The iC3b Receptor on Candida albicans: Subcellular Localization and Modulation of Receptor Expression by Glucose

Publisher Website
Google Scholar
Abstract
Patient isolates of Candida albicans from blood, urine, or mucosal sites express a surface receptor for C3 fragment iC3b that is recognized by monoclonal antibodies (Mab) directed against .alpha.-chain epitopes of the neutrophil iC3b receptors, also known as the type 3 complement receptor (CR3) or CD11blCD18. Because 60% of these patients were hyperglycemic, the effect of glucose on receptor expression was investigated. As assessed by flow cytometry, yeasts grown in 20 mM D-glucose exhibited a four-to six-fold increase in receptor expression compared with yeasts grown in 20 mM L-glutamate. Receptor expression increased as glucose concentration rose from 0 to (equivalent to plasma glucose concentrations of 0-360 mg/dl). Augmentation of receptor expression by growth in glucose led to significant inhibition of phagocytosis compared with that of organisms grown in equimolar, L-glutamate. SDS-PAGE, Western blotting, and immunodetection of extracts of yeast cell wall, membrane, and cytosol disclosed a protein of 165 kDa in membrane and cytosolic extracts, consistent with the published Mr of the .alpha.-chain of neutrophil CR3. These studies provide a mechanism to explain the predilection of C. albicans to infect the hyperglycemic host.

This publication has 14 references indexed in Scilit: