Alpha-mannan (Mn) (Mn)

Alpha-mannan is a complex, highly branched polysaccharide that serves as a major structural component of the outer cell wall in Candida species, including Candida albicans (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10535344/). It consists of an alpha-1,6-linked mannose backbone with side chains of alpha-1,2 and alpha-1,3-linked mannose residues, often modified with phosphodiester-linked beta-1,2-oligomannosides (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5659167/). Biologically, alpha-mannan is essential for maintaining cell wall integrity, facilitating adhesion to host tissues, and masking the inner beta-glucan layer from immune detection (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5659167/). It acts as a key pathogen-associated molecular pattern (PAMP) recognized by host receptors such as Dectin-2 and the mannose receptor, which are critical for initiating the antifungal immune response (https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.02547/full). In clinical settings, alpha-mannan is a vital biomarker for diagnosing invasive candidiasis through the detection of circulating mannan antigens and corresponding antibodies (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11711444/). Furthermore, it is a primary target for experimental vaccines and monoclonal antibodies, such as MAb B6.1, designed to enhance host defense and neutralize fungal virulence factors (https://pubmed.ncbi.nlm.nih.gov/10228070/).

Other names

MannanCandida mannanPhosphomannanN-linked mannanFungal mannanAlpha-linked mannanAlpha-mannan in Candida spp. cell wall

Drugs and immunotherapies targeting alpha-mannan work by opsonizing fungal cells to promote phagocytosis, neutralizing the immunosuppressive effects of circulating mannan, or enzymatically disrupting the cell wall and biofilm matrix to enhance the efficacy of other antifungal agents.