The cell wall galactomannan antigen from Malassezia furfur and Malassezia pachydermatis contains β-1,6-linked linear galactofuranosyl residues and its detection has diagnostic potential

Abstract

Lipophilic yeasts of the genusMalasseziaare associated with several skin diseases, such as pityriasis versicolor,Malasseziafolliculitis, seborrhoeic dermatitis and atopic dermatitis, and are also increasingly associated with catheter-related fungaemia. The cell wall components of pathogenic micro-organisms behave as an antigen and/or ligand of the innate immune response. Live cells ofMalassezia furfurandMalassezia pachydermatisdid not react with an anti-α-1,2-mannoside antibody. However, they showed a strong hydrophobicity and reactivity with an anti-β-1,3-glucan antibody compared to those ofC. albicans. The cell wall polysaccharides ofM. furfurandM. pachydermatiswere isolated and their structures analysed by1H and13C NMR experiments. Both polysaccharides were shown to beβ-1,6-linked linear galactofuranosyl polymers with a small amount of mannan. The presence of galactomannan on cells ofMalasseziaspecies has not been described previously. The galactomannan did not react with an anti-Aspergillus fumigatusmonoclonal antibody which has specificity forβ-1,5-linked galactofuranosyl residues. An anti-M. furfurantibody strongly reacted with the galactomannans ofM. furfurandM. pachydermatis,but did not react with the galactomannans ofTrichophyton rubrum,A. fumigatusorFonsecaea pedrosoi.The characteristics of the anti-M. furfurantibody suggest that there is potential for diagnosis ofMalasseziainfections by antigen detection.