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Serodiagnostic value of culture filtrate antigens from aspergilli with septate phialides
Abstract:
Culture filtrate antigens from 6 typical isolates of Aspergillus fumigatus, 6 isolates with septate phialides, and isolates of A. fumigatus var. ellipticus, A. fishceri, A. flavus and A. niger were studied in tests with 2,100 samples of serum originating from 1,452 patients suffering from miscellaneous diseases, including 60 cases of aspergillosis, 850 samples of serum from apparently healthy blood donors and 522 sera referred to us as positive for C-reactive protein. The culture filtrate antigen prepared from a septate-phialide-strain proved to be most useful in detecting precipitating antibodies in the sera of patients suffering from aspergillosis caused by A. fumigatus. The antigen from this strain not only gave sharper and a larger number of precipitin bands than others but also proved to be an invaluable tool in the serodiagnosis of 5 to 56 (8.9%) A. fumigatus cases in which all other antigens repeatedly failed to give a positive result. The serological data also suggest that the septate-phialide strains are mutants of A. fumigatus and should not be classified as a separate species.
Insights
A novel Aspergillus fumigatus antigen from a septate-phialide strain significantly improved serodiagnosis of aspergillosis. This antigen detected antibodies in cases missed by other methods, suggesting these strains are mutants.
Area of Science:
- Medical Mycology
- Immunology
- Diagnostic Microbiology
Background:
- Accurate serodiagnosis of invasive aspergillosis remains challenging.
- Traditional Aspergillus fumigatus antigens have limitations in sensitivity.
- Identifying novel antigens is crucial for improving diagnostic capabilities.
Purpose of the Study:
- To evaluate the diagnostic utility of culture filtrate antigens from various Aspergillus species and strains.
- To identify the most effective antigen for detecting precipitating antibodies in aspergillosis patients.
- To investigate the taxonomic relationship between septate-phialide strains and Aspergillus fumigatus.
Main Methods:
- Preparation of culture filtrate antigens from multiple Aspergillus isolates, including typical A. fumigatus, septate-phialide strains, and other species.
- Serological testing using immunodiffusion assays with 2,100 patient sera, including confirmed aspergillosis cases, healthy donors, and C-reactive protein positive samples.
- Comparative analysis of precipitin band formation and diagnostic yield across different antigens.
Main Results:
- The antigen from a septate-phialide strain demonstrated superior performance, yielding sharper and more numerous precipitin bands.
- This antigen successfully diagnosed 8.9% of A. fumigatus cases where other antigens failed.
- Serological data indicated that septate-phialide strains are likely mutants of A. fumigatus, not a distinct species.
Conclusions:
- Culture filtrate antigen from a septate-phialide strain is highly effective for the serodiagnosis of Aspergillus fumigatus infections.
- This improved antigen enhances diagnostic sensitivity, particularly in challenging cases.
- Septate-phialide strains should be considered variants of A. fumigatus based on serological evidence.