Sialic acid-binding Ig-like lectin 5 (SIGLEC5) is also known as CD33 antigen-like 2 (CD33L2), Obesity-binding protein 2 (OB-BP2), CD antigen CD170, which belongs to the immunoglobulin superfamily and SIGLEC (sialic acid binding Ig-like lectin) family. SIGLEC5 / CD170 is expressed by monocytic / myeloid lineage cells. SIGLEC-5 / CD33-L2 binds equally to alpha-2,3-linked and 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.