SSEA-4 specific antibody，clone MC-813，is reactive with Stage-Specific Embyronic Antigen-4，a carbohydrate antigen expressed on human teratocarcinoma cells （EC），embryonic stem cells （ES） and embryonic germ cells. It is also expressed on a subset of mesenchymal stem cells，erythrocytes，the erythroleukemic myeloid cell line K562，unfertilized oocytes and early cleaved stage oocytes.
