Scavenger receptor that displays several functions associated with host defense. Promotes binding and phagocytosis of Gram-positive, Gram-negative bacteria and yeast. Binds also to sialyl Lewis X or a trisaccharide and asialo-orosomucoid (ASOR). Mediates the recognition, internalization and degradation of oxidatively modified low density lipoprotein (oxLDL) by vascular endothelial cells (By similarity). Binds to several carbohydrates including Gal-type ligands, D-galactose, L- and D-fucose, GalNAc, T and Tn antigens in a calcium-dependent manner and internalizes specifically GalNAc in nurse-like cells (By similarity). The extracellular domain forms a stable trimer (By similarity). The extracellular domain interacts with fibrillar amyloid-beta peptide. Forms clusters on the cell surface. Expressed in vascular endothelial cells in the heart, in perivascular macrophage and smooth muscle cells. Expressed in plaques-surrounding reactive astrocytes located in cerebral cortex and hippocampus and in leptomeningeal vessels showing characteristics of cerebral amyloid angiopathy (CAA) in a double transgenic mouse model of Alzheimer disease (at protein level). Strongly expressed in lung. Moderately expressed in heart, skeletal muscle, spleen, liver, brain, colon, testis, stomach and kidney. Expressed in neonatal astrocytes. Expressed in reactive astrocytes and vascular/perivascular cells in the brain of a double transgenic mouse model of Alzheimer disease. Expressed in embryo at 9 dpc, increases progressively to a peak at 14 dpc and gradually decreases until 19 dpc. Up-regulated in activated microglia and by fibrillar amyloid-beta peptide in activated astrocytes.