In vitro binding of Candida albicans yeast cells to human fibronectin

Abstract

The binding of Candida albicans yeast cells to human fibronectin (Fn), a major glycoprotein of mammalian cells, was studied using an in vitro assay. Adherence was quantitated in microtiter dishes coated with Fn to which radiolabeled yeast cells were added. Under optimum conditions of the assay, i.e., 1 mM CaCl2 and 70 micrograms Fn protein, approximately 40% of the radiolabeled yeast cells adhered to the Fn. Adherence to Fn was greater at 30 degrees C than at 4 degrees C and was greater with viable yeast cells than with heat-killed cells. Candida albicans (two strains) and C. tropicalis adhered to Fn to a greater extent than C. pseudotropicalis, C. krusei, or Saccharomyces cerevisiae. Pretreatment of C. albicans with chymotrypsin, pronase, or papain, but not pepsin, decreased adherence to Fn. Blocking experiments using mannan, sugars, or amino sugars were carried out by preabsorbing the Fn with each of the above-mentioned compounds. Candida mannan blocked adherence of C. albicans to Fn. The mannan effect was dose dependent. However, adherence of C. albicans to Fn was not significantly reduced by mannose, glucose, or several other sugars. The role of FN as a receptor for the binding of C. albicans yeast cells to buccal and vaginal epithelial cells was investigated also using an in vitro assay. We determined, using indirect fluorescent antibody techniques, that both buccal and vaginal epithelial cells possessed Fn. In addition, yeast cells, when pretreated with Fn, showed reduced adherence with buccal and vaginal cells when compared with nontreated cells. These studies may indicate a role for Fn in the adherence of C. albicans to buccal and vaginal epithelial cells.

Identification of salivary basic proline-rich proteins as receptors for Candida albicans adhesion

“…An understanding of the structure and function of the molecules involved in this interaction may enable the development of methods to prevent the adherence of Candida, or promote the clearance of Candida cells from the oral cavity. C. albicans cells bind to a number of receptors, including fibronectin (Skerl et al, 1984) and the H sugar sequence found on all blood group substances of the ABO [H] system (Brassart et al, 1991). Adherence of C. albicans cells to a single component of human whole saliva, provisionally identified as low-molecular-mass mucin MG2, and to rat submandibular gland (RSMG) mucin (Hoffman & Haidaris, 1993) has also been demonstrated.…”

Candida albicans expresses a fibronectin receptor antigenically related to 5 1 integrin

“…In the reports in which a solid-phase assay was used, an appropriate specificity control was not always present (Skerl e t al., 1984;Scheld e t al., 1985;Klotz & Smith, 1991).…”

“…albicans is known to bind different ECM proteins such as FN, laminin (LM), or collagens (Skerl e t al., 1984;Bouchara etal., 1990;Klotz & Smith, 1991 ;Klotz, 1992). However, the molecular mechanisms involved in these adhesive interactions are still poorly defined.…”

Experimental Model of Candida Albicans (Serotypes a and B) Adherence in Vitro

“…Most reports in the literature indicate a mannoprotein as the adhesin (9,18,30,33). The receptors of various tissues to which C. albicans binds have not been well characterized, although several investigators have suggested that they may be fibronectins, certain phospholipids, L-fucose, mannose, Nacetyl-D-glucosamine, mucins, laminins, and collagen (9,12,20,40). Because of the importance and the significance of adherence, several in vivo and in vitro models have been developed to quantitate and characterize C. albicans adherence to cellular and inanimate surfaces (4,6,7,9,10,11,13,16,17,18,19,20,22,23,24,26,34,35).…”