Inductive microRNA-21 impairs anti-mycobacterial responses by targeting IL-12 and Bcl-2

► BCG infection induce miR-21 de novo expression both in vitro and in vivo. ► miR-21 impairs BCG induced Th1 responses. ► miR-21 reduced IL-12 production from APC and promoted APC apoptosis. ► Il12p35 and Bcl2 to be the direct target of miR-21.