Turning foes into permissive hosts: manipulation of macrophage polarization by intracellular bacteria

Area of Science:

• Immunology
• Microbiology
• Cell Biology

Background:

• Macrophages are crucial immune sentinels with antimicrobial functions.
• However, they can serve as intracellular niches for pathogens like Salmonella enterica.
• Macrophage polarization states influence their antibacterial activity and pathogen permissiveness.

Purpose of the Study:

• To review mechanisms by which Salmonella reprograms macrophages.
• To highlight bacterial manipulation of macrophage polarization as a pathogenesis strategy.
• To discuss factors shaping macrophage states and functions.

Main Methods:

• Review of existing literature on bacterial effector mechanisms.
• Analysis of Salmonella's strategy to manipulate host cell polarization.
• Discussion of microenvironmental and ontogenetic influences on macrophages.

Main Results:

• Salmonella and other intracellular bacteria inject virulence effectors into the macrophage cytoplasm.
• These effectors reprogram macrophages, skewing their polarization to create a permissive niche.
• Macrophage reprogramming by bacteria is a conserved pathogenesis strategy.

Conclusions:

• Bacterial manipulation of macrophage polarization is a critical aspect of pathogenesis.
• Understanding macrophage functional diversity is key to developing new therapies.
• Further research is needed to explore the interplay of bacterial effectors, environment, and macrophage ontogeny.