Evidence for avb3 and avb5 integrin-like vitronectin (VN) receptors in Candida albicans and their involvement in Yeast cell adhesion to VN.

The expression of integrin vitronectin (VN) receptors on Candida albicans yeasts and their involvement in the adhesion to VN were investigated. By; immunofluorescence and cytofluorimetric analysis, several antibodies directed against human alpha v, beta 3, beta 5, alpha v beta 3, or alpha v beta 5 integrin positively stained C. albicans yeasts. Biochemical analysis on yeast lysates with anti-human alpha v, beta 3, or beta 5 antibody revealed molecular species of 130, 110, 100, and 84 kDa. The 130-kDa band was identified as Mr,whereas the doublet of 110/100 kDa and the 84-kDa band likely correspond to the beta 3 and beta 5 subunits, respectively. Some 48%-54% of Candida yeasts specifically adhered to VN, and this binding was strongly inhibited by anti-human alpha v, beta 3, alpha v beta 3, and alpha v beta 5 antibodies and by RGD- but not RGE-containing peptides. In addition, VN inhibited C. albicans adherence to a human endothelial cell Une. Thus, C. albicans in the yeast phase expresses VN receptors antigenically related to the vertebrate alpha v beta 3 and alpha v beta 5 integrins, which mediate its adhesion to VN.