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Comparative immunochemical studies of different antigens of deep mycosis pathogens
Abstract:
The disintegration of cells of Coccidioides immitis, Histoplasma capsulatum, Blastomyces dermatitidis and Candida albicans by ultrasonical treatment, repeated freezing-thawing or mechanical methods permitted to obtain antigens with a high protein content. The treatment of these fungal cells with beta-naphthol, ethanol, glycerine or alkali makes it possible to isolate antigens containing mainly polysaccharides. The studied antigens turned out to be complex compounds. Proteins, glycoproteins, nucleoproteins and small quantities of phosphorus and nucleic acids were revealed in their composition. The protein-rich antigens were most active as inductors of a cellular and humoral immune response. These preparations turned out to be the most active and specific for DH testing. The polysaccharide-rich antigens were highly active in in vitro reactions but possessed a low immunogenecity. Immunoelectrophoretical analysis showed a mosaic character of antigen assembly in the preparations isolated from fungal cells and culture filtrates. In different antigens of C. immitis there have been revealed 4-7, in H. capsulatum 3-8 and in B. dermatitidis 3-6 components. The culture filtrates and "cell-saps" had a more complex antigenic spectrum: coccidioidin 7, histoplasmin 8, blastomycin 6; in C. albicans cell-sap, up to 20 antigens have been revealed. In the antigenic spectrum of C. immitis, H. capsulatum and B. dermatitidis common components prevailed, but in C. albicans no cross-reacting antigens have been revealed. Species- and phase-specific antigens have been found in preparations of H. capsulatum.
Insights
Protein-rich fungal antigens from Coccidioides immitis, Histoplasma capsulatum, Blastomyces dermatitidis, and Candida albicans induce potent immune responses. Polysaccharide-rich antigens show in vitro activity but low immunogenicity, highlighting the importance of antigen composition for diagnostic applications.
Area of Science:
- Medical Mycology
- Immunology
- Biochemistry
Background:
- Fungal infections caused by Coccidioides immitis, Histoplasma capsulatum, Blastomyces dermatitidis, and Candida albicans pose significant health challenges.
- Effective diagnosis and treatment rely on understanding fungal antigens and their immunogenic properties.
Purpose of the Study:
- To investigate methods for isolating fungal antigens with varying protein and polysaccharide content.
- To evaluate the immunogenicity and diagnostic potential of these isolated antigens.
Main Methods:
- Fungal cell disintegration using ultrasonication, freezing-thawing, and mechanical methods to obtain protein-rich antigens.
- Chemical treatments (beta-naphthol, ethanol, glycerine, alkali) to isolate polysaccharide-rich antigens.
- Immunoelectrophoresis to analyze the antigenic composition and complexity of preparations.
Main Results:
- Protein-rich antigens demonstrated higher activity in inducing cellular and humoral immune responses and were more specific for delayed-type hypersensitivity (DH) testing.
- Polysaccharide-rich antigens showed high activity in in vitro reactions but low immunogenicity.
- Immunoelectrophoresis revealed complex antigenic profiles, with common components among C. immitis, H. capsulatum, and B. dermatitidis, but not C. albicans. Species- and phase-specific antigens were identified in H. capsulatum.
Conclusions:
- The method of antigen isolation significantly impacts its protein/polysaccharide content and subsequent immunogenic and diagnostic utility.
- Protein-rich fungal antigens are superior for inducing immune responses and are valuable for diagnostic assays like DH testing.
- Understanding the antigenic complexity and cross-reactivity is crucial for developing specific diagnostic tools for fungal infections.