Multivalency

13Multivalent Lectin–Glycan Interactions in the Immune System

João T. Monteiro and Bernd Lepenies

Immunology Unit & Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany

13.1 Introduction

Accomplishing a more profound understanding of the structural and functional role of protein–glycan interactions in immunity is fundamental to gain insights into the pathogenesis of diseases such as allergies, cancer and autoimmune diseases [1,2]. Carbohydrates constitute the most abundant class of biomolecules on Earth and represent one of the most commonly added modifications to proteins, thereby fine‐tuning protein functions [3,4]. It is estimated that more than half of the proteins in humans are glycosylated [5]. The role of glycans in nature is widespread, ranging from energy storage, to molecular recognition for intracellular trafficking, and host–pathogen interactions [6]. The biosynthesis of polysaccharides and glycoconjugates is not encoded directly in the genome, but is a result of the differential expression of glycoenzymes. Glycosyltransferases and glycosidases catalyze glycosylation reactions and the hydrolysis of glycosidic bonds, respectively, often leading to heterogeneous mixtures of glycoforms that possess distinct physiological activities [7]. Typically, glycans are covalently bound to proteins or lipids. Since the individual interactions between proteins and carbohydrates are usually ...