TRA-1-81 Antigen

**Semantic type:** Immunologic Factor|Organic Chemical

**Definition:** A neuraminidase-resistant carbohydrate epitope on the keratan sulfated glycoprotein podocalyxin. This epitope is expressed on the surface of human embryonic stem cells and its expression is turned off once these cells differentiate during development. Reactivation of expression is found on the surface of embryonal carcinoma cells.

**Synonyms:** - TRA-1-81 - TRA181 - tra1-81