Ganglioside GM2 on the K562 cell line is recognized as a target structure by human natural killer cells

Although human NK cells lyse a wide spectrum of target cells, the precise target structure recognized by NK cells has not yet been elucidated. In order to define a possible relationship between gangliosides on human target cells and susceptibility to NK lysis, 14 human leukemia and lymphoma cell lines were studied. A significant correlation was observed between the quantity of ganglioside GM2 on the target cells and sensitivity to NK lysis. In a single-cell binding assay purified GM2 specifically inhibited human NK cell binding to K562 target cells while other gangliosides did not inhibit binding. The competitive inhibition of NK cells by GM2 was restricted to the source of tissue from which GM2 was isolated. These results indicate that GM2 is a strong candidate as a target recognition structure for human NK cells.