Cell wall composition and serological reactivity of Histoplasma capsulatum serotypes and related species.

The composition of the cell walls of strains of Histoplasma capsulatum that were reactive in the complement-fixation test and that reacted with fluorescein-tagged specific anti-H. capsulatum serum were compared with the cell walls of H. capsulatum and Histoplasma duboisii that did not react in these serological tests. The cell walls of the serologically reactive strains of H. capsulatum were much more susceptible to the action of proteinases and to chitinase than were the serologically nonreactive strains, but were less susceptible to hydrolysis by 3% NaOH or 2 n H(2)SO(4). The walls of the serologically reactive strains had higher chitin, amino acid, and hexosamine contents, but they were lower in a "lactic acid" component that was released by alkaline hydrolysis of the nonreactive strains. The cell walls of strains of H. duboisii were similar to the walls of the serologically nonreactive strains of H. capsulatum. Chemical analyses of the cell walls of the various strains clearly support the serological typing of H. capsulatum and H. duboisii strains reported by Kaufman and Blumer.