Pathogenicity mechanisms and host response during oral Candida albicans infections

Abstract

Oral candidiasis remains one of the most common forms of Candida infections and occurs if the balance between host, Candida and microbiota is disturbed, e.g., by broad spectrum antibiotics or immunosuppression. In recent years, identification of fungal factors contributing to host cell damage and new insights into host defense mechanisms have significantly extended our understanding of the pathogenesis of oral candidiasis. In this review, we will provide an overview of the pathogenicity mechanisms during oral Candida infections and discuss some approaches by which this knowledge could be transferred into therapeutic approaches.

Keywords::

• adhesion
• damage
• epithelial cells
• immunosuppression
• infection models
• innate immunity
• invasion

Financial & competing interests disclosure

The authors’ own research is supported by the Hans Knöll-Institut (HKI), the Federal Ministry of Education and Research (BMBF: Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC) (to BH and IJ)), the Deutsche Forschungsgemeinschaft (DFG Hu 528/14, 15, 16, and 17 (to BH); JA 1960/1-1 (to IJ); SFB/TR 124 FungiNet (to BH and IJ)), the company Bayer Vital, the Medical Research Council (MR-J008303-1 to JN) and the Biotechnology and Biological Sciences Research Council (BB-J016411-1 to JN). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Candida albicans occurs as a commensal in the oral cavity of healthy humans.

• Oral candidiasis is a frequent fungal infection in patients undergoing prolonged broad-spectrum antibiotic therapy or suffering from immunosuppression.

• Adhesion to epithelial cells, invasion of hyphae into the mucosa and epithelial damage are distinct steps during the pathogenesis of oral candidiasis.

• Distinct fungal factors contribute to these steps.

• The immune response of epithelial cells appears targeted to C. albicans hyphae, which provides a mechanism that may allow mucosal tissues to discriminate between commensal/colonizing and invasive/pathogenic C. albicans.

• Cross talk between epithelial cells and innate immune cells is likely an important protective mechanism in the control of oral candidiasis.

• Th1 and Th17 are key T-cell subsets strongly associated with protection against oral Candida infections.

• The elucidation of pathogenesis of oral candidiasis provides leads for novel therapeutic strategies such immunomodulation.

Notes