Kininogen adsorption to the cell surface of Candida spp.

The invasion of human host by pathogenic microorganisms is often associated with increased kinin production which may occur due to the action of pathogen secretory proteinases or the activation of host's surface-dependent kinin generation cascade, initiated by the adsorption of high molecular weight kininogen (HK) on the pathogen cells. In this work we characterize for the first time the binding of HK by Candida yeasts and analyze this adsorption in terms of intraspecific variation and a dependence on the fungal morphology. The apparent dissociation constants for this interaction were in the order of 10− 7 M and the binding capacity increased in the order: Candida glabrata < Candida parapsilosis < Candida krusei < Candida albicans < Candida tropicalis, in a good correlation with the general fungus pathogenicity. Within one species, the more invasive filamentous forms bound HK stronger than the yeast forms. The binding activity was assigned to a fraction of cell surface mannoproteins which were extracted from yeast cell walls by β-1,3-glucanase and mercaptoethanol treatment.