Dendritic cell interaction with Candida albicans critically depends on N-linked mannan

Area of Science:

• Immunology
• Mycology
• Structural Biology

Background:

• Candida albicans is a common fungal pathogen causing infections in immunocompromised individuals.
• Initial interactions between Candida and host immune cell receptors are poorly understood at a structural level.
• Dendritic cells (DCs) are crucial for anti-Candida immunity, but the specific molecular interactions are unknown.

Purpose of the Study:

• To investigate the molecular mechanisms of Candida albicans recognition and internalization by human dendritic cells.
• To identify the specific fungal structures and host receptors involved in this interaction.
• To determine the impact of these interactions on immune signaling, specifically IL-6 production.

Main Methods:

• Utilized C-type lectins DC-SIGN and macrophage mannose receptor for Candida binding and internalization studies.
• Employed Candida albicans glycosylation mutants to analyze carbohydrate recognition.
• Conducted receptor-specific blocking assays and measured cytokine production (IL-6).

Main Results:

• DC-SIGN and macrophage mannose receptor specifically mediate Candida albicans binding and uptake by human DCs.
• N-linked mannan on Candida albicans is the key carbohydrate structure recognized by these C-type lectins.
• Recognition of N-linked mannan directly influences the production of the proinflammatory cytokine IL-6.

Conclusions:

• Specific C-type lectins on DCs recognize N-linked mannan on Candida albicans, mediating fungal uptake.
• This interaction is critical for initiating an inflammatory immune response, evidenced by IL-6 production.
• Understanding these carbohydrate-lectin interactions provides a basis for developing targeted antifungal therapies.