Galectins as Danger Signals in Host–Pathogen and Host–Tumor Interactions: New Members of the Growing Group of “Alarmins”?

Abstract

Nearly 30 years passed since several glycobiology laboratories independently found that various cell extracts contained soluble b-galactoside-binding proteins (1–19). As all mammalian lectins are either released through the classical secretory pathway or synthesized as membrane proteins, it was expected that these soluble b-galactosidebinding lectins also followed this biosynthetic pathway for their externalization to the extracellular space, where the majority of b-galactoside-containing glycoconjugates are found. Independently, immunologists also identified a protein synthesized by immune cells, following activation with inflammatory stimuli, that was first called Mac-2 or IgE-binding protein and has since then been renamed “galectin-3” (20, 21).