated M. bovis)

Live attenuated Mycobacterium bovis, most notably in the form of the Bacillus Calmette–Guérin (BCG) vaccine and other engineered strains, is used to stimulate the immune system for protection against tuberculosis (TB) and related mycobacterial infections. The immunostimulatory effect arises from both innate and adaptive immune responses triggered by viable bacteria or their secreted products. Upon administration, live attenuated M. bovis interacts with antigen-presenting cells (APCs), such as macrophages and dendritic cells. These cells recognize mycobacterial components through pattern recognition receptors (PRRs), including C-type lectin receptors and Toll-like receptors. This leads to secretion of pro-inflammatory cytokines like IL-1β, IFN-γ, TNF-α, and chemokines that recruit additional immune cells. The presentation of mycobacterial antigens by APCs stimulates T cell responses, primarily CD4+ Th1-type T cells that produce IFN-γ critical for controlling intracellular pathogens like M. bovis. Recent research has focused on genetically modified live attenuated strains lacking specific virulence genes to improve safety while maintaining immunogenicity.

Other names

BCG vaccineBacillus Calmette–Guérin vaccineLive attenuated Mycobacterium bovisAttenuated M. bovis

Activation of innate and adaptive immunity via PRRs on APCs leading to cytokine production and T cell activation.