Siglec-7 is a 75 kD type I transmembrane protein and a member of the family of sialic acid-binding immunoglobulin-like lectins (Siglecs), also known as p75/AIRM1. It is primarily found on NK cells and monocytes. The cytoplasmic domain of Siglec-7 contains immunoreceptor tyrosine-based inhibitory motif (ITIM). CD328 mediates sialic acid-dependent cell-cell binding and functions as an inhibitory receptor of NK cells. CD328 preferentially binds to sialylated glycans with alpha2,8 disialyl and alpha2,6 sialyl residues.