Location by immunoelectron microscopy of carcinoembryonic antigen on cultured adenocarcinoma cells.

The tissue-culture cell line HT-29, derived from a primary colon adenocarcinoma and previously shown to secrete carcinoembryonic antigen (CEA), was examined by immunoelectron microscopy for the location of CEA in relation to the cells. CEA was closely adjacent to the plasma membrane, a location indistinguishable from that of alloantigens and other tumor-associated antigens.