Biochemical characterization of cell surface components of Candida albicans
Résumé
Extracellular material (ECM) was isolated from media in which yeast phase Candida albicans of unknown serotype was grown. Cold 95% ethanol precipitated the ECM and upon Sephadex G-50 chromatography, high and low molecular weight components were identified. They consisted of ECM 1 (30,000 Mr), ECM 2A (4,500-6,000 Mr), and ECM 2B (3,800 Mr). The ECM 2B was separated into two components upon ion exchange chromatography. Glucose and mannose are its carbohydrate moieties and proline, lysine and glutamic acid are its major amino acids. It appears to have more protein content than ECM 2B2 as evidenced by absorbance at 2 80 nm. ECM 2B2 contains only mannose and some protein composed mostly of proline, threonine and alanine. The components are neither strain-specific, nor produced only during yeast phase growth.
The ECM were compared to material released from the cell surface upon treatment of whole cells with the nonspecific protease papain, and the disulfide bond reducer, dithiothreitol. An ECM 2A is produced upon both treatments. ECM 2B1 closely resembles a low molecular weight component produced upon DTT treatment, and ECM 2B2 is similar to the papain released molecule. The ECM appears to be present either on or within the cell surface of Candida albicans.
The ECM did not appear to be strongly antigenic, although unpurified media did induce an antibody response.