Fungal cell wall mannan (Mannan)

Fungal cell wall mannans are complex, highly branched polysaccharides composed primarily of mannose units, forming the outermost layer of the fungal cell wall in species such as Candida albicans and Saccharomyces cerevisiae. They are covalently linked to proteins, forming mannoproteins that play a vital role in maintaining cell wall porosity, providing structural rigidity, and facilitating adherence to host tissues. As a major Pathogen-Associated Molecular Pattern (PAMP), mannans are the primary targets for host innate immune recognition via C-type lectin receptors, which orchestrate the antifungal immune response. In clinical practice, the detection of circulating mannan antigens and anti-mannan antibodies serves as a critical diagnostic biomarker for invasive candidiasis. While traditional antifungals focus on ergosterol or beta-glucan, mannans are being actively investigated as targets for novel immunotherapies and glycoconjugate vaccines due to their high surface exposure and essential role in fungal pathogenicity.

Other names

PhosphomannanO-linked mannanN-linked mannanMannan-protein complexGalactomannan

Mannans serve as ligands for Pattern Recognition Receptors (PRRs) such as Dectin-2, Mincle, and the Mannose Receptor (CD206), triggering pro-inflammatory cytokine production and phagocytosis. Therapeutic strategies involve using mannans as vaccine antigens or targeting them with monoclonal antibodies to enhance opsonization and fungal clearance.