Fig. 1: Immune response elicited after BCG vaccination-specific effects for MTB.

After BCG vaccine is injected intracutaneously, monocytes, macrophages, and DCs recognize the BCG at the vaccination site and form a strong immune response. A BCG is recognized and internalized by DCs or macrophages. The cell wall or other components of BCG act as PRRs that bind to different ligands, upregulate costimulatory molecules of stimulated cells, and activate anti-TB innate immune response. B Activated DC cells migrate to lymph nodes to activate mycobacterial specific CD4⁺ and CD8⁺ T cells with a Th1 profile, and subsequently induce the secretion of high levels of cytokines, such as IFN-gamma and granzyme. At the same time, B cells that respond to BCG antigens lead to the production of memory cells, plasma cells, and antigen-specific antibodies. Figure was created using BioRender.