Intranasal Immunization with BCG in a Mouse Model

Start with an anesthetized mouse and administer a live-attenuated BCG strain of Mycobacterium bovis, which has reduced disease-causing ability, through the mouse's nose.

The injected bacteria stimulate an immune response in the lung tissue and nearby lymph node.

This leads to the generation of effector T cells and B cells that enter the mouse's circulation.

The effector B cells produce antibodies against mycobacteria.

Meanwhile, the effector T cells settle in the lung tissue as resident memory T cells or T_RM cells, providing long-term immunity.

To assess the effectiveness of immunization, administer live, virulent mycobacteria with disease-causing ability through the mouse's nose.

This triggers the activation of T_RM cells in the lung tissue.

Activated T_RM cells release cytokines, attracting other immune cells, including effector B cells.

These B cells secrete antibodies that bind to mycobacteria, enhancing their clearance by neutrophils, indicating successful immunization.