ABSTRACT
Candida
albicans is a commensal dimorphic yeast of the digestive tract
that causes hematogenously disseminated infections in immunocompromised
individuals. Endogenous invasive candidiasis develops from C.
albicans adhering to the intestinal epithelium. Adherence is
mediated by the cell wall surface, a domain composed essentially of
mannopyranosyl residues bound to proteins, the N-linked moiety of which
comprises sequences of α-1,2- and β-1,2-linked mannose
residues. β-1,2-linked mannosides are also associated with a
glycolipid, phospholipomannan, at the C. albicans surface. In
order to determine the roles of β-1,2 and α-1,2
oligomannosides in the C. albicans-enterocyte interaction, we
developed a model of adhesion of C. albicans VW32 blastospores
to the apical regions of differentiated Caco-2 cells. Preincubation of
yeasts with monoclonal antibodies (MAbs) specific for α-1,2 andβ
-1,2 mannan epitopes resulted in a dose-dependent decrease in
adhesion (50% of the control with a 60-μg/ml MAb
concentration). In competitive assays β-1,2 and α-1,2
tetramannosides were the most potent carbohydrate inhibitors, with
50% inhibitory concentrations of 2.58 and 6.99 mM, respectively.
Immunolocalization on infected monolayers with MAbs specific forα
-1,2 and β-1,2 oligomannosides showed that these
epitopes were shed from the yeast to the enterocyte surface. Taken
together, our data indicate that α-1,2 and β-1,2
oligomannosides are involved in the C. albicans-enterocyte
interaction and participate in the adhesion of the yeasts to the
mucosal
surface.
Characterization of Candida albicans cell wall antigens with monoclonal antibodies.