PREPARATION OF A FLUORESCENT ANTIBODY SPECIFIC FOR THE YEAST PHASE OFHISTOPLASMA CAPSULATUM

Abstract

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 stain-ing 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.