ADHESIN RECEPTOR INTERACTIONS IN THE ATTACHMENT OF CANDIDA-ALBICANS TO HOST EPITHELIAL-CELLS

The ability of Candida albicans to adhere to a variety of host surface s is thought to be an important factor in the pathogenesis of candidos is. Adhesion of the yeast form of the fungus to epithelial cells can i nvolve several kinds of adhesin-receptor interaction. Yeast adhesins a re typically mannoproteins associated with fibrils or fimbriae on the fungal surface. Lectinlike interactions have been identified between t he protein portion of two mannoprotein adhesins and glycosides contain ing L-fucose or N-acetylglucosamine. The fucoside-binding adhesin has been purified and shown to have an affinity for glycosphingolipid rece ptors carrying the H blood-group antigen. A fimbrial adhesin has also been described that binds to gangliosides containing a beta GalNAc(1-4 )beta Gal disaccharide sequence. Other mannoprotein adhesins proposed recently include the factor 6 epitope present on serotype A strains of C, albicans and an integrin analogue. Adhesin expression appears to b e regulated by a number of environmental signals, including osmolarity and the availability of iron and sugars. Additional adhesion-dependen t signals might trigger further responses such as the initiation of mo rphogenesis.