Carbohydrate antigens are polysaccharides and glycoconjugates of multiple structural configurations. Although recognition of carbohydrates as antigens starts from microbial polysaccharides, the range of investigation of carbohydrate antigens has been substantially extended. The era of glycomics just begun, and Creative Biolabs as a professional research institute has gained considerable fame in the world and our seasoned scientists already devote to this emerging field for more glycans and carbohydrate antigens details. Besides, there are a series of glycoengineering technologies and custom antibody services can be provided that contain a pre-consultation, technical support, and data interpretation.
Carbohydrate antigens are polymeric chains of diverse monomeric sugar molecules, including glucose (Glc), galactose (Gal), mannose (Man), fucose (Fuc), rhamnose (Rha), N-acetylglucosamine (GlcNAc), N-acetylmannosamine (ManNAc), N-acetylfucosamine (FucNAc), N-acetylgalactosamine (GalNAc), N-acetylneuraminic acid (NeuAc), and N-glycolylneuraminic acid (NeuGc). The antigenic determinants of the above polymers depend on the property of sugar units and the type of glycosidic linkage between them. The positions of the carbons in the glycosidic linkage are usually indicated in the polymer’s structural designation, for instance, Glca1,2Gal or NeuAca2,6Gal. This linkage is introduced during elongation of the chain by a gene-specific glycosyltransferase. Polymeric sugars (polysaccharides) may exist in an unbound state or be linked to peptides, proteins or lipids.
Fig.1 Common glycoconjugates on human cells. (Chua, 2017)
Carbohydrate antigens present in many structural configurations, such as polysaccharides, proteoglycans, glycoproteins, glycolipids, glycosaminoglycans, and glycosphingolipids. Based on origins, carbohydrate antigens are traditionally divided into microbial antigens and alloantigens. Microbes express the former while the latter is produced by mammalian cells.
Carbohydrates may be complete-antigens, like microbial polysaccharides, in that they can induce reactive antibodies in certain species. They’re also likely to be components or antigenic determinants of glycoconjugates and such carbohydrate moieties (or oligosaccharides) are called after haptens in immunology. They determine the specificity of immune response but cannot evoke an immune reaction in their free, unconjugated forms. Consideration of glycoconjugates as carbohydrate antigens makes it necessary to further classify carbohydrate antigens into two large categories, the T-dependent (TD) and T-independent (TI) forms.
Table.1 Classification of carbohydrate antigens. (Wang, 2006)
Carbohydrates are excellent in generating structural diversity and are prominent in the surface display. They comprise valuable biological information and can be characteristically recognized by either soluble or membrane-bound cellular proteins.
In the higher eukaryotic organisms, expression of cellular glycoconjugates, particularly complex carbohydrate structures, is frequently cell type-specific or tissue-specific. In microbes, many sugar chains, including those on the surface of a microbial cell and those secreted outside it, have been regarded as ‘‘signatures of specific pathogens”. Exploring the biological content of sugar chains is the current focus of postgenomic research.
In addition, the expression of some tumor-associated carbohydrate antigens (TACAs) could define the rate, stage, and phenotype of cancer development and reveal prognostic value in the clinics. Several of these are now considered as adhesion molecules that affect the site of metastasis. Monoclonal antibodies to TACAs may not only serve as classic immunological reagents but as anti-adhesion agents for the prevention of tumor progression.
Antibodies mediate the primary mechanism for active elimination of infectious pathogens from the bloodstream. Carbohydrate antigens have capabilities to induce carbohydrate-specific antibodies and react with them. And this induction could occur without the help of T lymphocytes and also be recognized by cell-surface lectins.
Carbohydrate antigen, as a classical immunological topic, has obtained a renewed interest in the new millennium. Aided by versatile GlycoOpitimize™ platforms, Creative Biolabs offers antibody glycoengineering services and antibody identifications targeting carbohydrate antigens for global clients, and our research includes but not limited to:
No matter what anti-carbohydrate antibody applications needed, Creative Biolabs can utilize easy-to-access techniques to identify carbohydrate antigens and acquire anti-carbohydrate antibodies in a high-quality manner. If there is no related option you're looking for, please contact us for more information.
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