Candida albicans serotype B strains synthesize a serotype-specific phospholipomannan overexpressing a beta-1,2-linked mannotriose.
Candida albicans strains consist of serotypes A and B depending on the presence of terminal beta-1,2-linked mannose residues in the acid-stable part of serotype A phosphopeptidomannan (PPM). The distribution of C. albicans serotypes varies according to country and human host genetic and infectious backgrounds. However, these epidemiological traits have not yet been related to a phenotypically stable molecule as cell surface expression of the serotype A epitope depends on the growth conditions. We have shown that C. albicans serotype A associates beta-mannose residues with another molecule, phospholipomannan (PLM), which is a member of the mannoseinositolphosphoceramide family. In this study, PLM from serotype B strains was analysed in order to provide structural bases for the differences in molecular mass and antigenicity observed between PLMs from both serotypes. Through these analyses, carbon 10 was shown to be the location of a second hydroxylation of fatty acids previously unknown in fungal sphingolipids. Minor differences observed in the ceramide moiety appeared to be strain-dependent. More constant features of PLM from serotype B strains were the incorporation of greater amounts of phytosphingosine C20, a twofold reduced glycosylation of PLM and overexpression of a beta-1,2 mannotriose, the epitope of protective antibodies. This specific beta-mannosylation was observed even when growth conditions altered serotype A PPM-specific epitopes, confirming the potential of PLM as a phenotypically stable molecule for serotyping. This study also suggests that the regulation of beta-mannosyltransferases, which define specific immunomodulatory adhesins whose activity depends on the mannosyl chain length, are part of the genetic background that differentiates serotypes.
Trinel
Pierre-André
PA
Inserm E0360, Physiopathologie des Candidoses, Faculté de Médecine, Pôle Recherche, 59037, Lille Cedex, France.
Delplace
Florence
F
Maes
Emmanuel
E
Zanetta
Jean-Pierre
JP
Mille
Céline
C
Coddeville
Bernadette
B
Jouault
Thierry
T
Strecker
Gérard
G
Poulain
Daniel
D
D000946:Antigens, Fungal / Q000737:chemistry / Q000276:immunology; D002176:Candida albicans / Q000737:chemistry* / Q000145:classification / Q000276:immunology* / Q000378:metabolism; D002518:Ceramides / Q000737:chemistry; D000939:Epitopes / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006017:Glycolipids / Q000737:chemistry* / Q000276:immunology*; D006031:Glycosylation; D006900:Hydroxylation; D008364:Mannosyltransferases / Q000378:metabolism; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D012703:Serotyping; D013107:Sphingolipids / Q000737:chemistry; D013110:Sphingosine / Q000031:analogs & derivatives / Q000032:analysis; D014312:Trisaccharides / Q000032:analysis* / Q000737:chemistry
D000946:Antigens, Fungal; D002518:Ceramides; D000939:Epitopes; D005227:Fatty Acids; D006017:Glycolipids; D013107:Sphingolipids; D014312:Trisaccharides; C400188:phospholipomannan; C023872:mannotriose; D008364:Mannosyltransferases; C012491:phytosphingosine; D013110:Sphingosine