Nanomolar concentrations of gangliosides stimulate primary humoral response.

Exogenous gangliosides act as immunosuppressors when applied at micromolar concentrations corresponding to their average level in human plasma. Here we show that at nanomolar concentrations the gangliosides GD3, GD1a and GM1 can act as immunostimulators markedly enhancing the number of plaque-forming cells in mouse splenocyte culture responding to sheep erythrocytes. At such low concentration these gangliosides as well as GM3 were not able to influence significantly proliferative responses of splenic B and T lymphocytes or of cytotoxic T-cells.