Laminin receptors on Candida albicans germ tubes

Abstract

Recent evidence for the role of laminin in cell adhesion and in the pathogenesis of several bacterial infections has led us to investigate the existence of receptors for this extracellular matrix component in Candida albicans. At first, immunofluorescence demonstrated the presence of laminin-binding sites at the surface of germ tubes. Electron microscopy confirmed this result and permitted precise localization of the binding sites on the outermost fibrillar layer of the germ tube cell wall. By using 1251-radiolabeled laminin, the binding was shown to be saturable and specific, hence demonstrating characteristics of true receptors. Analysis of the data by the Scatchard equation indicated that there were about 8,000 binding sites per cell, with a dissociation constant 48

Inhibition of Candida albicans attachment to extracellular matrix by antibodies which recognize hydrophobic cell wall proteins

“…Comparison of these reports often reveals that several proteins of di¡ering molecular masses can each bind the various ECM proteins. For example, C. albicans wall proteins of 37, 60, 62, 67, and 68 kDa have been observed to bind laminin [15,16]. These molecular masses are very similar to those of proteins reported to bind ¢brinogen [14], ¢bronectin [12], C3d [11,13], and iC3b [48].…”

“…Binding to the extracellular matrix by proteins on the cell surface of microorganisms is considered to play an important role in adhesion (for reviews see [35^38]). C. albicans cells have been shown to bind to several ECM proteins in vitro and in vivo, including ¢bronectin [39^42], laminin [15,16], ¢brinogen [43,44], ¢brin [45], and entactin [46]. Gale et al [47] have cloned a gene, INT1, which encodes an integrin-like protein and was subsequently linked to hyphal growth, virulence and adhesion.…”

Binding of mouse fibrinogen to Candida albicans in vivo

“…In the blood stream and in tissue, the yeast form can interact with host components such as fibrinogen, fibronectin, complement and laminin. Recent reports have described the in vitro ability of C. albicans to bind to these components [1][2][3][4][5][6][7][8][9]. We have demonstrated the expression in vitro of fibrinogen binding factors (FBF) on the cell surface of C. albicans germ tubes but not on blastospores [2,3].…”

“…Four strains of C. albicans were used in this study. Strain 1066 (--ATCC 66369), originally isolated from a case of a Candida septicemia, has been used as the archetype of the species in several of our earlier studies concerning FBF of C. albicans [2,3,6]. The other organisms used in this study were three isolates of C. albicans originally isolated from oral lesions.…”

Identification and immunochemical characterization of a germ tube specific antigen of Candida albicans

“…Evidence has been presented to support the pathogenic involvement of germ tubes [2,3], although the precise relationship between dimorphism and pathogenicity is not understood. Surface-specific molecules of C. albicans germ tubes have been identified using biochemical [4,5] and immunological approaches [6][7][8][9][10][11][12], some of which are involved in the adherence of the fungus to host cells or to prosthetic devices [13][14][15].…”