Glycoprotein Structure and Function in Mammalian Immune Systems: Molecular Architecture and Regulatory Networks

Glycoproteins represent fundamental architectural and regulatory components of mammalian immune systems, orchestrating complex molecular interactions through their carbohydrate modifications. This comprehensive review examines the structural diversity, biosynthetic pathways, and functional roles of glycoproteins in both innate and adaptive immunity. The glycan code, mediated by cell surface glycoproteins and their cognate lectins, governs critical processes including pathogen recognition, immune cell trafficking, and intercellular communication. In adaptive immunity, antibody glycosylation serves as a molecular switch modulating effector functions, whilst the complement system relies extensively on glycoprotein components for its cascading activation. Evolutionary analysis reveals the co-evolution of glycosylation machinery with immune complexity, driven by host-pathogen interactions and regulatory network innovations. Environmental and metabolic factors dynamically influence glycoprotein expression, with aberrant glycosylation patterns serving as hallmarks of autoimmune diseases and malignancy. Advanced analytical methodologies, including mass spectrometry and functional immune assays, continue to elucidate the complexity of the mammalian glycoproteome. This review synthesises current understanding of glycoprotein-mediated immune regulation and highlights emerging therapeutic opportunities targeting these critical molecular mediators.