Specific antibody response to oligomannosidic epitopes in Crohn's disease

Abstract

Elevated antibody levels against the yeast Saccharomyces cerevisiae have been reported in sera from patients with Crohn's disease and not with ulcerative colitis. The aim of the study was to identify the nature of the epitopes supporting this antibody response. Whole cells from different S. cerevisiae strains were selected in immunofluorescence assay for their ability to differentiate the antibody responses of patients with Crohn's disease and ulcerative colitis. Their cell wall phosphopeptidomannans were then tested as antigen in enzymelinked immunosorbent assay (ELISA) against sera from 42 patients with Crohn's disease, 20 patients with ulcerative colitis, and 34 healthy controls. Graded chemical degradations were performed on the most reactive strain phosphopeptidomannan. The discriminating epitope was determined through gas-liquid chromatography-mass spectrometry. The greatest discrimination among patients with Crohn's disease, ulcerative colitis, and controls was obtained with Su1, a S. cerevisiae strain used in brewing of beer. ELISA directed against phosphopeptidomannan of this strain was 64% sensitive and 77% specific for discriminating Crohn's disease versus ulcerative colitis and 71% sensitive and 89% specific for Crohn's disease versus controls. Periodate oxidation and selective degradation demonstrated that the most important polysaccharide epitope was shared by both the acid-stable and the alkali-labile domains of the phosphopeptidomannan. The determination of oligomannose sequences of S. cerevisiae Su1 phosphopeptidomannans suggested that a mannotetraose, Man(133)Man(132)Man(132)Man, supported the serological response seen in Crohn's disease. Further identification of the immunogen eliciting this antibody response as a marker of the disease may help to understand its etiology.

Antibodies to flagellin indicate reactivity to bacterial antigens in IBS patients

“…12 Anti-Saccharomyces cerevisiae antibodies, occurring mainly in CD patients, recognize distinct carbohydrate epitopes of yeast cell wall mannan. 13,14 The ANCA are predominantly found in UC and present as atypical perinuclear ANCA (p-ANCA). 15 Antibodies to exocrine pancreas (PAB) are highly specific for CrohnÕs disease (CD), however, the sensitivity is only moderate.…”

Anti-Saccharomyces Cerevisiae Antibodies (ASCA), Phenotypes of IBD, and Intestinal Permeability: A Study in IBD Families

“…Anti-Saccharomyces cerevisiae antibodies directed against cell wall oligomannosidic epitopes is a serological marker for CD (19)(20). They have a sensitivity of 60% and a specificity of 80-95% for differentiating CD from controls (21)(22)(23).…”

Anti‐Saccharomyces cerevisiae mannan antibodies in inflammatory bowel disease: comparison of different assays and correlation with clinical features

“…Since the initial description by Main et al, 1 antibodies against the S. cerevisiae (ASCA), a yeast commonly used in the food industry, have been found in CD, with a prevalence ranging from 35 to 65%. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This figure, however, derives from studies on different populations, where different assays have been employed. Saccharomyces cerevisiae has not been directly implicated in the pathogenesis of CD.…”

“…The ASCA detection was performed in France as previously described. 3,4 Briefly, antigens consisted of phosphopeptidomannan (PPM) extracted from yeast cells of S. cerevisiae Su1 strain from cultures growth in bioreactors. Plates were coated with 100 lL of PPM at a concentration of 1 lg/mL in sodium carbonate buffer (60 mm, pH 9.6) for 1 h at 37°C and overnight at 4°C, in moist chambers, and then washed four times in TNT (50 mm Tris-HCL, 150 mm NaCl, 0.05% Tween-20, pH 7.5).…”

“…The association between serum antibody reactivity to the cell wall mannan polysaccharide of the yeast Saccharomyces cerevisiae (Anti-S. cerevisiae mannan antibodies, ASCA) and Crohn's disease (CD), but not ulcerative colitis (UC), has been described over a decade ago and confirmed by several investigators. [1][2][3][4] Their exact origin and, more importantly, the epitope against which they are directed, are unknown. The increased prevalence in unaffected relatives of inflammatory bowel disease (IBD) patients, 5,6 and a significant familial aggregation for unaffected relatives, 7 has suggested that ASCA may represent a new specific marker of genetic susceptibility for CD.…”