Fungus Among Us: The Frenemies Within

Area of Science:

• Immunology
• Microbiology
• Mycology

Background:

• Commensal fungi like Candida albicans play a role in host immunity.
• T helper 17 (Th17) cells are crucial for fungal immunity and host defense.
• The cross-reactivity of immune cells can have implications for both beneficial and detrimental immune responses.

Purpose of the Study:

• To investigate the role of Candida albicans in the differentiation of human CD4+ Th17 cells.
• To explore the potential evolutionary advantages of Candida albicans as a commensal organism.
• To understand the mechanisms underlying Th17 cell cross-reactivity to fungal antigens and its clinical relevance.

Main Methods:

• Human CD4+ T cell differentiation assays.
• Fungal antigen stimulation.
• Flow cytometry analysis of Th17 cell populations.
• Assessment of cross-reactivity to heterologous fungal antigens.

Main Results:

• Candida albicans was identified as an inducer of human CD4+ Th17 cell differentiation.
• These induced Th17 cells exhibited heterologous specificity, recognizing antigens from other fungi.
• Th17 cells cross-reactive to Aspergillus fumigatus antigens were associated with exaggerated airway inflammation in humans.

Conclusions:

• Candida albicans promotes the development of broadly specific Th17 cells, potentially conferring evolutionary benefits.
• Immune cross-reactivity driven by Th17 cells can lead to detrimental inflammatory conditions, such as exaggerated airway inflammation.
• Understanding these interactions is crucial for developing therapeutic strategies against fungal infections and related inflammatory diseases.