Human antibodies against a purified glucosylceramide from Cryptococcus neoformans inhibit cell budding and fungal growth

Human antibodies against a purified glucosylceramide from Cryptococcus neoformans inhibit cell budding and fungal growth

Author Rodrigues, Marcio L. Google Scholar
Travassos, Luiz R. Autor UNIFESP Google Scholar
Miranda, Kildare R. Google Scholar
Franzen, Anderson J. Google Scholar
Rozental, Sonia Google Scholar
Souza, Wanderley de Google Scholar
Alviano, Celuta S. Google Scholar
Barreto-Bergter, Eliana Google Scholar
Institution Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Abstract A major ceramide monohexoside (CMH) was purified from lipidic extracts of Cryptococcus neoformans. This molecule was analyzed by high-performance thin-layer chromatography (HPTLC), gas chromatography coupled,vith mass spectrometry, and fast atom bombardment-mass spectrometry. the cryptococcal CMH is a beta -glucosylceramide, with the carbohydrate residue attached to 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecanoic acid. Sera from patients with cryptococcosis and a few other mycoses reacted with the cryptococcal CMH. Specific antibodies were purified from patients' sera by immunoadsorption on the purified glycolipid followed by protein G affinity chromatography. the purified antibodies to CMH (mainly immunoglobulin G1) bound to different strains and serological types of C. neoformans, as shown by flow cytofluorimetry and immunofluorescence labeling. Transmission electron microscopy of yeasts labeled with immunogold-antibodies to CMH and immunostaining of isolated cell wall lipid extracts separated by HPTLC showed that the cryptococcal CMH predominantly localizes to the fungal cell wall. Confocal microscopy revealed that the beta -glucosylceramide accumulates mostly at the budding sites of dividing cells with a more disperse distribution at the cell surface of nondividing cells. the increased density of sphingolipid molecules seems to correlate with thickening of the cell wall, hence with its biosynthesis. the addition of human antibodies to CMH to cryptococcal cultures of both acapsular and encapsulated strains of C. neoformans inhibited cell budding and cell growth. This process was complement-independent and reversible upon removal of the antibodies. the present data suggest that the cryptococcal beta -glucosylceramide is a fungal antigen that plays a role on the cell wall synthesis and yeast budding and that antibodies raised against this component are inhibitory in vitro.
Language English
Date 2000-12-01
Published in Infection and Immunity. Washington: Amer Soc Microbiology, v. 68, n. 12, p. 7049-7060, 2000.
ISSN 0019-9567 (Sherpa/Romeo, impact factor)
Publisher Amer Soc Microbiology
Extent 7049-7060
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000167020000072

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