Cell surface markers in human embryonic stem cells.

The pluripotent nature of human embryonic stem cells (hESCs) is based on their potential to form every cell type in the body. Prior to use in directed differentiation strategies, these cells need to be thoroughly characterized. The large number of glycoproteins and carbohydrates that exist on the cell surface provide an excellent opportunity for characterizing hESCs and a means to delineate pluripotent and differentiated cell types. A panel of 14 lectins, based on their specificity for a variety of carbohydrates and carbohydrate linkages, along with stage-specific embryonic antigen-4 (SSEA-4), have been chosen to examine hESCs for other potential pluripotent markers. These studies have been achieved by binding quantitation by flow cytometry and binding localization in adherent colonies by immunocytochemistry. We have shown that certain lectins may be used as markers that are associated with the pluripotent state of hESCs because binding percentages and binding localization of these lectins are similar to those of SSEA-4. This presents options for systematic classification of pluripotent hESCs and for distinguishing differentiated hESC types based on glycan presentation that accompanies differentiation.