Developing New Anti-Tuberculosis Vaccines: Focus on Adjuvants

Area of Science:

• Immunology
• Vaccinology
• Infectious Diseases

Background:

• Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a leading global cause of death, with the current BCG vaccine showing variable efficacy, especially against pulmonary TB.
• The World Health Organization prioritizes the development of novel TB vaccines to address this significant public health challenge.
• Subunit vaccines offer a promising approach due to improved safety profiles and antigen targeting, but require adjuvants to enhance immunogenicity and optimize delivery.

Purpose of the Study:

• To review adjuvants used in current and preclinical TB vaccine formulations.
• To analyze how these adjuvants influence immune responses, particularly T-helper 1 (Th1) and T-helper 17 (Th17) pathways.
• To discuss the role of adjuvants in enhancing the efficacy of new TB vaccine candidates.

Main Methods:

• Literature review of scientific publications on TB vaccine adjuvants.
• Analysis of preclinical and clinical trial data for TB vaccine candidates incorporating adjuvants.
• Focus on adjuvants that promote Th1 and Th17 immune responses, including polyfunctional CD4+ T cells.

Main Results:

• Adjuvants are essential for increasing immunogenicity, reducing antigen dose, and improving the delivery of subunit TB vaccines.
• Most reviewed adjuvants are effective in promoting the desired Th1 and Th17 immune responses crucial for TB immunity.
• Several adjuvant-containing TB vaccine candidates are progressing through clinical and preclinical development.

Conclusions:

• Adjuvants play a critical role in the development of effective next-generation TB vaccines.
• Current research emphasizes adjuvants that elicit Th1 and Th17 responses, aligning with established immunological targets for TB.
• Further research should explore a broader range of immune parameters to fully understand adjuvant function and establish correlates of protection for TB vaccines.