Roles of Glycans and Glycopeptides in Immune System and Immune-Related Diseases

Abstract

Almost all of the key molecules in organisms involved in the innate and adaptive immune response (including immunoglobulins, cytokines and cytokine receptors, complements, CD molecules, adhesions, T-cell receptors and major histocompatibility complex molecules) are glycoproteins. Besides, foreign antigens, such as many viral envelope proteins, are glycoproteins too. Carbohydrates attached to proteins or peptides are classified by the nature of their linkages to the protein, mostly as either N-linked (N-acetylglucosamine to asparagines) or O-linked (N-acetylgalactosamine to serine or threonine) oligosaccharides. The glycans have three major roles: firstly, the sugars confer stability on the proteins to which they are attached, protecting them from proteases and non-specific protein-protein interactions. Secondly, glycans play key roles in signal transduction, control of cell development and differentiation. Thirdly, specific regions of the oligosaccharide chains provide recognition epitopes, which influence innate and adaptive immune responses. Glycopeptides not only provide specific oligosaccharides, but also have specific information of amino acids sequences. The glycans and glycopeptides not only influence the structure and functions of immune molecules, but also influence the immune response. In addition, changes in glycans or glycopeptides may have a significant role in a variety of human immune-related diseases, such as rheumatoid, autoimmune disease, Wiskott-Aldrich syndrome, infection disease, cancer, etc. In this article, the roles of N-, O-glycans and glycopeptides in immune system and immune-related diseases are discussed. The potential therapeutic significance of the information is also mentioned.

Knockdown of Mgat5 Inhibits Breast Cancer Cell Growth with Activation of CD4+ T Cells and Macrophages

“…Carbohydrate chains in the mature N-glycans include the typical high-mannose, hybrid, and complex forms. N-acetylglucosaminyltransferase V (Mgat5), also known as GnT-V, plays an important regulatory role in the synthesis of complex N-glycans and this process is highly conserved between yeast and mammals (4).…”

Structural Characterization of Neutral Oligosaccharides by Laser-Enhanced In-Source Decay of MALDI-FTICR MS

“…However, fragment ions below m/z 700 were not observed. Therefore, the CID of this compound did not provide the complete sequence and branched point information even after MS 3 . By contrast, the LEISD spectrum of DFpLNH II (Figure 4) shows more structural information and a better S/ N. For this instrument with three-stage CID at most, the CID method is not applicable for analysis of labile oligosaccharides.…”

“…arbohydrates play important roles in multiple biological processes such as anticoagulants, immunomodulators, antigenic microbial recognition factors, inflammatory response addressins, fertilization, and cell adhesion molecule, as forms of either glycolipids or glycoproteins [1][2][3]. Because of the continuing discoveries of new roles for oligosaccharides whose structures are in many cases related to their biological functions, it is important to elucidate their structures.…”

Parameter Sweep Workflows for Modelling Carbohydrate Recognition

“…Carbohydrate recognition is a phenomenon critical to a number of biological functions in humans including highly specific responses of the immune system to pathogens [18][19][20], and the interaction and communication between cells [21]. Unlike polypeptides and proteins, oligosaccharides do not form well-organised tertiary structures in solution and they lack secondary structure motifs.…”