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Comparative stability, sensitivity and specificity studies with different lots of Blastomyces dermatitidis yeast and
M L Orr1, J L Bono, R O Abuodeh
1Department of Biological Sciences, Idaho State University, Pocatello 83209.
Abstract:
Comparative studies were performed to assess the stability and lot-to-lot variation of Blastomyces dermatitidis yeast and mycelial phase lysate antigens. Four lots were prepared from each growth phase of B. dermatitidis strain T-58 (canine isolate) during a 14-month period. Serum specimens from dogs with blastomycosis, histoplasmosis, coccidioidomycosis, cryptococcosis and aspergillosis were assayed for antibody content using an alkaline phosphatase enzyme-linked immunosorbent assay (ELISA). The four lots of the yeast phase reagents were similar with respect to sensitivity and specificity, and the absorbance readings were approximately four times greater with sera from dogs with blastomycosis than with histoplasmosis or coccidioidomycosis. Even less cross-reactivity was evidenced when the sera from dogs with cryptococcosis and aspergillosis were assayed. In contrast, the four lots of the mycelial lysate reagents were considerably less reactive and more cross-reactive than the yeast phase antigens and, as above, the four reagents retained their activity after prolonged storage. Therefore the results indicated that the lysate antigens exhibited a great deal of stability and lot-to-lot variations in activity were not observed.
Insights
This study found that Blastomyces dermatitidis yeast phase antigens are stable and show minimal lot-to-lot variation. These antigens demonstrate high sensitivity and specificity for diagnosing blastomycosis in dogs.
Area of Science:
- Veterinary Mycology
- Immunodiagnostics
Background:
- Blastomycosis is a significant fungal disease in dogs, necessitating reliable diagnostic tools.
- Antigen stability and lot-to-lot consistency are crucial for the accuracy of diagnostic assays.
Purpose of the Study:
- To evaluate the stability and lot-to-lot variation of Blastomyces dermatitidis yeast and mycelial phase lysate antigens.
- To assess the diagnostic performance of these antigens in canine sera.
Main Methods:
- Preparation of four lots of B. dermatitidis yeast and mycelial phase antigens over 14 months.
- Assay of canine serum specimens from various fungal infections using an alkaline phosphatase enzyme-linked immunosorbent assay (ELISA).
Main Results:
- Yeast phase antigens exhibited consistent sensitivity and specificity across all lots.
- Yeast phase antigens showed significantly higher reactivity with blastomycosis sera compared to other fungal infections.
- Mycelial phase antigens were less reactive and showed more cross-reactivity than yeast phase antigens.
- All tested antigen lots maintained activity after prolonged storage.
Conclusions:
- Blastomyces dermatitidis yeast phase lysate antigens are stable and exhibit minimal lot-to-lot variation.
- Yeast phase antigens are promising for the development of sensitive and specific diagnostic tests for canine blastomycosis.