What is the significance of using BCG in this study?

BCG is a live-attenuated vaccine that stimulates an immune response, making it a valuable tool for studying tuberculosis immunity.

How does intranasal administration benefit vaccination?

Intranasal administration targets the respiratory mucosa, which is the primary entry point for respiratory pathogens, enhancing local immunity.

What role do T RM cells play in immunity?

T RM cells provide long-term protection by remaining in tissues and rapidly responding to reinfection.

How was the effectiveness of the vaccination assessed?

Effectiveness was assessed by challenging vaccinated mice with virulent mycobacteria and measuring immune responses.

What are the implications of this research?

This research could lead to improved strategies for tuberculosis vaccination and better understanding of immune memory.

Intranasal Immunization with BCG in a Mouse Model

JoVE Encyclopedia of Experiments

Immunology

0 views • 2:16 min • July 8th, 2025

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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.

For intranasal administration, load a micropipette with 20 microliters of the BCG suspension, and place the anesthetized mouse in the supine position inside the hood. Administer the inoculum dropwise between the two nostrils until the entire 20-microliter volume has been deposited, leaving time between the drops to allow the mouse to inhale the suspension. Then, reload the micropipette with another 20 microliters of bacteria and repeat the administration.

For intranasal challenge with the H37Rv Mycobacterium tuberculosis strain, at the appropriate experimental time point post-vaccination, inoculate the animals with intranasal administration of 40 microliters of the H37Rv bacterial suspension as just demonstrated.