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Updated: Aug 31, 2026
Passive Administration of Monoclonal Antibodies Against H. capsulatum and Others Fungal Pathogens
Published on: February 14, 2011
Preparation of a fluorescent antibody specific for the yeast phase of Histoplasma capsulatum
Abstract:
Kaufman, Leo (Communicable Disease Center, Atlanta, Ga.) and William Kaplan. Preparation of a fluorescent antibody specific for the yeast phase of Histoplasma capsulatum. J. Bacteriol. 82:729-735. 1961.-Rabbit anti-Histoplasma capsulatum globulin was conjugated with fluorescein isothiocyanate. This labeled antibody, in addition to staining six strains of H. capsulatum, exhibited strong cross-staining with ten strains of Blastomyces dermatitidis and numerous other species of fungi. Adsorption of the labeled antiglobulin either twice with cells of B. dermatitidis or twice with cells of Coccidioides immitis and once with cells of B. dermatitidis resulted in a good staining fluorescent antibody reagent, specific for yeast phase cells of H. capsulatum. Attempts to define the specific labeled antibody by the Ouchterlony procedure were unsuccessful. The specific conjugate did not give a complement fixation titer with yeast phase cells of B. dermatitidis or with coccidioidin. It did, however, show a 1:16 complement fixation titer with homologous yeast phase cells and a weaker reaction with histoplasmin.
Insights
Researchers developed a specific fluorescent antibody test for Histoplasma capsulatum yeast. This method improves diagnostic accuracy by reducing cross-reactivity with other fungi like Blastomyces dermatitidis.
Area of Science:
- Medical Mycology
- Immunology
- Microbiology
Background:
- Histoplasma capsulatum is a fungus causing histoplasmosis.
- Accurate identification of fungal pathogens is crucial for effective treatment.
- Existing diagnostic methods may lack specificity.
Purpose of the Study:
- To develop a specific fluorescent antibody reagent for the yeast phase of Histoplasma capsulatum.
- To improve the specificity of immunofluorescence assays for fungal identification.
Main Methods:
- Conjugation of rabbit anti-Histoplasma capsulatum globulin with fluorescein isothiocyanate.
- Testing the labeled antibody's reactivity against various fungal species, including H. capsulatum and Blastomyces dermatitidis.
- Adsorption of the labeled antibody with heterologous fungal cells to enhance specificity.
- Evaluation of specificity using Ouchterlony and complement fixation tests.
Main Results:
- The initial fluorescent antibody showed cross-reactivity with Blastomyces dermatitidis and other fungi.
- Adsorption with B. dermatitidis or Coccidioides immitis cells significantly improved specificity for H. capsulatum.
- The optimized reagent specifically stained yeast phase cells of H. capsulatum.
- Ouchterlony tests were unsuccessful in defining the specific antibody; complement fixation showed homologous reactivity.
Conclusions:
- A specific fluorescent antibody reagent for Histoplasma capsulatum yeast phase was successfully prepared through adsorption.
- This method enhances the specificity of immunofluorescence for diagnosing histoplasmosis.
- Further validation and application of this reagent in clinical diagnostics are warranted.
