Immunomodulatory effects of human placenta gangliosides.

The immunomodulatory properties of the major gangliosides of human placenta were studied. All the gangliosides investigated suppressed the cytotoxic activity of human natural killer cells. The magnitude of the inhibitory effect depended on ganglioside structure. Gangliosides GM1, GM3, and GD3 were the most effective suppressors. Some of the placental gangliosides (GD3, GD1a, IV3NeuAc-nLc4Cer, VI3NeuAc-nLc6Cer) also inhibited lymphoblastic transformation, and one of them (GM3) strongly stimulated the Con-A-induced T-suppressor activity of human lymphocytes. It is suggested that the combined action of the placental gangliosides on maternal effector cells may be involved in the defence of the human embryo against the maternal immune system.