Host-pathogen-immune interactions in an air-liquid interface airway model.

Area of Science:

• Respiratory infection research
• Cell culture models
• Immunology

Background:

• Air-liquid interface (ALI) models advance host-pathogen interaction studies.
• Existing ALI models lack immune cells, limiting epithelial-immune crosstalk investigation.
• A novel dual-cell ALI model integrates macrophages with airway epithelial cells.

Purpose of the Study:

• To develop and characterize a dual-cell ALI model for studying respiratory infections.
• To investigate early epithelial-immune interactions in a human-relevant system.
• To analyze bacterial colonization and inflammatory responses in the presence of macrophages.

Main Methods:

• Human monocyte-derived macrophages were cultured beneath differentiated airway epithelial cells on transwell inserts with fibronectin coating.
• Epithelial barrier integrity was assessed using transepithelial electrical resistance (TEER).
• Inflammatory signaling (IL-8 secretion) and cellular architecture (confocal microscopy) were evaluated before and after *Pseudomonas aeruginosa* PAO1 infection.

Main Results:

• Macrophages adhered without compromising epithelial barrier integrity.
• Dual-cell cultures showed reduced IL-8 secretion compared to monocultures post-infection, indicating immune modulation.
• Confocal microscopy revealed distinct bacterial growth patterns: clustered in monocultures and dispersed in dual-cell cultures.

Conclusions:

• The dual-cell ALI model facilitates the study of early epithelial-immune interactions during airway infections.
• This system allows for investigation of inflammatory modulation and bacterial colonization dynamics.
• It offers a versatile, human-relevant platform for respiratory host-pathogen interaction research.