SIGLEC5 contains 2 Ig-like C2-type (immunoglobulin-like) domains and 1 Ig-like V-type (immunoglobulin-like) domain. It belongs to the immunoglobulin superfamily and SIGLEC (sialic acid binding Ig-like lectin) family. SIGLEC5 is expressed by monocytic/myeloid lineage cells. It is found at high levels in peripheral blood leukocytes, spleen, bone marrow and at lower levels in lymph node, lung, appendix, placenta, pancreas and thymus. It is also expressed by monocytes and neutrophils but absent from leukemic cell lines representing early stages of myelomonocytic differentiation. SIGLEC5 is a putative adhesion molecule that mediates sialic-acid dependent binding to cells. It 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.
