This invention describes how to obtain nano-particulate adjuvants formed by different synthetic variants of the GM3 ganglioside. Depending on the fine structure of the fatty acid in the ceramide of the synthetic GM3, it is possible to obtain adjuvants for the specific and specialised stimulation of the humoral or cellular immune response against accompanying antigens. In particular, the invention provides immunogenic vaccine compositions that comprise peptides, polypeptides or proteins and the aforementioned nanoparticles, which are formed through the dispersion of hydrophobic proteins of the outer membrane complex (OMC) of Neisseria meningitidis with fully synthetic variants of the GM3 ganglioside.
