Immunochemical determinant of Candida parapsilosis.

Acetolysis of Candida parapsilosis cell-wall D-mannan, obtained by alkali extraction and purified as a copper complex, gave six oligosaccharides by Bio-Gel P-2 filtration. Their chemical structure was examined by 1H-n.m.r. spectroscopy, methylation analysis, and partial acid hydrolysis. The structures of the penta- and hexa-saccharide were alpha-D-Manp-(1 leads to 3)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-D-Man (M5) and alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 3)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-alpha-D-Manp-(1 leads to 2)-D-Man (M6), respectively. Inhibition of the oligosaccharides with anti-C. parapsilosis serum and homologous D-mannan indicated that although M5 and M6 exhibited strong inhibitory-activity, M6 was the more effective inhibitor, and suggested that M6 may be the immunodominant or may be responsible for the specificity of C. parapsilosis mannan in the precipitin-reaction system, or both.