EXISTENCE OF BRANCHED SIDE-CHAINS IN THE CELL-WALL MANNAN OF PATHOGENIC YEAST, CANDIDA-ALBICANS - STRUCTURE-ANTIGENICITY RELATIONSHIP BETWEEN THE CELL-WALL MANNANS OF CANDIDA-ALBICANS AND CANDIDA-PARAPSILOSIS

Isolation of side chain oligosaccharides from mannans of Candida albic ans NIH B-792 (serotype B) and Candida parapsilosis IFO 1396 strains h as been conducted by acetolysis under mild conditions. Structural stud y of these oligosaccharides by H-1 and C-13 NMR and methylation analys es indicated the presence of novel branched side chains with the follo wing structures in C. albicans mannan. GRAPHICS It was observed that t he H-1 proton chemical shifts of the second and the third mannose unit s from the reducing terminus in each oligosaccharide are shifted upfie ld by substitution with an alpha-linked mannose unit at position 6 of the 3-O-substituted mannose unit. An agglutination inhibition assay be tween factor 4 serum and cells of Candida stellatoidea IFO 1397 lackin g the beta-1,2-linked mannose unit, with oligosaccharides obtained fro m these mannans, indicated that only the branched oligosaccharides wer e active. This finding suggests that the branched oligosaccharides cor respond to the epitope of antigenic factor 4, The presence of the bran ched structure in other mannans was detected by the characteristic H-1 -H-2-correlated cross-peak of the alpha-1,2-linked mannose unit connec ted with the 3,6-di-O-substituted one by two-dimensional homonuclear H artmann-Hahn spectroscopy.