Aspergillus galactomannan enzyme-linked immunosorbent assay cross-reactivity caused by invasive Geotrichum capitatum.

We report three cases of invasive Geotrichum capitatum infection in patients with acute leukemia for which an enzyme-linked immunosorbent assay (ELISA) for Aspergillus galactomannan was positive, with no evidence of aspergillosis. Supernatants obtained from suspensions of 17 G. capitatum strains gave positive reactions with the Aspergillus galactomannan ELISA. These clinical and laboratory data seem to suggest that G. capitatum produces a soluble antigen that is cross-reactive with Aspergillus galactomannan.

Duodenal colonization by Geotrichum candidum in a child with transient low serum levels of IgA and IgM.

Fungal colonization was observed in the duodenal biopsy specimens of a nine-year-old girl who complained of anorexia and epigastric pain. Endoscopy revealed gastric redness and Geotrichum candidum was identified in the duodenum by histopathology and tissue culture. Immunologic work-up showed low serum levels of IgA and IgM. She was treated with ranitidine and antacids for gastritis. At follow-up, the levels of immunoglobulins had normalized, no fungal elements were detected, and clinical symptoms had disappeared. Duodenal invasion by G. candidum has not been described so far. Duodenal colonization by G. candidum may occur when mucosal immunity is disturbed and may be the source of dissemination in severe immunodeficiency states.

Some biochemical characteristics of the early phase of immunomodulation.

The study estimates some biochemical changes of chosen immunological and biochemical parameters after intraperitoneal application of a) immunomodulators of microbial origin--Propionibacterium acnes and Geotrichum candidum, b) chemical substances--indomethacin and phenobarbital. The estimation was concentrated above all to the changes of chemiluminiscence, phagocytic activities, the amount of cAMP in peritoneal macrophages, the amount of liver cytochrome P-450 and cAMP in the liver, spleen and thymus. The experiments also included histological examination of the spleen, thymus, lungs and diaphragm. The effect of Propionibacterium acnes was evident as soon as 24 hrs after application. In the frame of studied parameters, there was manifested the nonspecific activation of the immune system by the mechanisms independent to oxygen. The early changes were accompanied by the increase of cAMP in macrophages. In contrary, the intraperitoneal application of Geotrichum candidum activated the release of oxygen radicals from peritoneal macrophages. The amount of the cytochrome P-450 correlated to the intensity of immunomodulation. On the other hand, the induction of cytochrome P-450 by phenobarbital decreased the value of several immunity indices.

Partial purification and characterization of mold antigens commonly found in foods.

Rapid methods are needed for detection of molds in foods; therefore, an enzyme-linked immunosorbent assay was developed. The extracellular and mycelial antigens for Mucor, Aspergillus, Cladosporium, and Geotrichum species were partially purified and characterized. The molecular masses of the mycelial and extracellular antigens, as determined by size exclusion chromatography, ranged from 4.5 x 10(5) to 6.7 x 10(5) Da. There was only one main antigenic peak separated by Sepharose CL-4B and concanavalin A-Sepharose columns for Mucor, Cladosporium, and Geotrichum mycelial and extracellular antigens, but there were two for Aspergillus mycelial antigens and three for Aspergillus extracellular antigens. These antigens contained 10 to 50% protein which was part of the active site since protease digestion significantly decreased antigenic activity. Neutral sugars, ranging from 13 to 75%, made up the rest of the active site, and < 1% phosphate was detected in mycelial antigens. Geotrichum, Cladosporium, and Aspergillus antigens contained mainly glucose, galactose, and mannose. Mucor antigens contained these sugars plus fucose. The percentage of sugars differed between the mycelia and extracellular antigens. Enzymatic digestion and competitive inhibition tests using different sugar derivatives showed that galactosyl residues with beta linkages were immunodominant for Aspergillus, Geotrichum, and Cladosporium antigens and mannosyl residues with alpha linkages were immunodominant for Mucor antigens.

Enzyme-linked immunosorbent assay for detection of molds in cheese and yogurt.

An enzyme-linked immunosorbent assay was developed for the detection of molds in dairy products. New Zealand White female rabbits were immunized with .45 mg of partially purified extracellular antigen from freeze-dried culture filtrates of Aspergillus versicolor, Cladosporium herbarum, Geotrichum candidum, Mucor circinelloides, and Penicillium chrysogenum. Blood was drawn at various intervals, and antibodies were separated and purified. Antibody-peroxidase conjugates were prepared with the following ratios being the optimum ones: A. versicolor 10:20; C. herbarum 5:10; G. candidum 1:10; M. circinelloides 5:5; and P. chrysogenum 10:10. The assays were sensitive within a range of 1 ng to 1 microgram/ml, depending on the mold used. Inhibition tests were done for each mold with concentrations of 0 to 5000 micrograms/ml of antigen. The enzyme-linked immunosorbent assay tests for Cladosporium, Geotrichum, and Mucor were only inhibited by antigens from other species of the same genus; whereas there was crossreaction between antibodies and antigens of species of Penicillium and of Aspergillus. Citrate buffer was best for extracting the mold from cheese and yogurt. The extract was adjusted to pH 7.2 and ELISA was performed. Results showed that these molds can be detected in Cheddar and cottage cheeses and yogurt within 2 d, which is before mold growth is visible in these products.

Carbon assimilation and extracellular antigens of some yeast-like fungi.

Many yeast-like fungi assimilated n-hexadecane, butylamine and putrescine as sole carbon sources. Methanol was not assimilated. This points to a physiological similarity to endomycetous, hydrocarbon-utilizing yeasts. Stephanoascus ciferrii assimilated uric acid, adenine and allantoin as sole source of carbon and nitrogen. All strains of Geotrichum candidum and many other yeast-like fungi assimilated acetoin and butan-2,3-diol. Assimilation tests for adenine, uric acid, allantoin, acetoin and butan-2,3-diol were found to be suitable for taxonomic purposes. Extracellular antigens immunologically related to those produced by Geotrichum candidum were detected in the cell-free culture liquids of several yeast-like fungi. The extracellular antigen excreted by Stephanoascus ciferrii was species-specific.