Eosinophils as drivers of bacterial immunomodulation and persistence

Area of Science:

• Immunology
• Microbiology
• Pathogenesis

Background:

• Eosinophils traditionally associated with parasitic infections and disease.
• Emerging evidence reveals eosinophils' crucial role in mucosal homeostasis.
• Eosinophils exhibit diverse functions during infections, impacting pathogen persistence and allergic responses.

Purpose of the Study:

• To review the role of eosinophils as targets of bacterial exploitation.
• To highlight the mechanism by which *Bordetella bronchiseptica* manipulates eosinophils.
• To explore the implications for chronic mucosal infections and therapeutic development.

Main Methods:

• Review of existing literature on eosinophil function in mucosal infections.
• Focus on *Bordetella* spp., particularly *Bordetella bronchiseptica*.
• Analysis of the *btrS*-mediated mechanism and its effect on eosinophil interaction.

Main Results:

• *Bordetella bronchiseptica* interaction with eosinophils enhances pathogen persistence.
• This interaction delays adaptive immune responses, particularly in the absence of functional *btrS* signaling.
• Wild-type *Bordetella* spp. effectively obscure the true function of eosinophils during infection.

Conclusions:

• Eosinophils are exploited by bacteria to facilitate persistence and chronic infections at mucosal sites.
• The sigma factor BtrS plays a pivotal role in orchestrating eosinophil immunomodulation during pulmonary infection.
• Targeting eosinophil-bacterial interactions presents novel therapeutic strategies for mucosal pathogens.