Galectins as immunoregulators during infectious processes: from microbial invasion to the resolution of the disease

Abstract

Recent evidence has implicated galectins, a family of evolutionarily conserved carbohydrate-binding proteins, as regulators of immune cell homeostasis and host-pathogen interactions. Galectins operate at different levels of innate and adaptive immune responses, by modulating cell survival and cell activation or by influencing the Th1/Th2 cytokine balance. Furthermore, galectins may contribute to host-pathogen recognition and may serve as receptors for specific interactions of pathogens with their insect vectors. Here we will explore the influence of galectins in immunological processes relevant to microbial infection and will summarize exciting recent work related to the specific interactions between galectins and their glycoconjugate ligands as critical determinants of pathogen recognition. Understanding the role of galectin-sugar interactions during the course of microbial infections might contribute to defining novel targets for disease prevention and immune intervention.

Functions of cell surface galectin-glycoprotein lattices

“…Galectins interact with β-galactoside-enriched glycoconjugates present in several pathogens [24][25][26]. While the nature of these interactions is not well-characterized, galectin oligomerization and/or lattice formation are likely to play a role.…”

Dendritic Cell Maturation Results in Pronounced Changes in Glycan Expression Affecting Recognition by Siglecs and Galectins

“…To date, 15 members have been characterized and although all galectins require ␤-galactosides for binding, several structural and functional differences have been described. In the immune system, galectins have been shown to operate at different levels in innate and adaptive immune responses by modulating cell survival and cell activation or by influencing the Th1/Th2 cytokine balance (24).…”

Galectin-1 Promotes Immunoglobulin Production during Plasma Cell Differentiation

“…Galectin-1 has also been proposed to shift the T cell polarization reaction from Th1 to Th2 by triggering apoptosis in Th1 cells (12,13). Galectin-1 also promotes surface exposure of phosphatidylserine (PS) 3 without accompanying apoptosis in human T cell lines (14). In addition to its role in regulating many aspects of T cell function, galectin-1 appears to have a role in stromal cells.…”

“…Galectins play important roles in regulating immune cell homeostasis, in host-pathogen interactions, and in tumorigenesis (1)(2)(3). Thus far, 15 mammalian galectins have been identified and sequenced (3,4).…”