Antigenic differences in the surface mannoproteins of Candida albicans as revealed by monoclonal antibodies
P M Sundstrom1, M R Tam, E J Nichols
1Department of Pathobiology, School of Public Health and Community Medicine, Seattle, Washington 98195.
Abstract:
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.
Insights
Monoclonal antibodies targeting Candida albicans were developed. These antibodies identified mannoproteins on the fungal surface, revealing heterogeneity in Candida albicans mannoproteins.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Candida albicans is an opportunistic fungal pathogen.
- Understanding its surface components is crucial for diagnostics and therapeutics.
Purpose of the Study:
- To develop and characterize monoclonal antibodies against Candida albicans.
- To investigate the heterogeneity of Candida albicans surface mannoproteins.
Main Methods:
- Production of monoclonal antibodies using germ tube-bearing C. albicans blastoconidia.
- Immunofluorescence assays for surface reactivity.
- Immunoprecipitation of metabolically labeled cell digests.
- Crossed immunoelectrophoresis to identify mannoprotein antigens.
- Analysis of reactivity with glycan fractions.
Main Results:
- Four monoclonal antibodies showed broad reactivity with Candida species (C. albicans, C. stellatoidea, C. tropicalis) but not Torulopsis glabrata.
- One antibody reacted with Saccharomyces cerevisiae.
- Antibodies precipitated a ~200 kDa component.
- Immunofluorescence revealed heterogeneous staining patterns on C. albicans surfaces.
- Two antibodies identified mannoprotein antigens via crossed immunoelectrophoresis.
- Three antibodies reacted with the carbohydrate portion of mannoproteins.
Conclusions:
- Monoclonal antibodies were generated against Candida albicans.
- The antibodies highlight heterogeneity in C. albicans surface mannoproteins.
- These antibodies can be valuable tools for studying Candida cell wall components.
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