title: Characterization of Scedosporium apiospermum glucosylceramides and their involvement in fungal development and macrophage functions.
abstract: Scedosporium apiospermum is an emerging fungal pathogen that causes both localized and disseminated infections in immunocompromised patients. Glucosylceramides (CMH, GlcCer) are the main neutral glycosphingolipids expressed in fungal cells. In this study, glucosylceramides (GlcCer) were extracted and purified in several chromatographic steps. Using high-performance thin layer chromatography (HPTLC) and electrospray ionization mass spectrometry (ESI-MS), N-2'-hydroxyhexadecanoyl-1-β-D-glucopyranosyl-9-methyl-4,8-sphingadienine was identified as the main GlcCer in S. apiospermum. A monoclonal antibody (Mab) against this molecule was used for indirect immunofluorescence experiments, which revealed that this CMH is present on the surface of the mycelial and conidial forms of S. apiospermum. Treatment of S. apiospermum conidia with the Mab significantly reduced fungal growth. In addition, the Mab also enhanced the phagocytosis and killing of S. apiospermum by murine cells. In vitro assays were performed to evaluate the CMHs for their cytotoxic activities against the mammalian cell lines L.929 and RAW, and an inhibitory effect on cell proliferation was observed. Synergistic in vitro interactions were observed between the Mab against GlcCer and both amphotericin B (AmB) and itraconazole. Because Scedosporium species develop drug resistance, the number of available antifungal drugs is limited; our data indicate that combining immunotherapy with the available drugs might be a viable treatment option. These results suggest that in S. apiospermum, GlcCer are most likely cell wall components that are targeted by antifungal antibodies, which directly inhibit fungal development and enhance macrophage function; furthermore, these results suggest the combined use of monoclonal antibodies against GlcCer and antifungal drugs for antifungal immunotherapy.
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Rollin-Pinheiro
authors.affiliation: Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Livia Cristina
authors.initials: LC
authors.lastname: Liporagi-Lopes
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Jardel Vieira
authors.initials: JV
authors.lastname: de Meirelles
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
authors.forename: Lauro M de
authors.initials: LM
authors.lastname: Souza
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Eliana
authors.initials: E
authors.lastname: Barreto-Bergter
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002460:Cell Line; D017077:Culture Media, Conditioned / Q000378:metabolism; D005963:Glucosylceramides / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D017964:Itraconazole / Q000494:pharmacology; D008264:Macrophages / Q000382:microbiology*; D008297:Male; D051379:Mice; D021681:Scedosporium / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism* / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D017077:Culture Media, Conditioned; D005963:Glucosylceramides; D017964:Itraconazole; D000666:Amphotericin B