Occurrence of serotypes among Histoplasma capsulatum strains.

Kaufman, Leo (Communicable Disease Center, Atlanta, Ga.), and Sharon Blumer. Occurrence of serotypes among Histoplasma capsulatum strains. J. Bacteriol. 91:1434-1439. 1966.-Extensive studies with a fluorescent antibody specific for the yeast form of Histoplasma capsulatum indicated that, although most strains of H. capsulatum stained intensely, others stained weakly and some did not stain. These observations suggested that antigenic variants of the fungus existed. To test this hypothesis, reciprocal cross-staining and adsorption procedures were performed with fluorescein-labeled antiglobulins to four strains of H. capsulatum. Fifty-six strains of H. capsulatum and 11 strains of H. duboisii were studied. The data indicate that at least five serotypes of H. capsulatum occur. One is closely related antigenically to H. duboisii and Blastomyces dermatitidis.