The BCG vaccine induces an immune response by stimulating the body's immune system to recognize and attack the bacteria. This is done by introducing the weakened strain of the bacteria, which doesn’t cause disease but trains the immune system to respond more effectively if it encounters the TB bacteria in the future. In cancer treatment, especially non-invasive bladder cancer, BCG is instilled directly into the bladder where it provokes a localized immune response that targets cancer cells.
