Tuberculosis subunit vaccination provides long-term protective immunity characterized by multifunctional CD4 memory T...

Area of Science:

• Immunology
• Vaccinology
• Infectious Diseases

Background:

• Long-term cellular immunity is crucial for combating persistent infectious diseases.
• Existing vaccines often struggle to induce durable, protective immune memory.

Purpose of the Study:

• To evaluate the long-term cellular immunity and protective efficacy of the tuberculosis subunit vaccine Ag85B-ESAT-6/CAF01.
• To characterize the profile of memory T cells induced by the vaccine.

Main Methods:

• Subunit vaccination with Ag85B-ESAT-6/CAF01 in a tuberculosis model.
• Assessment of CD4 T cell responses, including memory cell populations and functionality, via multicolor flow cytometry.
• Evaluation of protection against Mycobacterium tuberculosis challenge.
• Comparison with bacille Calmette-Guérin (BCG) vaccination.

Main Results:

• Ag85B-ESAT-6/CAF01 induced robust CD4 T cell memory sustained for over a year.
• The vaccine-induced memory response provided protection comparable to or better than BCG.
• Long-lived memory cells were predominantly multifunctional (TNF-α+IL-2+ and IFN-γ+TNF-α+IL-2+).
• BCG-induced memory was less multifunctional and biased towards effector cells.

Conclusions:

• Adjuvanted subunit vaccines can induce long-term protective immunity characterized by persistent multifunctional T cells.
• The Ag85B-ESAT-6/CAF01 vaccine effectively sustains multifunctional CD4 T cells post-infection.
• The quality and profile of vaccine-induced immune memory are critical for sustained protection.