Capsular Localization of theCryptococcus neoformansPolysaccharide Component Galactoxylomannan
Year: 2008
Type: article
Abstract: Cryptococcus neoformans capsular polysaccharide is composed of at least two components, glucuronoxylomannan (GXM) and galactoxylomannans (GalXM). Although GXM has been extensively studied, little is known about the location of GalXM in the C. neoformans capsule, in part because there are no serological reagents specific to this antigen. To circumvent the poor immunogenicity of GalXM, this antigen was conjugated to protective antigen from Bacillus anthracis as a protein carrier. The resulting conjugate elicited antibodies that reacted with GalXM in mice and yielded an immune serum that proved useful for studying GalXM in the polysaccharide capsule. In acapsular cells, immune serum localized GalXM to the cell wall. In capsulated cells, immune serum localized GalXM to discrete pockets near the capsule edge. GalXM was abundant on the nascent capsules of budding daughter cells. The constituent sugars of GalXM were found in vesicle fractions consistent with vesicular transport for this polysaccharide. In addition, we generated a single-chain fraction variable fragment antibody with specificity to oxidized carbohydrates that also produced punctate immunofluorescence on encapsulated cells that partially colocalized with GalXM. The results are interpreted to mean that GalXM is a transient component of the polysaccharide capsule of mature cells during the process of secretion. Hence, the function of GalXM appears to be more consistent with that of an exopolysaccharide than a structural component of the cryptococcal capsule.
Source: Eukaryotic Cell
DOI: 10.1128/ec.00331-08
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
Funders: National Science Foundation, Howard Hughes Medical Institute, U.S. Department of Energy, Yeshiva University, University of Georgia, Agence Nationale de la Recherche, National Institutes of Health, Albert Einstein College of Medicine, Yeshiva University, National Heart, Lung, and Blood Institute, National Cancer Institute, National Institute of Allergy and Infectious Diseases, National Center for Research Resources
Awards: G177305599, G2436179761, 600 MHz NMR Spectrometer, G2525293057, G2531885203, Synergy of Host Defense Mechanisms in the Lung, G2773611754, Immunology and Immunooncology Training Program, G4480737473, G4617214234, G4622003401, 600 MHz NMR Spectrometer, G624453842, G6259444000, Protective antibodies for Cryptococcal Infections, Acquisition of a Structural NMR Resource, Northeast Biodefense Center, G8744572376, G9000096188, G9000324242, Molecular Characterization of C. neoformans Antibodies
OpenAlex ID: W2148094479