Sialoadhesin (SN)

Sialoadhesin is a cell adhesion molecule found on the surface of certain cells of the immune system called macrophages. It is defined as an I-type lectin, since it contains 17 immunoglobulin (Ig) domains (one variable domain and 16 constant domains), and thus also belongs to the immunoglobulin superfamily (IgSF). Since sialoadhesin binds sialic acids with its N-terminal IgV-domain, it is also a member of the SIGLEC family. Alternate names for sialoadhesin include siglec-1 and CD169 (cluster of differentiation 169).

Sialoadhesin predominately binds neutrophils, but can also bind monocytes, natural killer cells, B cells and a subset of cytotoxic T cells by interacting with sialic acid molecules in the ligands on their surfaces.