The influence of surface carbohydrates during in vitro infection of mammalian cells by the dermatophyte Trichophyton rubrum

• Published in: Research in microbiology 2004-04, Vol.155 (3), p.144-153
• Main Authors: Esquenazi, Daniele, Alviano, Celuta S., de Souza, Wanderley, Rozental, Sonia
• Format: Article
• Language: English
• Subjects: Adhesin; Animals; Biological and medical sciences; Carbohydrates - physiology; Cell Adhesion - physiology; Cellular interaction; CHO Cells; Cricetinae; Cytoskeleton - metabolism; Cytoskeleton - physiology; Dermatophytes; Endocytosis - physiology; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Glycoprotein; Glycoproteins - physiology; Human mycoses; Humans; Infectious diseases; Macrophages, Peritoneal - cytology; Macrophages, Peritoneal - parasitology; Medical sciences; Mice; Microbiology; Microscopy, Electron, Scanning; Miscellaneous; Mycology; Mycoses; Mycoses of the skin; Periodic Acid - metabolism; Tinea - microbiology; Tinea - pathology; Trichophyton - physiology; Trichophyton - ultrastructure; Trichophyton rubrum
• ISSN: 0923-2508; 1769-7123
• DOI: 10.1016/j.resmic.2003.12.002

In order to better understand the role played by surface glycoconjugates during host cell adhesion and endocytosis of Trichophyton rubrum, we looked for the presence of carbohydrate-binding adhesins on the microconidia surface and their role on cellular interaction with epithelial and macrophages cells. The interaction of T. rubrum with chinese hamster ovary epithelial cells and their glycosylation-deficient mutants demonstrated a higher adhesion index in Lec1 and Lec2 mutants, that express mannose and galactose, respectively. Endocytosed fungi were shown preferentially in Lec2 cells. Addition of the carbohydrates to the interaction medium, pretreatment with lectins and with sodium periodate decreased the adhesion and endocytic index for all mutants. The ability of the fungus to penetrate into mammalian cells was confirmed in experiments using macrophages treated with cytochalasin D. Flow cytometric analysis showed that this fungus recognizes mannose and galactose. The binding was inhibited by the addition of methyl α- d-mannopyranoside and methyl α- d-galactopyranoside, and showed higher fluorescence intensity at 37 than at 28 °C. Trypsin treatment and heating of the cells reduced the binding, suggesting a (glyco) protein nature for the microconidia adhesins. The presence of lectin-like molecules in fungus cell could be observed by scanning electron microscopy of the fungus incubated with colloidal-gold labeled neoglycoproteins. Our results suggest that T. rubrum has the ability to invade mammalian cells and expresses carbohydrate-specific adhesins on microconidia surface that recognize mannose and galactose. These adhesins may play an important role on the adhesion and invasion of the fungus during the infectious process of dermatophytosis.