Immunology of histoplasmosis: Humoral and cellular activity from a polysacchari-de-protein complex and its deproteinized fraction in experimentally immunized mice

Abstract

In a previous publication it was reported that a polysaccharide-protein complex (PPC), sensitive to beta-glucosidase, was isolated from Histoplasma capsulatum. This complex was strongly reactive in an agar gel diffusion assay with sera from patients with histoplasmosis, but was unreactive with sera from patients with coccidioidomycosis. Here, the studies with human sera have been expanded and attempts were made to determine the response of mice immunized with nonviable H. capsulatum or Coccidioides immitis to PPC or its deproteinized fraction (D-PPC) using more sensitive tests for antibody and including also test for cell-mediated immunity. Histoplasmin and coccidioidin were compared with PPC or its deproteinized fraction (D-PPC) in all assays. In a counterimmunoelectrophoresis (CIE) assay, PPC and D-PPC reacted only with sera from patients with histoplasmosis, whereas cross reactions were noted with histoplasmin and coccidioidin using heterologous sera. Cross-reaction were observed with all four antigen preparatins and both types of antisera using a microcomplement fixation assay. The assay for macrophage migration inhibitory factor (MIF) was also relatively nonspecific, in that inhibition occurred with cells from animals sensitized with Histoplasma or Coccidioides using both homologous and heterologous antigens. In the footpad assay, histoplasmin and coccidioidin were highly cross-reactive in animals sensitized with the heterologous fungus, but the PPC and D-PPC from H. capsulatum elicited significant reactions only in animals sensitized with Histoplasma.

The interaction between Histoplasma capsulatum cell wall carbohydrates and host components: relevance in the immunomodulatory role of histoplasmosis

“…Galactomannan-protein complexes from the mycelial phase cell wall of H. capsulatum have antigenic properties; they can induce delayed-type hypersensitivity in guinea pigs and inhibit macrophage migration factor release , Reiss et al 1974. A deproteinized polysaccharide-protein complex isolated from H. capsulatum, which immunolocalized mainly to the mycelial phase cell wall by colloidal gold labelling (Taylor & Bojalil 1977, Taylor et al 1980, Pereira-Morales et al 1998, shares common characteristics with the galactomannan-protein complex reported by Reiss et al (1974). Fungal galactomannan complexes may be involved in a mechanism to protect the organism against its own serinethiol protease, an enzyme associated with pathogen dissemination through the extracellular matrix, as described in paracoccidioidomycosis (Matsuo et al 2006).…”

Identification of the infectious source of an unusual outbreak of histoplasmosis, in a hotel in Acapulco, state of Guerrero, Mexico

“…A deproteinized polysaccharide‐protein complex of Histoplasma (DPPC‐Histo), as described elsewhere [14], was used as antigen for dot‐ELISA. The purified DPPC‐Histo (50 ng 20 μl −1 of protein) was applied in separate wells to a 0.45 μm nitrocellulose membrane narrow strip (BioTrace, GelmanSciences, Inc. MI, USA) using a 96‐well microfiltration Bio‐Dot apparatus (Bio‐Rad, Richmond, CA, USA).…”

Retrospective serological study of histoplasmosis in Mexico

“…Crude antigens, histoplasmin, paracoccidioidin, coccidioidin, aspergillin, and candidin, were prepared from culture filtrates [ 1 1 -131, previously standardized in the laboratory for different test conditions [12,14,151.…”