The monoclonal antibody H3F3D1 reacts with galectin-2. Galectins are β-galactoside-binding lectins. They have a characteristic carbohydrate recognition domain (CRD) and are widely expressed in a wide range of organisms. Galectins are involved in the regulation of cell proliferation, inflammation, cell adhesion and cell death. Based on structural features, mammalian galectins have been classified as proto, chimera or tandem repeats. Galectin-2 is of the proto type. Proto types contain one CRD per subunit and are usually homodimers of non-covalently linked subunits. Although galectins lack a typical secretion signal peptide, they are present not only in the cytosol and the nucleus, but also in the extracellular space. During the infection process, galectins have diverse effects on cells involved in innate immune responses, including macrophages, dendritic cells, neutrophils and mast cells. For example many host-microorganism interactions have been shown to involve protein-carbohydrate recognition. Thereby facilitating the interaction with colonizing microorganism, or initiate innate and adaptive immune responses against the pathogen.Galectin-2 is structurally related to galectins-1 (43% sequence identity to gal-1), but is primarily expressed in the gastrointestinal tract and induces apoptosisin activated T-cells. Human and mouse gal-2 share ca 65% amino acid sequence similarity. The exact function of gal-2 remains unclear until now. Interaction studies showed binding of gal-2, present in macrophages and smooth muscle cells, to lymphotoxin-α and also α-and β-tubulins, implicating involvement in regulation of cytokine secretion relevant for the pathogenesis of myocardial infarction. Furthermore, Gal-2 has proven growth-regulatory activity, is reactive with apoptotic cells, and has the potential to modulate cell adhesion.