Recombinant Mouse MGL1/CD301a Protein, CF

Mouse MGL1 (macrophage galactose N-acetyl-galactosamine (GalNAc) specific Lectin 1, CD301a), also called ASGP-BP (asialoglycoprotein binding protein), is a 38 kDa type II transmembrane glycoprotein of the C-type lectin family (1). Two MGL proteins are encoded by separate genes in the mouse, but share 91% amino acid (aa) identity in the extracellular domain (ECD) (2). Only one MGL occurs in human and rat, and this is more structurally similar to mouse MGL1 than MGL2. However, mouse MGL1 binds Lewis X, in contrast to human MGL and mouse MGL2 which both bind specifically to terminal GalNAc residues (2). Lewis X is a trisaccharide commonly found on leukocytes and some tumor cells. Both mouse MGL proteins are expressed on immature dendritic cells. Mouse MGL1 and MGL2 are markers for connective tissue macrophages of a type termed alternately activated macrophages. These macrophages are induced by IL-4 that is produced during Th2-mediated inflammatory responses to parasitic infections or allergic airway inflammation (3, 4). Quantitative RT-PCR after helminth infection shows a peak of MGL1 expression at 7 days, while MGL2 shows increasing expression for at least 29 days (3). This, and data from MGL1 knockout mice (5), indicates that MGL1 is critical during the formation of granulation tissue, with MGL2 remaining involved during chronic infection. Mouse MGL1 is synthesized with an N-terminal 35 aa cytoplasmic region, a 21 aa transmembrane segment and a 248 aa ECD. The ECD contains one 129 aa carbohydrate recognition domain (CRD) that shows 78% and 63% aa identity with rat and human MGL, respectively.