Anti-human embryonic stem cell monoclonal antibody Hesca-2 binds to a glycan epitope commonly found on carcinomas

Hesca-2, a monoclonal antibody (mAb) IgM raised to the human embryonic stem cell (hESC) line BG-01v, binds with high affinity (nM) to the disaccharide epitope (Galβ1-3GlcNAc) on a glycan microarray. This epitope was expressed on pluripotent progenitor hESCs in culture, but not in various differentiated cells derived from hESC based on immunofluorescence microscopy. Hesca-2 stains a limited subset of cells in adult human tissues (eg, esophagus and breast). This mAb also crossreacts in immunofluorescence microscopy studies with several human ovarian cancer cell lines and is cytotoxic to them based on the release of cytosolic enzyme lactate dehydrogenase into the media. Hesca-2 immunohistochemically stained tissue from a number of human tumors, including ovary, breast, colon, and esophageal cancer. These data suggest that Hesca-2 recognizes a surface marker found both in stem cells and certain cancer cells.