EVIDENCE FOR THE PRESENCE OF IMMUNOGLOBULIN-E ANTIBODIES SPECIFIC TO THE CELL-WALL PHOSPHOMANNOPROTEINS OF CANDIDA-ALBICANS IN PATIENTS WITH ALLERGIES

To determine the major antigenic component of Candida albicans against immunoglobulin E (IgE) antibodies in the sera of patients with allerg ies who were positive for IgE antibodies to C. albicans crude antigen in a CAP system, phosphomannoproteins (CAMP/A or CAMP/B for serotype A or B strain, respectively) and their acid-stable portions (CAMP-S/A o r CAMP-S/B) were isolated from beta-mercaptoethanol (2-ME) extracts of C. albicans cells of serotypes A and B, and IgE antibodies against th ese components were compared with those against protein complex and en olase (CAE) fractions isolated from C, albicans cells, The dot blot te st, which was used to detect IgE antibodies to the C, albicans antigen s, showed that IgE antibodies to the 2-ME extract and phosphomannoprot ein fractions were present in the sera of 98.0% (2-ME extract), 96.8% (CAMP/A), 93.2% (CAMP-S/A), 97.2% (CAMP/B), and 81.5% (CAMP-S/B) of th e patients, whereas IgE antibodies to the protein complex and CAE frac tions were found in the sera of 73.6 and 48.8% of the patients, respec tively, The extent of IgF binding to the 2-ME extract and phosphomanno proteins was well correlated with the fluorescence intensities estimat ed with the CAP system, Furthermore, the results obtained from the inh ibition experiment with the CAP system indicated that the binding of I gE antibodies to Candida antigens is strongly inhibited by the phospho mannoprotein fraction and is an indication that the serum of the patie nts contained IgE antibodies specific to the cell wall phosphomannopro teins of C. albicans. Finally, an initial chemical analysis indicated that the epitopes for IgE antibodies on the phosphomannoproteins is a carbohydrate portion, since the ability of CAMP/A to inhibit the bindi ng of IgE antibodies to the homologous CAMP/A was destroyed after oxid ation by sodium periodate but not after digestion with proteinase K.