Macrophage: A Cell With Many Faces and Functions in Tuberculosis

Area of Science:

• Immunology
• Microbiology
• Cell Biology

Background:

• Mycobacterium tuberculosis (Mtb) causes human tuberculosis (TB), primarily infecting macrophages.
• Latent Mtb infection affects a quarter of the global population, with active TB developing in only 5-10% of cases.
• Macrophage heterogeneity and plasticity play crucial roles in controlling Mtb infection and disease progression.

Purpose of the Study:

• To summarize the interplay between Mtb pathomechanisms and macrophage responses.
• To highlight the implications of macrophage heterogeneity and plasticity in TB pathogenesis.
• To review host defense mechanisms influenced by macrophage functional adaptations.

Main Methods:

• Review of existing literature on Mtb infection and macrophage biology.
• Analysis of Mtb virulence factors and their interaction with host immune cells.
• Examination of macrophage phenotypical variations and their functional consequences.

Main Results:

• Mtb evades innate immune killing by establishing niches within alveolar macrophages (AMs).
• Resident AMs and recruited monocyte-derived macrophages (MDMs) exhibit protective roles.
• Mtb virulence factors can disrupt macrophage homeostasis, promoting pathogen growth in immune-compromised states.

Conclusions:

• Macrophage heterogeneity and plasticity are critical determinants of TB outcomes.
• Understanding these macrophage dynamics is essential for developing effective TB control strategies.
• Targeting Mtb pathomechanisms within macrophages offers potential therapeutic avenues.