Thinking Outside the Box: Innate- and B Cell-Memory Responses as Novel Protective Mechanisms Against Tuberculosis

Area of Science:

• Immunology
• Vaccinology
• Infectious Diseases

Background:

• Tuberculosis (TB) remains the deadliest infectious disease globally, with vaccine development hindered by limited efficacy.
• Traditional TB vaccine strategies primarily focus on interferon-gamma (IFN-γ)-mediated CD4+ T cell memory responses as correlates of protection.
• Emerging evidence suggests that other immune cells may also play a crucial role in protective immunity against Mycobacterium tuberculosis (Mtb).

Purpose of the Study:

• To review and summarize the memory responses of innate immune cells and B cells against Mtb.
• To propose these non-T cell immune compartments as novel correlates of protection for TB.
• To highlight their potential for future TB vaccine development, especially in co-infected populations.

Main Methods:

• Literature review and synthesis of existing research on immune memory in TB.
• Analysis of studies investigating innate immune cells (macrophages, NK cells, ILCs) and B cells in Mtb infection.
• Discussion of the implications for TB vaccine design and control strategies.

Main Results:

• Memory-like features in macrophages, myeloid precursors, NK cells, and ILCs contribute to protective immunity against Mtb.
• B cell memory responses exhibit distinct dynamics across the TB clinical spectrum, indicating their involvement in human TB.
• These innate and B cell responses represent potential novel correlates of protection beyond CD4+ T cells.

Conclusions:

• Rethinking TB vaccine targets beyond CD4+ T cells is essential for enhanced efficacy.
• Innate immune cells and B cells offer promising avenues for novel TB vaccine development.
• Harnessing these immune compartments could improve control of the global TB epidemic, particularly for HIV co-infected individuals.