Thy1 Cell Surface Antigen (Thy1)

Thy-1 or CD90 (Cluster of Differentiation 90) is a 25–37 kDa heavily N-glycosylated, glycophosphatidylinositol (GPI) anchored conserved cell surface protein with a single V-like immunoglobulin domain, originally discovered as a thymocyte antigen. Thy-1 can be used as a marker for a variety of stem cells and for the axonal processes of mature neurons. Structural study of Thy-1 lead to the foundation of the Immunoglobulin superfamily, of which it is the smallest member, and led to the first biochemical description and characterization of a vertebrate GPI anchor.Thy-1 was discovered in early 1960s during the search for heterologous antisera against mouse leukemia cells. It was originally named theta (θ) antigen, then Thy-1 (THYmocyte differentiation antigen 1) due to its prior identification in thymocytes.