Hyphal cells of Candida albicans bind to human
hemoglobin, but not yeast cells. The amount of
hemoglobin receptor is significantly higher in hyphal cells than on yeast cells. Only the hyphal cells of C. albicans use
hemoglobin as a source of
iron. The culture supernatant of C. albicans promoted the disruption of human red blood cells (RBC). Hemolytic activity was detected in a
sugar-rich fraction (about 200 kDa) purified by Sephacryl S-100 chromatography. As the hemolytic activity was adsorbed by
concanavalin A (
Con A)-Sepharose, the hemolytic factor might be a mannoprotein. The activity was inactivated by
periodate oxidation, indicating that the
sugar moiety of the mannoprotein plays an important role in
hemolysis. The structure of the
sugar moiety of the mannoprotein was identified as a cell wall
mannan by 1H-NMR analysis, and purified C. albicans
mannan promoted the disruption of RBC. The binding of
mannan to RBC was demonstrated by flow cytometric analysis and was inhibited by the addition of the
band 3 protein inhibitor, 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic
acid (
DIDS). The
hemolysis caused by
mannan is inhibited by
DIDS, 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulfonic
acid, and
Bis (sulfosuccinimidyl) suberate, but not by pyridoxal-5'-phosphate. A new
platinum derivative of the form
H[Pt(IV) (Hdigly)Cl2(OH)2] (Hdigly =
glycylglycine) has candidacidal activity 10-fold lower than that of
cisplatin.