Xylose-containing oligosaccharides (XOS)

Xylose-containing oligosaccharides are a functional class of carbohydrates characterized by the presence of xylose residues, most notably found in plant-derived xylo-oligosaccharides (XOS) and as part of the core structure of various glycoproteins and proteoglycans. In human health, these molecules primarily function as prebiotics, where they are selectively fermented by beneficial gut bacteria such as Bifidobacterium, leading to the production of short-chain fatty acids that support intestinal barrier function and immune homeostasis (Aachary & Prapulla, 2011). Furthermore, specific xylose-containing N-glycans serve as the initial linkage unit for glycosaminoglycans on proteoglycans, playing a vital role in the structural integrity of the extracellular matrix (Prydz & Dalen, 2000). In the field of immunology, these structures are recognized as cross-reactive carbohydrate determinants (CCDs) that can elicit IgE responses, frequently causing diagnostic challenges by producing false-positive results in allergy tests (Altmann, 2016). While they are being investigated for their role in managing metabolic and inflammatory conditions via microbiome modulation, they are categorized as a chemical class rather than a discrete therapeutic target protein. Consequently, their pharmacological relevance lies in their use as dietary supplements or their role as interfering epitopes in diagnostics rather than as sites for traditional small-molecule drug binding (Bax et al., 2015).

Other names

Xylo-oligosaccharidesXylo-glycansCross-reactive carbohydrate determinantsCCDXylansXyloglucan oligosaccharides

Xylose-containing oligosaccharides primarily act as prebiotics that undergo fermentation by anaerobic bacteria in the colon, such as Bifidobacterium, to produce short-chain fatty acids (Aachary & Prapulla, 2011). In an immunological context, they function as epitopes (CCDs) for IgE antibodies, leading to cross-reactivity in allergic sensitization (Altmann, 2016).