Influence of yeast mannan on human neutrophil functions: inhibition of release of myeloperoxidase related to carbohydrate-binding property of the enzyme.

We investigated the possibility that dissolved mannan polysaccharide from Candida may have an inhibitory influence on the host defense mechanisms associated with neutrophils and thereby contribute to the pathogenesis of candidoses. We created a model for this hypothesis by using mannan derived from bakers' yeast (Saccharomyces cerevisiae) and mannan isolated from the serum of a patient with chronic mucocutaneous candidosis. We observed that these mannans inhibited the respiratory burst and release of myeloperoxidase stimulated by phagocytosis of serum-opsonized zymosan in vitro. Mannan did not inhibit release of three other lysosomal enzymes. The selective inhibition of release of myeloperoxidase was attributable to a carbohydrate-binding property of the enzyme, with the mannan causing co-sedimentation of the enzyme with the cellular fraction.