Putative adhesion molecule that mediates sialic-acid dependent binding to cells. Preferentially binds to alpha-2,3- or alpha-2,6-linked sialic acid. The sialic acid recognition site may be masked by cis interactions with sialic acids on the same cell surface. Expressed by peripheral blood leukocytes (neutrophils and monocytes but not eosinophils). Found in liver, fetal liver, bone marrow, placenta, spleen and in lower levels in skeletal muscle, fetal brain, stomach, lung, thymus, prostate, brain, mammary, adrenal gland, colon, trachea, cerebellum, testis, small intestine and spinal cordon. Contains 1 copy of a cytoplasmic motif that is referred to as the immunoreceptor tyrosine-based inhibitor motif (ITIM). This motif is involved in modulation of cellular responses. The phosphorylated ITIM motif can bind the SH2 domain of several SH2-containing phosphatases. Belongs to the immunoglobulin superfamily. SIGLEC (sialic acid binding Ig-like lectin) family. Siglec-9