STRUCTURAL AND IMMUNOCHEMICAL CHARACTERIZATION OF BETA-1,2-LINKED MANNOBIOSYL PHOSPHATE RESIDUE IN THE CELL-WALL MANNAN OF CANDIDA-GLABRATA

A mannan of Candida glabrata IFO 0622 digested by Arthrobacter exo-alp ha-mannosidase and a beta-1,2-linked mannobiose obtained from the pare nt mannan by acid treatment was analyzed using C-13 nuclear magnetic r esonance spectroscopy. The results show that the beta-1,3 linked manno biosyl residue is esterified to a phosphate group through position C-1 in the alpha-configuration, Man beta 1-2Man alpha 1-HPO3-. The result s of immunochemical assays of these mannans using the commercial antig enic factor sera of the genus Candida (Candida Check, Iatron) indicate that the main recognition site of serum no. 6 in this kit is the mann otetraosyl side-chain Man beta 1-2Man alpha 1-2Man alpha 1-2Man in C. glabrata mannan and also suggest that the phosphate-containing unit (s uch as Man beta 1-2Man alpha 1-HPO3- in this mannan) behaves as one of the antigenic determinants of serum no. 6, but not of serum no. 5. Th erefore, the present and previous findings indicate that serum no. 5 r ecognizes relatively longer beta-1,2-linked oligomannosyl side-chains, Man beta 1-[2Man beta 1-](n) 2Man (n = 1-6), attached to the phosphat e groups previously observed in the cell wall mannans of Candida albic ans, Candida stellatoidea, and Candida tropicalis.