Antigenic differences in the surface mannoproteins of Candida albicans as revealed by monoclonal antibodies.

Monoclonal antibodies to Candida albicans were prepared with blastoconidia bearing germ tubes used as the immunogen. Four antibodies reacted by immunofluorescence with surfaces of C. albicans as well as Candida stellatoidea, Candida tropicalis, and several strains of C. albicans, but not with Torulopsis glabrata. One antibody reacted with Saccharomyces cerevisiae. In addition, the monoclonal antibodies precipitated material of approximately 200 kilodaltons when tested against metabolically labeled blastoconidia digests. The monoclonal antibodies exhibited heterogeneous staining of C. albicans surfaces, as shown by immunofluorescence. None of the monoclonal antibodies were specific to germ tubes. More importantly, however, two of the monoclonal antibodies reacted with the mannoprotein precipitin arc of C. albicans that was produced by reference rabbit polyclonal antisera by crossed immunoelectrophoresis, thus linking the heterogeneity seen by immunofluorescence to the heterogeneity in mannoproteins. Finally, three of the monoclonal antibodies reacted with a glycan fraction of cell digests, indicating their reactivity with the carbohydrate portion of the mannoprotein.