Structural analysis of phospho- d-mannan-protein complexes isolated from yeast and mold form cells of Candida albicans NIH A-207 serotype a strain

Abstract

The immunochemical properties between phospho- d-mannan-protein complexes of yeast (Y) and mycelial (M) forms of Candida albicans NIH A-207 (serotype A) strain were compared. Hydrolysis of the Y-form complex gave a mixture of β-(1→2)-linked d-mannooligosaccharides consisting mainly of tri- and tetra-ose, whereas the M-form complex gave preponderantly d-mannose. The antiserum against Y-form cells exhibited a lower reactivity with the M-form than with the Y-form complex, whereas the antiserum to M-form cells could not distinguish significantly between both complexes. Moreover, these acid-modified complexes showed lower antibody-precipitating effect than each corresponding intact complex against antisera of Y- and M-form cells. Digestion of the acid-modified Y- and M-form complexes with the Arthrobacter GJM-1 strain α- d-mannosidase yielded 35- and 40-% degradation products, respectively. Acetolysis of each modified complex under mild conditions gave the same d-mannohexaose, β- d-Man p-(1→2)-β- d-Man p-(1→2)-α- d-Man p-(1→2)-α- d-Man p-(1→2)-α- d-Man p-(1→2)- d-Man. Because the complexes of Y- and M-form cells of C. albicans NIH B-792 (serotype B) strain did not give any hexaose fraction containing β-(1→2) linkages, the presence of this hexaose can be regarded as one of the dominant characteristics of the serotype-A specificity of C. albicans spp.