Amended structure of side chains in a cell wall mannan from Candida albicans serotype A strain grown in yeast extract-Sabouraud liquid medium under acidic conditions: detection of the branched side chains corresponding to antigenic factor 4

In a previous study, we reported the excess production of alpha-1,3-linked mannose residues with the complete disappearance of beta-1,2-linked mannose residues in cell wall mannans of Candida albicans serotype A strain cells, which were grown in yeast extract-Sabouraud liquid medium at pH 2.0. In the present study, we examined the immunochemical reactivity of the same mannan of NIH A-207 with an enzyme-linked immunosorbent assay (ELISA) using several antisera to antigenic factors of the genus Candida (FAbs) and the structure of the mannan by two-dimensional homonuclear Hartmann-Hahn analysis. The ELISA showed that the mannan reacts to FAb 4 but not to FAbs 13b and 34, which are reported to be antibody factors against linear side chains containing an alpha-1,3-linked mannose residue. In the Hartmann-Hahn analysis, we found two branched side chains, Man alpha 1-2Man alpha 1-3[Man alpha 1-6]Man alpha 1-(2Man alpha 1-)(2)2Man and Man alpha 1-3[Man alpha 1-6]Man alpha 1-(2Man alpha 1-)(2)2Man, instead of the previously reported linear side chains. The branched side chains are oversynthesized under acidic conditions.