Characterization of a haemolytic factor from Candida albicans

The culture supernatant of Candida albicans promoted the disruption of huma n red blood cells (RBCs). The haemolytic activity was detected in a sugar-r ich fraction (about 200 kDa) from Sephacryl 5-100 chromatography. As the ha emolytic activity was adsorbed by concanavalin A-Sepharose, the haemolytic factor may be a mannoprotein. The activity was inactivated by periodate oxi dation, indicating that the sugar moiety of the mannoprotein played an impo rtant role in the haemolysis. The structure of the sugar moiety of the mann oprotein was identified as a cell-wall mannan by H-1-NMR analysis, and puri fied C. albicans mannan promoted the disruption of RBCs. The binding of man nan to RBCs was demonstrated by flow cytometric analysis and was inhibited by the addition of band 3 protein inhibitor, 4,4'-diisothiocyanatostilbene- 2,2'-disulfonic acid (DIDS). The haemolysis caused by mannan was inhibited by DIDS, SITS (4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid) and bis(sulfosuccinimidyl) suberate, but not by pyridoxal 5-phosphate. Thes e results indicated that a mannoprotein released from C. albicans bound to the band 3 protein on RBCs, thereby promoting their disruption.