Differences in interleukin-1β release-inducing activity of Candida albicans toward dendritic cells and macrophages

Area of Science:

• Immunology
• Microbiology
• Cell Biology

Background:

• Interleukin-1 beta (IL-1β) is a critical proinflammatory cytokine in host defense against fungal infections like candidiasis.
• Understanding how immune cells respond to Candida albicans is vital for developing effective antifungal strategies.

Purpose of the Study:

• To investigate the distinct mechanisms by which Candida albicans triggers IL-1β release from dendritic cells and macrophages.
• To identify key differences in cellular interactions and fungal morphology requirements for IL-1β induction.

Main Methods:

• Utilized two Candida albicans strains: a uridine-auxotrophic strain (CAI4) and a naturally hyphae-forming strain (pACT1-GFP).
• Stimulated LPS-primed murine macrophage and dendritic cell lines with the C. albicans strains.
• Assessed IL-1β release, extracellular ATP levels, and the requirement for direct cell contact and fungal morphological changes.

Main Results:

• Both C. albicans strains induced IL-1β release from dendritic cells.
• Macrophages showed significant IL-1β release only with the hyphae-forming strain (pACT1-GFP), with minimal release from the CAI4 strain.
• Macrophage IL-1β induction required direct contact and morphological transition of C. albicans to hyphae, while dendritic cells did not have this requirement.
• Dead C. albicans induced IL-1β in dendritic cells but not macrophages.

Conclusions:

• Candida albicans employs divergent mechanisms to induce IL-1β release in dendritic cells versus macrophages.
• Differences in extracellular ATP release and fungal morphology significantly influence the immune response in these distinct cell types.