EVIDENCE FOR DIFFERENT MANNOSYLATION PROCESSES INVOLVED IN THE ASSOCIATION OF BETA-1,2-LINKED OLIGOMANNOSIDIC EPITOPES IN CANDIDA-ALBICANS MANNAN AND PHOSPHOLIPOMANNAN

A monoclonal antibody specific for beta-1,2-linked oligomannosides was used to study the association of these residues with Candida albicans mannan and phospholipomannan (PLM) in relation to growth conditions a nd in mannan mutant strains, Double immunofluorescence assays performe d on cells grown under standard conditions indicated a highly heteroge neous cell surface expression of these epitopes in comparison with the homogeneous expression of alpha-linked oligomannosidic epitopes. Grow th in the presence of tunicamycin. which inhibits mannan N-glycosylati on, resulted in an absence of beta-1,2-oligomannosidic epitopes on the cell surface. although PLM synthesis still occurred as shown by autor adiography, Similarly, growth in acidic conditions, which inhibits the incorporation of beta-1,2-oligomannosides in mannan, resulted in an a bsence of beta-1,2-oligomannosidic epitopes at the cell surface, altho ugh they still associated with PLM as shown by Western blotting. Weste rn blots of C. albicans mutant strains with reduced amounts or an abse nce of phosphorus and acid-labile beta-1,2-oligomannosides in their ma nnan confirmed that the association of beta-1,2-linked oligomannosides with mannan and with PLM involves different mannosylation processes.