Effect of disialoganglioside GD3 on the subgel, gel and fluid phases of cationic DODAB vesicles.

GD3 is a disialoganglioside overexpressed in several types of cancer cells. The synthetic cationic lipid DODAB has been successfully employed as a vaccine adjuvant, and would be suitable to enhance GD3 immunogenicity. Here, mixed dispersions of GD3 and DODAB were characterized by Differential Scanning Calorimetry (DSC) and Electron Paramagnetic Resonance (EPR) spectroscopy. GD3 is miscible with DODAB, and decreases the DODAB gel-fluid transition cooperativity. GD3 does not affect the temperature hysteresis between gel-fluid and fluid-gel transitions. GD3 does not affect the formation of a subgel phase in DODAB bilayers cooled below 15 °C. GD3 decreases the acyl chain packing of the DODAB subgel phase, which could explain the broad and shallow exothermic event between 5 °C and 20 °C that appears on thermograms of mixed dispersions. These results might contribute to the development of novel GD3-based cancer immunotherapies, including at the low temperatures involved in cold chain stability.