Interaction between ganglioside-containing liposome and rat T-lymphocyte: confocal fluorescence microscopic study

Interaction between rat T-lymphocytes and a ganglioside (GM3, GD3, GT1b, or GQ1b)-containing liposome was investigated in vitro. The direct stimulation of T cell by a ganglioside-containing liposome was followed by monitoring an increase in the intracellular calcium signal using a confocal laser fluorescence microscopic method. The GT1b- or GQ1b-containing liposome strongly stimulated the cell, while the GM3- or GD3-containing liposome showed much less effect. Free gangliosides did not stimulate the cell at all under the same condition. The extent of the stimulation depended on the surface density of GT1b on the liposome accompanied by a clear threshold concentration. The efficiency of this direct T cell stimulation with the ganglioside-containing liposome was closely related to the efficiency of the tumor growth suppression reported previously by ourselves.